How Long Does Weed Stay in Your System? [Precise Calculator]

Today you are going to learn exactly how long THC (including edibles) stays in your system and how to speed up the detox process.

The main psychoactive compound in cannabis—THC—can stay in the body for days and weeks.

The detection window depends on the testing method: Most common are blood, urine, sweat, saliva and hair testing.

However, have in mind that:

  • Most of the tests in use today detect THC in levels above 50 ng/dL, so until you get below that level you will keep testing positive.
  • Body fat percentage plays a huge role in how quickly you are able to flush THC out—the more body fat you have, the longer the THC will stay in your system as that’s where it’s stored.
  • Only THC is detectable in tests while other cannabinoids (such as CBD) are not.

How long does weed stay in your system (Chart)

How long does weed stay in your system (Chart)

Depending on the testing method, here is how long THC stays in your system:

  • Blood — 1 to 7 days
  • Urine — 7 to 30 days
  • Saliva — 1 to 7 days

Precise THC detox calculator

While the chart does provide a decent basic overview, it’s not exactly precise.

We’ve made an accurate THC drug test calculator which takes into account two things that influence metabolism of THC the most: Body fat percentage and urine THC metabolite levels.

Body fat (%):

Urine metabolite level (ng/mL):

Time to clear THC (days):

As you can see, to use this calculator you’ll need to know your urine metabolite levels. Metabolite levels of frequent users hover at around 200-250 ng/mL, measured one day after using cannabis.

The only way to get exact numbers is by using a home kit THC test—don’t go for the most basic one as you’ll need a “multi-level” test that shows THC levels in ng/mL. Here is a cheap multi-level test I found on Amazon.

If you don’t know what your body fat percentage is, take a look at this visual comparison for a rough estimate.

Chart to assess body fat levels visually

As I’ve said, there are several popular cannabis testing methods and passing them depends on the testing method and the frequency of cannabis use.

Here’s a quick overview.

Weed stays in urine from 7-70 days

Urine testing does not look for THC, but a non-psychoactive metabolic intermediate—THC-COOH.

After using cannabis, our liver metabolizes THC into THC-COOH which is then stored in urine.

Again, for how long THC stays in urine depends mostly on the frequency of use.

If you’ve used marijuana just once, weed will stay in your urine for about 7 days.

If you’ve smoked 2 to 4 times recently but didn’t use it since, weed will stay in your urine for 10 to 18 days.

If you use cannabis 5 or 6 times a week, it will stay in your urine for 30 to 48 days.

Medical marijuana users and daily recreational users need a bit more time to completely detox—about 50 to even 70 days.

Weed stays in blood from 1 to 7 days

THC is only detectable in blood for a short amount of time, hence this testing method is not that popular anymore.

After smoking, THC runs through the blood and gets stored into fat, where it stays for longer periods of time.

In general, if you’re not a regular smoker and you only took a few puffs, weed will stay in your blood for 1-2 days.

If you’ve used cannabis a few times in the past week, THC will stay in your blood for about 3 days afterward.

Yet, if you are a regular, everyday user you’ll need around 7 days to flush THC out completely.

Weed stays in hair for up to 90 days

With this testing method, THC can be detected from just a single hair sample taken 1.5 inches from the scalp.

This makes the hair test really scary and accurate—it can detect even picograms of THC.

Note: If your first hair sample tests positive for weed, they might ask you to provide a second sample.

Weed stays in saliva for 1-7 days

Saliva marijuana tests are usually used by the police, through devices like the Dräger 3000.

Weed can be detected in saliva just an hour after consuming cannabis.

If you only used marijuana once, it can stay in your saliva for up to 24 hours.

If you are an occasional user, weed can stay in your saliva for up to 72 hours.

If you are a regular heavy user (or a daily medical user), weed can stay in your saliva for up to a week.

Roadside saliva tests have been very controversial recently. The problem is that you can test positive to THC without even being high, so it’s still very difficult to determine if the driver is actually impaired or not.

Weed stays in sweat for 7-28 days

Sweat tests are not that common and they are usually used for monitoring patients during drug rehab treatments and employment programs.

THC metabolites can be detected in sweat for about one to four weeks.

This depends on two factors: How much sweat you produce and how much you smoke.

Also take into account environmental factors, such as temperature and air humidity.

Here’s how this test works:

THC sweat patches are applied to the skin and are usually worn from 7 to 14 days. After that period, patches are taken off for testing.

The amount of produced sweat is subjective, and so the accuracy of this testing method is somewhat limited—and it’s hard to control if someone wore the patch all the time, of course.

How long do edibles stay in your system?

Consumption method is very important when it comes to cannabis testing.

For example, when you eat a cannabis brownie, it takes much longer to get “high” when compared to smoking.

When you eat an edible, cannabis has to go through the entire digestion process before cannabinoids enter the bloodstream.

That’s why edibles stay in your system for 7 to 30 days.

Just 5 days after eating an edible, 80 to 90% of THC gets flushed out but the remaining 10% can be detected for up to 4 weeks.

How to speed up the THC detox process?

The best way to flush THC out of your system and pass the test is pretty simple—total abstinence for a set period of time.

If you know you’re going to get tested for cannabis, I suggest you reverse engineer the chart above and stay cannabis-free for that time period.

If it’s already too late and you don’t have the time, there are a few things you can do to speed up the detox process.

These tips could help, but there are no guarantees they will work.

Take note that research showed that people with a fast metabolism, lower body fat percentage, and lower BMI can flush THC out faster than people with standard BMI.

But, here is what you can do.

1) Drink plenty of water

Staying hydrated is essential for your health in general. So if you want to flush marijuana out your system, start drinking a lot of water a few days before the test.

Keep in mind that drinking a lot of water can make your urine clear so this could look suspicious as well.

2) Eat the right foods

As THC is stored in fat, you’ll need to avoid fatty and greasy foods as well as things rich in sugar and sodium. That means no junk food and red meat.

You’ll need a lot of food rich in fiber and antioxidants so stick to fruits, vegetables, and whole grains to detox faster.

Also, vitamin C should be your new best friend. Lemonades and citrus juices are full of electrolytes which are great detoxing agents. Tea will also help you flush THC out, so drink a few cups of green, black or white tea a couple of days before your test.

Vitamin B3 is great when you’re looking to cleanse your system from just about anything. Avocados and potatoes are one of the biggest natural sources of vitamin B3 (also known as niacin).

3) Exercise and sweat

Cardio is the best way to burn fat, which is also where THC metabolites live. By exercising, we sweat more, excrete fluids and we eventually speed up the THC detox.

A workout that mixes cardio and strength would be the best to flush marijuana out, starting a few weeks prior to testing.

But, there is one tricky thing when it comes to exercising. Don’t do it on the day of testing. In fact, try to avoid all exercise a couple of days before the big day.

Even though exercise burns fat, that process also releases more THC metabolites into your blood, which could be a bad choice for the testing day.

If you’re really worried about the test, a sauna can also do wonders.

4) Get a lot of sleep

It’s now common knowledge that cannabis relieves stress and induces sleep. However, if you have to take a drug test you’ll have to get some rest without weed.

When we sleep, our whole body recovers for the following day. It’s our own, natural detox mechanism.

So, a few days (or weeks) before taking the test, try to get as much sleep as possible. Give yourself a few nights off and try to go to bed earlier than usual.

92 thoughts on “How Long Does Weed Stay in Your System? [Precise Calculator]”

  1. I am 56 yrs. old. I thank the younger generation for keeping Cannabis alive. My passion is deep and my story is long about cannabis use. Thank God for this wonderful herb.

    • Hi Adrianna,

      Thank you for your lovely comment. Hope you found this article useful. We would like to hear more about your long experience with cannabis.



  2. Ciao helena,se possibile volevo sapere che tipo di analisI a cosa servono e se possibile che ésca fuori qualche traccia di sostanza stupefacente.GRAZIE
    Prelievo ematico per: EMOCROMO,GOT,GPT,YGT,SIDEREMIA,CTD

  3. Hi good story glad I found it. One slight correction on the length of time THC Cannabis can remain in the system specific to saliva tests. Here in Australia and many other countries they use a Drager Saliva testing machine and it has a 99% accuracy. However there is a challenge between detection and impairment. BMI is a standard element of the Drager as you mention thanks folks miss that, and thus detection time can be WEEKS not 7 days per Drager. We have had many court cases on it here also. Here in Australia the law is not based on impairment only “the presence of an illicit substance” in this case THC. Just part of the mess that is Cannabis law reform herre in Australia.

  4. I’m with Loren above.
    Re the roadside testing; I believe you can refuse it, it’s not like a breath alcohol test which is mandatory, and enforcable.
    Some would say our whole system of justice and law is illegitimate, seeing as how they are now profit driven corporations that must trick you into contracting with them…
    Can’t say I’ve ever tried it, I try and keep beneath the radar.
    A good many years ago in a country far far away I was involved with a friendly fraternity of motorcycle enthusiasts.
    Their mantra was ‘do not talk to police, do not incriminate yourself’…
    But what I’m doing, I’m going to see my friendly doctor, and inform Her I have ‘discovered’ medical marijuana, hence why it’s been so long I haven’t come back for opioid pain killers. I’m not waiting for the govt’s permission for them to grow, manage and denature a vegetable. Thank you I am quite capable and self sufficient, if the need arises.
    So, unlike their denatured product branded, licensed ‘safe’ product, my source is as God gave.
    So, if ever I do get entrapped in a roadside test, I can refer to my doctor, that I do indeed have a condition where I am self medicating with MM, albiet black market.
    Which will make it a lot easier than getting a note from my doc after the imaginary event.
    I’m 56 and I’m not really on the cops radar, but best to pre-empt the situation.
    I have genuine medical needs which have been diagnosed, but I rejected all their treatment plans in favour of old reliable, my first love, we’ve been together now 35 years!

  5. I weigh 115 have a high matabolism, and very skinny with barley any fat. If I smoked weed once and have a drug test in 9 days will I pass? Please need a answer soon I’m nervous

  6. I am 6’3” and 270 lbs, i smoked extracts 97% THC and smoked marijuanna everyday for 3 months. I have been clean for 60 days, bit i am still teating dirty, will i be clean by 70 days or will my usage push me to a longer rimeline to be clean of THC?

    • Andy, there’s no telling exactly especially because you’ve been smoking concentrates and since we don’t have a baseline. Most tests test positive on anything above 50 ng/dL, so until you get below that level you will keep testing positive. Body fat percentage plays an important role in how quickly you clear THC. To calculate exactly how long it’ll take you to flush THC out, I would skip over to the bottom of this post and follow the 3 step tutorial:

  7. I have a question that I haven’t seen answered in the hundreds of forums I’ve been perusing so far:

    I started smoking about 5 years ago (daily smoking for the past 4). I stopped shaving my legs 7 or 8 years ago. Since my leg hair was at maximum length, would it still test positive for THC?

    From what I understand THC is deposited through the root into *growing* hair. So I’m wondering if I have max length body hair from before I started smoking would it test clean?

    (If you have an account on another MJ forum site, please ask for me lol, thanks!)

  8. High! I haven’t shaved my legs in years. The last time was probably 3 years before I started smoking cannabis daily. I tried it once about 3 or 4 months after I shaved for the last time, and then didn’t smoke again for years. Since my leg hair was at maximum length before I started smoking would it still be possible for the hair to have THC(COOH)? Any info is useful, and if you have an account on any other MJ forums can you please ask there too? haha Thanks!

  9. Hi I smoked weed for about 5 months and I weigh 130 and have a terribly high metabolism for a 19 year old guy can someone tell me when it will be out of my system

    • Yes, depending on your metabolism and how often you use edibles (or smoke weed in general), it can show up on a saliva testa up to a week after consumption.

  10. Hi, i have been a frequent user, for a year or so. I lost my drivers licence for it. I ussually smoked about 3 g, a week. I stopped about 10 ago completly. I was wondering how long should i wait to get tested, to pass the urine test? I am pretty thin about 65 kg at 180cm.

  11. Hi, I occasionally used THC e-cigarette(almost never) and tried 2 hits last night and felt nothing. But I had a bite of MJ chocolate around half month ago and I am going to have a test after a week. Can I pass that test? I am 182cm and 80kg, 23 years old.

  12. Hi I had one 10 mg cookie and kinda puked after I got high. Have test in a week. What should I do. Little body fat,work out 6 times a week.age 24

  13. My last edible was a gummy 46 days ago. I haven’t smoked or consumed any weed since then.I have a pre employment urine drug test in 3 days.. before I stopped I would eat 5mg gummies once every other night to help me sleep. I passed 2 different brands of drug test. My only concern is that the home test test at 50ml.. Do u think I’m good even if they test for lower amounts

  14. I have been clean sense dec 8th it’s now feb 4th and last night I had half of a gummy edible it’s way under 20mg let’s say 10 mg and I took a home test today and I failed how long will test dirty for I’m 5’2 125lb female

  15. I have a question, the last time I had one puff of weed in early december and haven’t had any more, would any of it still be in my system?

  16. I had 1 chocolate candy filled with carmel edible of christmas day. I have a urine test on valentines day. Im female…5’8 190lbs…will i test dirty. That was my only time eating 1.

  17. I take a couple puffs of my vape nightly for the last few months. Compared to smoking joints, how long should I expect that to be out of my system? Please and thanks?

  18. Hi, I haven’t smoked in 5 years. I took 4-5 puffs on 01/27. Will it still be in my system? Planning on taking at home test today. I am 30, weigh 173, 5’6’m and BMI is around 30%. Thanks.

  19. hi i took five hits off a blunt on feb 23 this yr. im only about 125 and it was my first time how long would it take to leave my system?

  20. Hey guys,

    I’ve been smoking everyday, multiple times a day for about two years now. I had my last puff at the end of January and have been clean since. I’ve also been on the keto diet and working out. Lost around 20lbs at this point. I have a drug test within the next week or so. What are the odds I pass? Any information would be greatly appreciated!

  21. Don’t smoke at all went on vacation and had 1 edible of 5 mg. Haven’t had anything since! How long would it take for me to pass a hair follicle test?

  22. HI!

    So I have a cartridge that was rated at 96% THC which I stopped smoking about 8 days ago. I’m 6′ 5″ and weigh 193 pounds. This coming week I have a couple interviews both of which will drug test me if I take the position. Do you think I will pass? To know how much I smoked, I would maybe hit it once or twice a week if that. Each hit would only be for 3 seconds max as well. I’m guessing that once I take my first drug test I will be about 12-16 days clean. Also I only drink water, tea, and homemade lime juice. I also started to run last week, and am currently on a diet of not having any junk food at all.


  23. I’ve been smoking everyday for years till the past 2 weeks which has been just here and there. I have a job interview within the next week and they do a mouth swab. Do you think I’m safe?? Please help

  24. Hi, I ate a 50 mg cake. this is my first time. I had a panic attack and 2 days after I still feel it in my head. how long will the feeling stay? and how long does it take to be out of my system? I’m 25, 60 kg, 170 cm high.
    Thanks in advance for your help.

  25. Hey, so I’ve been indulging in edibles (cookies, gummies, rice crispy treats) since January of this year. I take them fairly regularly now (50-350 mg, mainly cookies) & I’ve been high off my ass since April 10th. A couple of days ago, I got hired. Idk if where I’m gonna be working at does drug testing (honestly forgot) but I asked my friend since he works for the same company & he told me to stay clean for 2 months. So it could be a random test… I had a small piece of cookie that same day (less than a quarter), I’m 21, 5″1, & weigh 123 lbs. How long will it remain in my system? please help

  26. You know, I’m with you all on the knowledge of the testing. It sux that we all have to go through this. I’m over 50 and have been smoking since I was 19. We all have done the fast and famine routine to “test clean”. I even hate the terminology. Why? I try to have the same level of conversation with my doctor as I do about my blood pressure pills. It is a medicine for many. Avoiding opiates is key these days. It terrible that we, Americans, many Veterans have to balance opiate use, risk of addiction to opiates, uneven metabolism of opiates and so many accidental ODs. Crazy to pass out opiates like this, people dropping dead, and then all the testing for weed. I have a NORML shirt from 1992. It still isn’t normal. What is wrong with our culture that prisons are for profit? And a non-lethal plant is what has put many many many people in those prisons. Disrupting families in so many ways and causing a whole ripple of “criminality” for weed.
    Maybe a collective of folks that have legal access to edibles could do an informal study of how the “testing” is with various types of edibles. I do not like them. It is difficult to titrate the dose to perfect and a more definite timeframe to “sober enough to drive” on weed. I could put together a survey type of thing folks could print out – their physical characteristics re % body fat and other info, exactly what edible (form – gummy, chocolate, candy) and dose, brand, as much info about the specific edible. Graph that with not only “testing”, but weigh ourselves before testing – I am assuming that a lot of people have to get home tests to see their progress toward testing negative for whatever reason. The gov’mt aint going to do this kind of study…. Only by doing the same type of data collection for each person can we inform ourselves of real data. Then send it in to a particular website (which does not exist at this time), and the data would be viewed and put into results that informs us with much more specific information. I would be willing to write it up exactly like a standard drug study. That was my job at one time – Regulatory documents and Medical Writing, which for any that may not know, is taking the actual suveys that patients in the study filled out and putting into a format that drug companies submit to the FDA to prove whatever results. No One else will do any type of study like this because there is no money in it whatsoever. Standard drug studies may only use 25-50 patients. So if that many people would be willing to chart the things listed above as well as some others, I will do data collection etc – just like the many studies I have written up for drugs that are now on the market. My specialty was drugs in the neuro-psycho-pharmacology – drugs for depression (of which I suffer), anxiety etc – drugs for people with Mental Illnesses. There is a lot of Bullsh*t about MMJ precipitating depression or schizophrenia. When I have seen what qualifies for an approved drug for a condition… Why are they developing drugs for constipation due to opiates and not some other medication – like weed. Crazy. Anyway, if anyone else is interested in being part of this type of study, hit me up and if enough people – in states where it is legal only – respond, I’ll write up a Patient Report form and post it or somehow – probably just make a website and print it off and complete it. send it back and then send it back at intervals of probably a year, given the time MMJ can stay in ones system. Study reports completed by patients included comments like : also started walking a mile every day, and even Adverse events – ex. too much edible and I as still feeling it when I went to give my speech…… Weed does have some adverse events and if this is going to be an informative and complete study – we need to record those too. Someone at my age may have breathing techniques or whatevs to “ride it out and not let them know you are high” . and unexpected visit from…. parent, employer…” run into someone at the gas station etc.anyway, cool – I am into education about weed/ MMJ so it doesn’t fall into the “scary trip” category – harken back to Reefer Madness bullsh*t.
    Protect ourselves from prison, stay legal and update info as to where laws are good and have changed… peace love and understanding…. Elvis C.

    • Hi Elvis, I’m with you on this subject matter! I’m old school, and when we can do things to help the MMJ Movement I’m all for it! BTW my name is Brenda. I’m in Michigan where it’s medically and recreationally legal to grow, smoke, transport, etc. at a certain amount and age.

  27. I’ve eaten 25-30 mgs of edibles each day for the last 2 days. I have a drug test in 6 days. What can I do to speed up the detox process? Do I have a chance of passing this urine test? Before ingesting these edibles I had not smoked any marijuana in a little over a month. I am 6’1 and 160 lbs. fast metabolism and skinny body.

  28. I never smoked but just one time on may 15 until now ive been sober will still show up on my hair i do alot of cardio and sweat alot when working out.thank you for any info

  29. I had a 5mg edible 16 days ago and take a drug test on Friday. 6’ 4” and 230lbs. Relatively active, work keeps me pretty busy. Am I good?

  30. What if someone takes the water soluble THC powder like Nevada’s Max Chill or Colorado’s Stillwater’s Ripple? If this is truly water soluble then it should leave your system in a couple days.

  31. I haven’t smoked weed in a month but recently did and had an edible yesterday, I may have a drug test in 1-2 weeks and wondering if it will be out of my system? I workout and am thin and drink water and pretty healthy, still worried tho

  32. I had 3 10mg edibles on Saturday and Sunday and have a urine drug screen on October 24th. Will I pee clean. What can I do to pass a urine test? I’m 63 and I weigh 150#. The guy in the store where we purchased the edibles said we would not test positive and I did the day after so I am worried

  33. It would be much more helpful if everyone would provide last smoked info, body stats, and if they passed or not. Asking the same questions is not helping the community.
    I’m cleansing now anticipating upcoming test. I will return with my results if I get tested.

  34. Hey I smoked weed twice early November and not since then, but ate 2 edibles one Dec.1st and one Dec.2nd. And I may have a urine test Jan. 6th. I’m about 5″4 275lbs and I eat a ton of junk food and do not exercise. Do you think I will pass?

  35. I used medical marijuana edibles 40 mg a night for about 6 months after fracturing my back. I stopped 6 weeks ago. I am 67 and am 5’7” tall and weigh 170. I have lost 35 pounds since September. I took a home urine test for THC today and it was positive. I may have to do one for the doctor in about 2-3 weeks. Any chance I will pass?

  36. i ate a eddi on the 6 of feb and i smoked on 3rd a pre roll i used to smoke carts a lot but i stopped on the last week of jan. i wight 203, i got tested on the 27 on feb and i failed when will it leave my body?

  37. I had a watermelon edible 40mg Saturday and took a drug test Tuesday am I fine ? I’m not a smoker, I end up trying it and forgot I had a drug test.

  38. I had a single chocolate edible, think 10mg almost 30 days ago, it was probably 2-4 years expired as well. I’m early 40’s, around 85kg, just had my urine test so I guess I’ll see if I have a job on the results.
    Everything I can find swings from Mayo Clinic saying 3 days, to calculators saying 21.


  39. I just tried a small bite of an edible and I’m being drug tested for my job. I’ve never done drugs of any kind and literally it was a teeny tiny taste probably they said maybe a milligram is all I would’ve gotten because it was a whole 50 mg block and it was cut into 12 pieces and I took a bite of the 12 piece so they said the very minute amount I would’ve gotten anyway I was just curious how long that would stay in my system

  40. No answers to so many questions.

    I did 10mg’s 8 days ago. I just did a drug test that goes to a lab. Will let you know tomorrow if I passed.

  41. I know you Hy ask if no answers are given???? But here goes I’ve had back surgery and metal in my back did a mytengy test they injected dye in my spinalcord and I was in chronic pain I cried myself to sleep for a week so I ate two gummy bears and a few hits off a joint about a week before I might get tested I couldn’t take the pain no more if I fail I’ll be taken off pain meds and they weren’t doing much for the pain after the test. I can’t live without due to chronic pain I’m so tired of pain Meds usually control it but not after that test! Any idea if I’ll pass?? I weigh 150, rarely ever smoke or do edibles very rare, and 5’5. Maybe someone will be kind enough to answer please

  42. Took 100mg edible, never did anything before that. I’m 145lbs, 5’0. Have a drug test coming up, I took it 7 days ago. How long will the THC stay in my system?

  43. OK, I have the opposite question. I tested positive, NG/ML. In order to keep my job I have to explain this by inadvertant gunny ingestion. Any idea how many gunnies, at what dosage, how many days before the test would explain that result?


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