How Many mL in a Tablespoon?

Aim for the 15 mL line

The converted value of a US tablespoon is 14.79 mL, but the 0.21 mL between that and 15 is about 1.4%, and a kitchen tool marked in 1 mL steps can't show you that difference anyway. One thing before going further: this page is about food. A recipe spoon isn't a way to measure medicine, and for anything medical the directions and the device that came with the product are what count, or a pharmacist if you're unsure.

Turning a recipe in mL into spoons

A recipe written in milliliters is often written in fives, and that makes the arithmetic almost free. Count the fives as teaspoons, then trade every three teaspoons for a tablespoon. Every result comes in the same 1.4% under, because that's the gap between a 5 mL teaspoon and a 4.93 mL one, so nothing here needs a percentage worked out.

• 20 mL: four fives, so 1 tablespoon + 1 teaspoon (19.72 mL)
• 35 mL: seven fives, so 2 tablespoons + 1 teaspoon (34.50 mL)
• 50 mL: ten fives, so 3 tablespoons + 1 teaspoon (49.29 mL)
• 75 mL: fifteen fives, so 5 tablespoons (73.93 mL)

Amounts between fives need a choice. Twelve milliliters is about 2½ teaspoons, 12.32 mL and 2.7% over, close enough for most things. I'd stop counting altogether at 60 mL, which is 4 tablespoons and one scoop of a ¼ cup measure, since an amount that size has no business being counted out in spoonfuls.

Is a tablespoon 15 mL or 14.79 mL?

Both numbers are in honest use. 14.79 mL is what you get converting a US tablespoon, and the FDA's guidance on household measures sets 15 mL for nutrition labels. The cooking conversion chart explains why the two conventions coexist, so I won't repeat that here. What's useful for a marked tool is how the gap behaves. It stays 1.4% at any size: 0.85 mL across 4 tablespoons and 3.41 mL across 16. If you're not going to notice 1.4% of the ingredient, and I can't think of a home recipe that would, go with the line your tool actually has. Type an amount in tablespoons above and you get milliliters to two decimals, with the nutrition-label value on its own line, so you can pick the one printed on your tool.

Syringes, small marked cups and stamped spoons

With a 5 mL food syringe, a tablespoon is three full draws, and the last column of the table counts the rest. With a 10 mL syringe, it's one full draw and one to the 5 mL line. A half tablespoon is 7.39 mL, or 7.5 by label rounding, and ¼ teaspoon is 1.23 or 1.25. These small amounts are where a syringe earns its drawer space, because a fine-marked barrel can show 1.25 mL more plainly than a tiny spoon can be judged level. For extracts, or a strong sauce added by the drop, I think the syringe is the better tool outright. Three teaspoons to the tablespoon still holds in mL, as the teaspoon page breaks down in more detail.

A small plastic cup with molded lines needs a little more care. Small amounts sit low in the cup, so set it on the counter and bring your eye down to the 15 mL line instead of holding it up and looking in from above. If the smallest line on the cup is bigger than what you need, switch tools, because guessing a fraction of the lowest mark defeats the purpose of having marks.

If the tablespoon in your set is stamped 15 mL, use it as a tablespoon in an American recipe and don't try to subtract anything. No home cook is going to shave a fifth of a milliliter off a spoon. The more useful habit is consistency: where ratios matter, measure every spoon amount in one recipe with the same set of tools, so that any small bias is at least the same small bias throughout.