English · Australia / New Zealand / AU/NZ measuring guide

15 mL or 20 mL tablespoons and how to measure your recipe

Check the recipe author's measurements before adding or subtracting a teaspoon. The Australian tablespoon convention is 20 mL, but an Australian author's recipe can use 15 mL. Your measuring set may use either size too.

RESEARCH-LED GUIDE • CHECKED 9 OCTOBER 2026

Published 9 October 2026.

The useful question is therefore two questions: How many millilitres does this recipe mean by a tablespoon? How many millilitres does my spoon hold? Once you have both answers, the arithmetic is straightforward.

You can often make the intended amount with your existing spoons. A marked 5 mL teaspoon gives you a common unit: three make 15 mL, and four make 20 mL.

Start with the author and the individual recipe

Read the ingredient line and recipe notes first. If the author gives an explicit millilitre quantity, use that. If the author supplies an ingredient weight in grams, you can follow that weight without choosing a tablespoon size. Next, look for the site's conversion guide or the cookbook's measurement page.

These three familiar publishers illustrate why country alone is insufficient:

Donna Hay: the publisher's conversion page specifies a 20 mL Australian tablespoon and a 5 mL teaspoon. Use that guidance alongside the particular recipe's instructions. Donna Hay conversions.
RecipeTin Eats: in a dated answer on 31 August 2020, Nagi Maehashi said she uses 15 mL tablespoons. She also explained that she supplies specific instructions or teaspoon quantities where the difference matters. This is her published guidance, rather than a new confirmation of every recipe; always read the individual recipe's notes. RecipeTin Eats measurement answer.
Edmonds: its New Zealand measurement guide specifies a 15 mL tablespoon, a 5 mL teaspoon and level measurements. Edmonds weights and measures.

If a recipe explicitly says four teaspoons, measure four teaspoons. Do not rewrite that as “one tablespoon” unless you have checked the spoon's actual capacity.

Read the marks on the utensils

Look for 15 mL or 20 mL stamped or printed on the tablespoon. Check the teaspoon too: the examples below use one marked 5 mL. An ordinary eating spoon does not give you a known measuring volume just because you call it a tablespoon. Wiltshire's measuring guidance recommends checking the recipe's millilitres and the measuring set's stated standard. Wiltshire tablespoon guide.

Check fractional spoons separately, especially if your collection contains pieces from different sets. A half tablespoon means 7.5 mL in a 15 mL set, but 10 mL in a 20 mL set. Those figures are arithmetic, not evidence that every spoon labelled “half tablespoon” has been manufactured or marked consistently.

If the markings have worn away and you cannot establish the capacity from the maker, use a clearly marked measuring utensil instead. Guessing from the bowl's apparent size just introduces another uncertainty.

When the recipe means 20 mL and your tablespoon holds 15 mL

For one 20 mL tablespoon, measure either:

One 15 mL tablespoon plus one 5 mL teaspoon
Four 5 mL teaspoons

For two 20 mL tablespoons, the target is 40 mL. Measure two 15 mL tablespoons plus two 5 mL teaspoons, or eight 5 mL teaspoons.

These are volume calculations: 15 + 5 = 20, and 30 + 10 = 40. They do not mean “add a teaspoon to every Australian recipe tablespoon.” The extra teaspoon applies only after you establish that the recipe intends 20 mL and your tablespoon supplies 15 mL.

When the recipe means 15 mL and your tablespoon holds 20 mL

For one 15 mL tablespoon, use three 5 mL teaspoons. For two 15 mL tablespoons, use six 5 mL teaspoons, giving 30 mL altogether.

This avoids trying to eyeball three-quarters of a curved 20 mL spoon. If you have a properly marked 15 mL measure, using it directly is simpler still.

For half a recipe tablespoon, first halve the intended volume:

Half of 20 mL is 10 mL, or two 5 mL teaspoons
Half of 15 mL is 7.5 mL, or one 5 mL teaspoon plus one marked 2.5 mL measure

Use the ingredient's stated measuring method too. A level quantity and a heaped quantity are different instructions; changing units does not settle an instruction to pack, heap or loosely fill an ingredient.

Keep the percentage difference in perspective

Using 15 mL when 20 mL is intended supplies 5 mL less, or 25% below the intended volume. Using 20 mL when 15 mL is intended supplies 5 mL more, or about 33% above it. The percentages differ because the intended amount is different in each calculation.

Those percentages describe that ingredient's measured volume. They do not tell you that a finished cake will be 25% smaller, or that a sauce will taste 33% stronger. Recipe results depend on more than one spoonful, so this guide makes no prediction about how a particular dish will turn out.

Do not convert a dry ingredient's millilitres into the same number of grams. Use the author's ingredient-specific weight where available. Volume arithmetic alone cannot supply that weight.

If the recipe still does not say

Check the original source rather than a screenshot or repost that may omit the measurement notes. For a cookbook, look near the front or back for its conversions. For a website, search its own guidance or ask the author which size was intended.

If the answer remains unknown, the recipe is ambiguous. A country's usual convention can be a clue, but it cannot resolve an author-specific exception. Keep the uncertainty visible rather than converting the whole recipe on a guess.

Before starting, write a small note beside the recipe: “This tablespoon means ___ mL; my spoon holds ___ mL.” That single check tells you whether to use the spoon directly, add a marked teaspoon or measure the amount entirely in teaspoons.