How this instrument works
US recipe measurements form a small, fixed ladder of volume units — teaspoon, tablespoon, cup — and every step on that ladder is defined by an exact legal ratio rather than a rounded convenience figure. A US tablespoon is defined as exactly 3 teaspoons and exactly ½ US fluid ounce, and that fluid ounce in turn has an exact millilitre equivalent, so the tablespoon-to-millilitre conversion (14.7868 mL) is a precise figure, not an approximation someone measured with a graduated cylinder.
That precision matters more in baking than in most other cooking, because baking ratios — hydration, leavening, salt percentage — are sensitive to small errors compounding across a recipe, while a savory dish tolerates a 'heaping tablespoon' without consequence. Recipes written for a metric kitchen scale, or scaled recipes moving between tablespoon and millilitre measures, need the precise conversion rather than the commonly rounded 'about 15 mL' shorthand.
This instrument runs both conversions from a single tablespoon figure at once — teaspoons for recipes that call for the smaller unit, and millilitres for metric measuring or scientific-style recipe scaling — so there's no need to chain two separate lookups or memorize which rounding convention a given recipe assumes.
- Enter the amount in Tablespoons (tbsp) — fractions in quarters are accepted, matching standard US measuring spoons.
- Read Teaspoons (tsp) — the exact 3-to-1 conversion, useful for recipes or measuring sets that only go down to teaspoons.
- Read Millilitres (mL) — the precise legal US conversion, useful for metric kitchen scales or converting a US recipe abroad.
- For very small amounts (under a quarter tablespoon), measure directly in teaspoons rather than trying to eyeball a fraction of a tablespoon.
Worked example — 4 tablespoons of butter, melted
A recipe calls for 4 tablespoons of melted butter. Multiplying by 3 gives 4 × 3 = 12 teaspoons, and multiplying by 14.7868 gives 4 × 14.7868 = 59.1472 millilitres — three ways of describing the identical quantity of liquid.
A cook working from a metric kitchen scale would measure out 59.15 mL (or weigh it, since melted butter's density is close enough to water's for a quick estimate), while a cook without tablespoon-marked measuring spoons could count out 12 level teaspoons instead.
Questions
Why is 1 tablespoon 14.7868 mL and not a round 15 mL?
Because the US tablespoon is legally defined as exactly ½ US fluid ounce, and the US fluid ounce has its own exact metric definition that doesn't happen to land on a round millilitre figure. Many recipes and product labels round 14.7868 to 15 mL for convenience, and that rounding is harmless for cooking, but the exact figure matters when scaling a recipe by a large factor, where small rounding errors compound.
Is a US tablespoon the same as a UK or Australian tablespoon?
No — Australia uses a 20 mL tablespoon (4 teaspoons rather than 3), and the UK's metricated tablespoon is commonly taken as 15 mL, close to but not identical to the US figure used here. A recipe from outside the US that calls for 'tablespoons' may not convert correctly using the US ratios in this calculator, so check which country's spoon a recipe was written for before converting.
How many tablespoons are in a cup?
16 tablespoons make one US cup, following the same exact ladder of definitions — 1 cup = 16 tbsp = 48 tsp = 236.588 mL. This calculator handles the tablespoon-to-teaspoon and tablespoon-to-millilitre steps directly; for cup conversions, multiply the tablespoon figure by 16 or use this site's dedicated volume converter.
Does this conversion change for dry ingredients like flour or sugar?
No — a tablespoon is a fixed unit of volume regardless of what fills it, so the teaspoon and millilitre conversions here are identical whether you're measuring a liquid, a granulated solid, or a paste. What does change between ingredients is the weight a tablespoon holds, since flour, sugar, and butter all have different densities — this calculator handles volume only, not weight.
Why do some recipes use 'heaping' or 'level' tablespoons?
A level tablespoon is scraped flat across the top of the spoon and is the precise, reproducible measure this calculator's conversion assumes. A 'heaping' tablespoon deliberately mounds ingredient above the rim and has no fixed volume — it's an informal shorthand some older or casual recipes use for 'a bit more than level,' and it won't convert precisely by any formula since it isn't a standardized quantity to begin with.