It may be the silly season, but a just-launched app is aiming to help New Zealanders stay out of trouble with the drink drive limits.

Ora Safety has released a free calculator which combines details like your weight with how many drinks you've had .. to figure out you quickly you'll process alcohol.

Co-founder Jackson Wood says they tested the app with a few willing volunteers, who were all surprised at how little they can now drink.

He says most people thought they could have three beers .. but the app proved most people could only have a maximum of a drink per hour.