Bouncers and convenience store operators in Ontario will no longer have to do fancy arithmetic to figure out whether a customer is old enough to buy alcohol or cigarettes, thanks to upcoming changes to the Ontario driver's licence.

As of Jan. 1, 2013, driver's licences and photo cards will now be clearly labeled as to whether the cardholder is of age, the province announced in a statement Monday.

"The identifier will read 'age 19' followed by the exact date the card holder turns 19, all in bold letters. It will be located near the bottom of the card, beside the date of birth," the statement said.

Only cards issued Jan. 1 and later will have the identifier.

Existing cardholders who wish to have one of the new cards can request a replacement card, but will be charged a fee.

Once the new changes take effect, Quebec will be the only province without an age identifier located on the driver's licences issued in the province.