Tbsp to mL Converter

Article — Tbsp to mL Converter

Tbsp to mL: the four tablespoon standards and why they matter

One US tablespoon equals 14.787 mL. One metric tablespoon is 15 mL exactly. One imperial UK tablespoon is 17.758 mL, and one Australian tablespoon is 20 mL — a 33 percent jump that breaks recipes when ignored. Pick the right standard for your recipe's country of origin and multiply tablespoons by the matching mL value.

The converter at the top of this page lets you pick the standard explicitly, so a US recipe and an Australian recipe each return the right milliliters. The article covers where the four standards came from, which ones still appear in modern recipes, and why a kitchen drawer spoon is the wrong tool for either measurement.

What is a tablespoon?

A tablespoon is a unit of volume used in cooking, baking, and historical medication dosing. The symbol is "tbsp" or "T." It is a household-scale unit — too small for liter math, too large for a teaspoon. In modern recipes the tablespoon sits between the teaspoon (5 mL) and the cup (240 to 250 mL) as the middle volume measure in the kitchen.

The unit name comes from the actual table-service spoon used at a dinner table in 18th-century England, in contrast with the smaller tea-service spoon. Both spoon types eventually became standard kitchen measures, with the table-spoon set at three teaspoons (in most countries) or four teaspoons (in Australia). The exact mL value depends on which national standard you follow.

The tbsp to mL formula

To convert tablespoons to milliliters, multiply by the volume of one tablespoon in mL. The hard part is picking the right tablespoon — there are four standards in active use.

For the reverse direction, divide milliliters by the same factor. 100 mL is 6.76 US tablespoons, 6.67 metric tablespoons, 5.63 imperial UK tablespoons, or 5 Australian tablespoons. The same volume measure (100 mL) maps to four different spoon counts depending on which standard you use.

The four tbsp standards

Four tablespoon definitions are in active use today, with a 35 percent gap between the smallest (US, 14.787 mL) and the largest (Australian, 20 mL):

• US customary = 14.7868 mL (1/16 of a US cup, ½ of a US fluid ounce)
• Metric = 15 mL exactly (3 × 5 mL teaspoons, modern international)
• Imperial UK = 17.758 mL (5/8 of an imperial fluid ounce, pre-1970 British recipes)
• Australian = 20 mL (4 × 5 mL teaspoons, Australian metric)

The US and metric values are close enough that one tablespoon of either gets you within 1.4 percent. The Australian and imperial UK values are different enough that swapping them silently breaks a recipe. A recipe specifying "3 tablespoons of butter" yields 44 mL in the US, 45 mL in metric, 53 mL in old British recipes, and 60 mL in Australia.

Common tbsp to mL conversions

The most-searched tablespoon volumes across all four standards:

• ½ tbsp = 7.4 mL (US) / 7.5 mL (metric) / 10 mL (Australian)
• 1 tbsp = 14.79 mL (US) / 15 mL (metric) / 20 mL (Australian)
• 2 tbsp = 29.57 mL (US) / 30 mL (metric) / 40 mL (Australian)
• 3 tbsp = 44.36 mL (US) / 45 mL (metric) / 60 mL (Australian)
• 4 tbsp = 59.15 mL (US) / 60 mL (metric) / 80 mL (Australian) — this is ¼ cup
• 8 tbsp = 118.3 mL (US) / 120 mL (metric) — this is ½ US cup
• 16 tbsp = 236.6 mL (US) / 240 mL (metric) — this is 1 US cup

The Australian tbsp outlier

The Australian tablespoon at 20 mL is the source of more cross-country recipe failures than any other measurement standard. When Australia metricated in 1970, it had a choice: set the tablespoon at 3 metric teaspoons (15 mL), matching the international convention, or set it at 4 metric teaspoons (20 mL), matching the existing Australian household practice.

Australia picked 20 mL. The reason is that pre-metric Australian recipes had used 4-teaspoon "dessertspoons" for generations, and the National Measurement Institute wanted continuity with home cookbooks rather than alignment with the rest of the world. The result: every Australian recipe specifying "tbsp" requires 33 percent more volume than the same word in a US, British, or New Zealand recipe.

Tbsp to mL for medication dosing

Tablespoons used to appear on liquid medication labels. They no longer do. The FDA recommended a switch to milliliters in 2009 and made it standard for over-the-counter liquid drugs in 2016, after research found that parents dosing children's medication in teaspoons or tablespoons made errors at roughly 30 times the rate of parents using a calibrated oral syringe with mL markings.

A kitchen tablespoon — pulled from a drawer rather than a measuring set — ranges from 7 to 20 mL of usable volume. A 5-mL teaspoon dose given on a tablespoon-sized drawer spoon is two to four times the prescribed dose. The American Academy of Pediatrics and the CDC PROTECT Initiative both recommend mL-only dosing with the syringe that ships with the bottle.

Tbsp to cups, teaspoons, and fluid ounces

The US tablespoon connects cleanly to the rest of US volume:

The 3-teaspoon-per-tablespoon rule holds in the US, UK, Canada, New Zealand, and Europe. Australia breaks it: 4 Australian teaspoons (each 5 mL metric) equal 1 Australian tablespoon (20 mL). That extra teaspoon is the source of the 33 percent volume difference.

Common tbsp to mL mistakes

• tsp confused with tbsp — three times the volume. The most common kitchen and medication error. Doubling the rule: 3 tsp = 1 tbsp.
• Australian tbsp = 20 mL, not 15. An Australian recipe calling for 2 tbsp means 40 mL.
• Drawer spoon used as a tablespoon — household spoons range 7 to 20 mL of fill. Use a marked measuring spoon or scale.
• Tbsp as a weight — a tablespoon is a volume, not a mass. 1 tbsp of flour and 1 tbsp of honey have very different weights.
• Rounding US tbsp to 15 in pharmaceutical work — the 1.4 percent gap accumulates. For 16 tbsp (a US cup) the difference is 3.4 mL, which crosses dose-uniformity thresholds.
• Imperial UK tbsp in modern recipes — almost no modern UK cookbook uses the 17.76 mL imperial tablespoon. Only pre-1970 British recipes need it.