2 min read
The 5ml Difference That Matters
The Australian tablespoon is 20 millilitres — one-third larger than the 15ml standard used in the US, UK, and Canada. For a single tablespoon the difference is trivial; for several tablespoons of a critical ingredient like baking powder, it’s large enough to affect the outcome. Almost no online conversion tool acknowledges this — KitchenConvert is one of the few that does, with a visible toggle on every tablespoon calculator.
Where It Came From
Australia’s metric transition in the 1970s set the tablespoon at 20ml, which divides evenly into the 250ml metric cup and matched existing Australian measuring equipment — internally consistent within Australia, but different from the rest of the English-speaking world on this one unit.
When It Matters Most
Leavening agents are the biggest risk: using an Australian tablespoon to measure baking powder from a recipe calibrated for 15ml adds a third more leavening, which can cause uneven rising, collapse, or a bitter, soapy taste. For forgiving ingredients like a tablespoon of oil, the difference is inconsequential.
The Practical Fix
Use three Australian teaspoons (3 × 5ml = 15ml) in place of one international tablespoon for precision ingredients, or convert to grams using our tablespoon-to-grams calculator with the Australian setting — eliminating the ambiguity entirely, since gram weights are identical everywhere.