The legal blood alcohol limit for fully licensed drivers in Ontario is 0.08%, or 80 milligrams of alcohol for every 100 milliliters of blood. If a driver exceeds this limit, they can face criminal charges, license suspension, and fines. However, drivers can still be penalized for driving with a blood alcohol level between 0.05% and 0.08%, which is called the "warm range". This is an excellent reason to stay well below the legal limit in Ontario if you might need to drive anywhere after drinking. Novice drivers, such as those with a G1 or G2 license, M1, and M2 drivers, face stricter Ontario alcohol limits. They are subject to a "zero tolerance" policy, meaning they cannot have any detectable amount of alcohol (0.00%) in their blood system while driving. Commercial vehicle drivers caught with any drugs or alcohol in their systems could face a three-day immediate roadside license suspension and up to $450 in fines.

In summary, the legal blood alcohol limit for fully licensed drivers in Ontario is 0.08%, or 80 milligrams of alcohol for every 100 milliliters of blood. However, drivers can still be penalized for driving with a blood alcohol level between 0.05% and 0.08%, and novice drivers face a "zero tolerance" policy. Commercial vehicle drivers caught with any drugs or alcohol in their systems could face a three-day immediate roadside license suspension and up to $450 in fines.