How Much THC Can You Have in Your Blood When Driving?
Key takeaways
The Criminal Code sets two blood THC levels for drivers: 2 ng per mL for a summary offence with a maximum $1,000 fine, and 5 ng per mL for a serious offence with a $1,000 minimum fine. Combined with alcohol the figures are 2.5 ng of THC and 50 mg of alcohol per 100 mL. There is no medical exemption, and provinces add their own licence suspensions.
A driver commits a Criminal Code offence with 2 ng or more of THC per millilitre of blood within two hours of driving, and a more serious one at 5 ng or more. With alcohol the threshold falls to 2.5 ng of THC plus 50 mg of alcohol per 100 mL of blood. Impairment itself is an offence whatever the blood level. This page sets out the federal limits, how police test for them, the penalties, and the provincial suspensions we could confirm as of 31 October 2026. It is not legal advice. For the border and growing rules see travel, driving and growing.
What are the blood THC limits?
The Blood Drug Concentration Regulations (SOR/2018-148) set the figures that the Criminal Code uses. They were made on 26 June 2018, came into force the same day, and were last amended on 18 December 2018.
| Offence | Blood level | Where it comes from |
|---|---|---|
| Impaired to any degree by a drug | No blood level needed, no two-hour limit | Criminal Code s. 320.14(1)(a) |
| Lower THC level | 2 ng or more but under 5 ng of THC per mL, within two hours of driving | s. 320.14(4), Regulations s. 1 |
| Higher THC level | 5 ng or more of THC per mL, within two hours | s. 320.14(1)(c), Regulations s. 2 |
| THC with alcohol | 2.5 ng or more of THC per mL and 50 mg or more of alcohol per 100 mL, within two hours | s. 320.14(1)(d), Regulations s. 3 |
The two-hour window runs from the moment the person stops operating the vehicle. The Department of Justice’s page lists the same figures: 2 to 5 ng for the less serious offence, 5 ng or more for the more serious one, and the 2.5 ng and 50 mg combination.
How do police test for cannabis?
Police can demand roadside tests when they have reasonable grounds to suspect a drug is in a driver’s body and have reason to believe the person drove within the previous three hours (section 320.27). The demand can include physical coordination tests and a sample analysed by approved drug screening equipment. The Department of Justice says that for drugs, police need a reasonable suspicion first, and gives red eyes or tremors as examples of signs. Use of the oral fluid device is optional for police agencies.
A positive oral fluid result is described by the Department of Justice as strongly suggestive of recent cannabis use. It can support a demand for a drug recognition evaluation or a blood sample. A Standard Field Sobriety Test or a Drug Recognition Expert evaluation can also be required, and the evaluation is carried out at the police station. Section 320.28 lets an officer with reasonable grounds to believe a driver was impaired by a drug demand an evaluation by an evaluating officer, blood samples, or both. Refusing a demand without a reasonable excuse is its own offence under section 320.15.
What are the criminal penalties?
| Offence | Penalty |
|---|---|
| 2 ng to under 5 ng of THC | Summary conviction, maximum fine of $1,000 (s. 320.19(2)) |
| 5 ng or more, THC with alcohol, or impaired driving | On indictment up to 10 years in prison; on summary conviction a fine of up to $5,000 or up to two years less a day, or both. Minimums: $1,000 fine for a first offence, 30 days in prison for a second, 120 days for each later offence (s. 320.19(1)) |
| Refusing a demand | Minimum fine of $2,000 for a first offence |
On conviction for the higher offences or for refusal, the court must also order a driving prohibition under section 320.24: one to three years for a first offence, two to 10 years for a second, and at least three years for each later one, in addition to any prison term. We read only part of section 320.24, so we do not say what follows after a conviction for the lower 2 ng offence.
What do provinces add?
Provinces and territories have their own laws. The Department of Justice page says so but does not describe them. These are the ones whose official pages we could read:
- Ontario. An immediate 90-day licence suspension, a 7-day vehicle impoundment and a $550 penalty for a BAC of 0.08 or more, for refusing alcohol or drug testing, or for performing poorly in a Drug Recognition Expert evaluation. Ontario says cannabis penalties are the same as for alcohol-impaired driving. After a criminal conviction the page lists a licence suspension of at least one year and an ignition interlock for at least one year for a first offence, noting that some penalties changed from 1 July 2026. Drivers 21 or under, G1, G2, M1 and M2 holders and commercial drivers must have no drugs in their system.
- British Columbia. An immediate 90-day suspension where a sample shows over 5 ng of THC per mL within two hours of driving, or 2.5 ng with alcohol. RoadSafetyBC says an officer who suspects drugs have affected driving can serve a 24-hour prohibition or a 90-day prohibition. Graduated licence holders with any THC in their system face a 12-hour suspension, and the 24-month N-licence period restarts.
- Alberta. For failing or refusing a drug or alcohol test, or failing drug recognition tests, a first occurrence brings 90 days with no driving, then a 12-month suspension with an interlock option, a 30-day vehicle seizure and a $1,000 fine plus a 20% victim fine surcharge. Novice drivers face zero tolerance for any alcohol and drugs.
- Saskatchewan. The province says it takes a zero tolerance approach to drugs and driving. We could not read its suspension lengths.
- Newfoundland and Labrador. Impaired drivers face licence suspensions. Novice drivers, drivers under 22 and commercial drivers may not have any detectable cannabis.
Quebec, Manitoba, Nova Scotia, New Brunswick, Prince Edward Island, Yukon, Nunavut and the Northwest Territories are not covered because their official pages did not open or were not read.
Do the limits differ for medical users?
The Criminal Code limits do not. The Department of Justice says the law applies to all drivers, including those with a medical authorization for cannabis, and that it contains no medical exemption. A medical user can therefore be charged for impairment or for reaching a blood level.
Some provinces treat the administrative side differently. Ontario says medical users are not subject to its zero tolerance drug requirements, yet can still face penalties and criminal charges if their ability to drive is impaired. Newfoundland and Labrador exempts a medical user who is a novice, under 22 or a commercial driver from suspension or impoundment based only on detectable THC on a roadside device, and the exemption does not cover impairment. Medical access is covered on the medical cannabis page.
Can you carry cannabis in a vehicle?
The rules we found are provincial. The Department of Justice lists consuming in vehicles among the restrictions provinces can set.
- B.C. allows up to 30 g of non-medical cannabis in its original unopened packaging, or in other packaging if it is inaccessible to the driver, such as in the trunk. Consuming is banned for the driver and any passenger, and driving is barred if you know another person present is consuming. The exception is a motor home, camper or trailer parked where camping is allowed.
- Ontario makes it illegal to transport cannabis if it is open and not in its original packaging, or if it is not packed in baggage and is readily available to anyone in the vehicle.
- Newfoundland and Labrador allows 30 g at most, in an original container with an unbroken seal or stored where the driver and passengers cannot reach it.
- Saskatchewan bans consumption in a vehicle by a driver or passenger and lists a $300 fine for possessing, consuming or distributing cannabis in a vehicle.
Taking cannabis across a border is a separate offence covered on the travel page.
How long should you wait?
Health Canada gives no specific waiting time. It says impairment can last more than 24 hours after use, that THC can affect the ability to drive safely, and that combining alcohol with cannabis greatly increases impairment. The two-hour rule in the Criminal Code describes when a blood level counts as an offence, and it does not define a safe period.
What we could not confirm
- Driving suspension, impoundment and zero tolerance rules for Quebec, Manitoba, Nova Scotia, New Brunswick, Prince Edward Island, Yukon, Nunavut and the Northwest Territories.
- Saskatchewan’s suspension and seizure lengths for drug-impaired driving.
- Vehicle storage rules for Alberta, Saskatchewan (beyond the fine) and the provinces not listed above.
- The prescribed approved drug screening equipment, its cut-off levels and whether every police service uses it.
- Subsections of Criminal Code sections 320.14 and 320.24 that we did not read, including the exceptions in subsections 320.14(6) and (7).
- Whether other provisions of the Criminal Code have changed since the pages were read.
Legal information only, not legal advice. Laws and bylaws change; confirm the current text in the official source before you rely on it. Read the full disclaimer.
Frequently asked questions
What is the legal THC limit for driving in Canada?
There are two Criminal Code levels, both measured within two hours of driving: 2 ng of THC per mL of blood or more (a summary offence with a maximum $1,000 fine) and 5 ng or more (a serious offence). Impairment to any degree is a separate offence with no blood level required.
Can I drive with THC in my system if I use medical cannabis?
The Criminal Code has no medical exemption, and the Department of Justice says the law applies to drivers with a medical authorization. Ontario and Newfoundland and Labrador exempt medical users from their zero tolerance suspensions for detectable THC alone, but not from impairment charges.
How long after using cannabis can I drive?
Health Canada gives no specific waiting time and says impairment can last for more than 24 hours after use. The Criminal Code's two-hour rule describes when a blood level counts as an offence and does not define a safe period.
Can I carry cannabis in my car?
It depends on the province. B.C. allows up to 30 g in original unopened packaging or out of the driver's reach, such as in the trunk. Ontario bars cannabis that is open and not in its original packaging, or that is readily available to anyone in the vehicle.
Sources
- Blood Drug Concentration Regulations (SOR/2018-148) — Department of Justice Canada (Justice Laws). Accessed October 31, 2026.
- Criminal Code, section 320.14 (operation while impaired) — Department of Justice Canada (Justice Laws). Accessed October 31, 2026.
- Criminal Code, section 320.15 (failure or refusal to comply) — Department of Justice Canada (Justice Laws). Accessed October 31, 2026.
- Criminal Code, section 320.19 (punishment) — Department of Justice Canada (Justice Laws). Accessed October 31, 2026.
- Criminal Code, section 320.24 (prohibition order) — Department of Justice Canada (Justice Laws). Accessed October 31, 2026.
- Criminal Code, section 320.27 (preliminary tests) — Department of Justice Canada (Justice Laws). Accessed October 31, 2026.
- Criminal Code, section 320.28 (evaluation and blood samples) — Department of Justice Canada (Justice Laws). Accessed October 31, 2026.
- Impaired Driving Laws — Department of Justice Canada. Accessed October 31, 2026.
- Frequently Asked Questions - Drug-Impaired Driving Laws — Department of Justice Canada. Accessed October 31, 2026.
- Cannabis impairment and safety risk — Health Canada. Accessed October 31, 2026.
- Impaired driving (Ontario) — Government of Ontario. Accessed October 31, 2026.
- Cannabis and driving (Ontario) — Government of Ontario. Accessed October 31, 2026.
- Cannabis and driving (B.C.) — Province of British Columbia. Accessed October 31, 2026.
- Driving while affected by drugs or alcohol (B.C.) — Province of British Columbia. Accessed October 31, 2026.
- Where you can consume cannabis (B.C.) — Province of British Columbia. Accessed October 31, 2026.
- Impaired driving penalties (Alberta) — Government of Alberta. Accessed October 31, 2026.
- Cannabis Use in Saskatchewan — Government of Saskatchewan. Accessed October 31, 2026.
- Frequently Asked Questions, Cannabis in Newfoundland and Labrador — Government of Newfoundland and Labrador. Accessed October 31, 2026.