How this instrument works
US tablespoons are not metric units in disguise. Each holds half of one US fluid ounce, which is 1⁄128 of the US gallon, and that gallon has been exactly 231 cubic inches since Congress kept the English wine gallon of Queen Anne's 1706 statute. Britain replaced that vessel with an imperial gallon in 1824; America never did. Add the 1959 agreement fixing an inch at 25.4 mm and every step closes: 231⁄256 of a cubic inch is 14.78676478125 ml, with nothing left over.
Millilitres had their own wobble. Between 1901 and 1964 the litre meant whatever volume one kilogram of pure water occupied at its densest, making a millilitre 1.000028 cm³ instead of 1. In 1964 the 12th General Conference on Weights and Measures restored the litre as one cubic decimetre precisely, so millilitre and cubic centimetre have been interchangeable ever since. Results below are that cubic centimetre.
In daily practice these two units live in separate rooms. Millilitres run pharmacies, laboratories and most of the world's kitchens, while tablespoons survive in American recipes, behind bars — the pony pour is one fluid ounce, two spoons — and on old medicine labels. Care matters there, because tablespoons on US nutrition panels are rounded to 15 ml by FDA rule, while Australian ones hold 20 ml. This page handles neither: 14.7867647813 ml is a customary measuring-spoon tablespoon.
- Type your quantity into US tablespoons (tbsp); it opens at 2, the recipe writer's favourite number.
- Read Millilitres (ml) directly beneath — it recalculates on every keystroke, with no button to press.
- Part-spoons are welcome. Step size is 0.001, so 0.5, 1.75 or 2.25 tbsp all behave as typed.
- Working from teaspoons? Enter one third of your count, since 3 US teaspoons fill one tablespoon.
- Need millilitres back into spoons? Divide your ml figure by 14.7867647813, or nudge US tablespoons (tbsp) until Millilitres (ml) matches.
Worked example — 2 tbsp of olive oil, no spoon in sight
Your dressing calls for 2 tablespoons of olive oil, and all your kitchen drawer offers is a 50 ml graduated cylinder rescued from some chemistry set. Leave US tablespoons (tbsp) sitting at 2. Millilitres (ml) answers 29.5735295625 ml, so pour to just past that 29.5 graduation and you have beaten any spoon for accuracy.
Look again at what came back. 29.5735295625 ml is one US fluid ounce exactly, because two tablespoons are defined as an ounce. The US gallon holds 3785.411784 ml precisely; divide by 128 and every digit still lands clean. Any even count of spoons therefore converts through that same tidy ounce, which is why bartenders think in spoons and chemists never have to.
Questions
Is one tablespoon exactly 15 ml?
Not the US customary one. It holds 14.78676478125 ml, roughly 1.4% shy of 15. That 15 ml figure is a legal rounding: FDA nutrition labelling defines a tablespoon as 15 ml, and metric measuring spoons sold across Britain, Canada and Europe are manufactured to 15 ml. For one salad dressing this gap disappears; across 16 spoons — one US cup — it grows to about 3.4 ml, near enough a teaspoon of drift.
How many millilitres are in an Australian tablespoon?
Twenty, and that difference catches people out badly. Australia's tablespoon holds 20 ml — four 5 ml teaspoons rather than three — settled when the country metricated during the 1970s. An Australian cook working through a US recipe with local spoons therefore adds about 35% too much of whatever is being spooned. New Zealand, Britain and Canada all landed on 15 ml instead; only Australia stretched to 20.
Why show so many decimal places?
Because every digit is real. Cutting them short would mean choosing where to stop rather than reporting what is true. One US tablespoon is 231⁄256 of a cubic inch, and since an inch is precisely 25.4 mm that chain terminates at 14.78676478125 ml. Nothing along it is estimated or measured. Round your own answer to 14.8 ml, or to 15 ml, whenever your task allows — but rounding belongs at your end, not inside a converter.
Is a UK tablespoon the same as a US tablespoon?
Historically no. An imperial fluid ounce is 28.4130625 ml against 29.5735295625 ml for its US cousin, so an imperial half-ounce spoon works out at 14.20653125 ml — about 4% smaller. Modern British cookery sidesteps all of this by adopting a metric 15 ml tablespoon, so a current UK cookbook and a US one now differ by only a fraction of a millilitre per spoon. A Victorian receipt book does not.
Can I use this to measure liquid medicine?
Better not to. Confusion between teaspoons and tablespoons is a documented cause of paediatric overdose, and because a tablespoon is three teaspoons that mistake is threefold. Household cutlery is not a measuring instrument either; capacity varies wildly between spoon patterns. US pharmacy guidance now pushes millilitre-only dosing with a marked oral syringe. Convert here to interpret an older label, then draw your dose with a syringe.
What is a tablespoon in teaspoons, ounces and cups?
Three US teaspoons of 4.92892159375 ml each make one tablespoon; two tablespoons make one fluid ounce; 16 make a US cup of 236.5882365 ml; 32 fill a pint, and 256 fill that 231-cubic-inch gallon. Every rung on this ladder is a whole-number ratio, so halving or tripling a recipe never introduces rounding of its own — only your measuring hand does.