What this calculator does
The teaspoon used for cooking and medicine dosing is standardised at 5 mL in Australia, the UK and on most medicine labels worldwide. The US customary teaspoon is very slightly smaller, at 4.92892 mL, close enough that it rarely matters for cooking but worth knowing when a recipe or dosing instruction specifies one system exactly.
This calculator converts teaspoons to millilitres or millilitres to teaspoons, with a choice of the 5 mL standard/medical teaspoon or the US teaspoon, so a figure like "1 teaspoon to ml" gives the precise answer for the teaspoon actually being used.
The formula
Multiply the number of teaspoons by the teaspoon size, 5 mL for the standard/medical teaspoon or 4.92892 mL for the US teaspoon, to get millilitres. To go the other way, divide the millilitre figure by the same teaspoon size.
| Term | Meaning |
|---|---|
| Standard/medical teaspoon | The 5 mL teaspoon used on Australian and UK medicine labels and in most modern recipes. |
| US teaspoon | The US customary teaspoon, 4.92892 mL, about 1.4% smaller than the 5 mL standard. |
| mL | Millilitre, the metric unit the teaspoon figure is being converted to or from. |
The inputs explained
| Field | What to enter |
|---|---|
| Convert | Choose whether you are starting from teaspoons or from millilitres. |
| Teaspoon size | Choose which teaspoon definition applies: the 5 mL standard/medical teaspoon, or the slightly smaller US teaspoon. |
| Amount | The amount to convert, in whichever unit you selected as the starting point. |
When to use it
Measuring a medicine dose
Medicine labels that say "1 teaspoon" almost always mean the 5 mL standard dose, the same size as the dosing spoon or syringe that usually comes with the bottle.
Converting a US recipe to millilitres
A US recipe measured in teaspoons converts at 4.92892 mL each rather than 5 mL, a difference too small to matter for most cooking but there for reference.
Working out how many mL a syringe dose in teaspoons needs
An oral syringe marked in mL is easiest to fill correctly when the teaspoon dose on the label is first converted to millilitres.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How many mL are common teaspoon amounts (5 mL standard)?
Common teaspoon amounts, using the 5 mL standard/medical teaspoon, converted to millilitres.
| Teaspoons | Millilitres |
|---|---|
| 0.25 tsp | 1.25 mL |
| 0.5 tsp | 2.50 mL |
| 1 tsp | 5.00 mL |
| 1.5 tsp | 7.50 mL |
| 2 tsp | 10.00 mL |
| 3 tsp | 15.00 mL |
How many mL are common mL amounts, in teaspoons?
Common millilitre doses converted to the 5 mL standard teaspoon.
Questions
How many mL is 1 teaspoon?
The standard/medical teaspoon is exactly 5 mL. The US customary teaspoon is very slightly smaller, at 4.92892 mL. Medicine labels and Australian/UK recipes almost always mean the 5 mL figure.
Is a cooking teaspoon the same as a medicine teaspoon?
Yes, in Australia and the UK: both are standardised at 5 mL. Always use an actual measuring spoon or the dosing device supplied with a medicine rather than an ordinary cutlery teaspoon, which can vary in size.
How is this different from converting mg to mL for a dose?
This calculator converts a volume unit, teaspoons, to another volume unit, millilitres. Converting a milligram dose to a millilitre volume depends on the concentration of the specific medicine, which is a different calculation; see the mg to mL calculator for that.
Why do some US recipes give a slightly different mL figure for a teaspoon?
The US teaspoon is legally defined as 4.92892 mL rather than an even 5 mL, a leftover of the US customary measurement system. The difference is small enough to ignore in most cooking.
For medicine doses that convert a milligram amount using the drug's concentration rather than a fixed spoon size, see the mg to mL calculator. For the full kitchen measures ladder, see the cooking measures converter.