Teaspoons to ml converter

What is a teaspoon?

A teaspoon is a small unit of volume widely used in cooking, baking, and dosing of liquids. It is the smallest of the everyday spoon measures, sitting just below the tablespoon. Because the teaspoon grew out of household tableware rather than a single legal standard, its exact size depends on the region, which is why the same recipe can call for slightly different amounts of liquid in different countries.

Different types of teaspoons

1. US teaspoon (4.92892 ml): Defined in the United States as one third of a US tablespoon, or exactly 4.92892159375 ml. In everyday cooking it is usually treated as roughly 5 ml.

2. Metric teaspoon (5 ml): A deliberately rounded value of exactly 5 ml, common in countries that follow the metric system and the most convenient figure for quick mental conversions.

3. UK teaspoon (5.91939 ml): The traditional imperial teaspoon, slightly larger than both the US and the metric teaspoon.

Knowing which standard a recipe uses keeps conversions accurate, especially for small quantities where the differences matter most.

Conversion formulas

To convert teaspoons to milliliters, multiply the number of teaspoons by the volume of a single teaspoon in your chosen standard.

US tsp to ml

$\text{ml} = \text{tsp} \times 4.92892$

Metric tsp to ml

$\text{ml} = \text{tsp} \times 5$

UK tsp to ml

$\text{ml} = \text{tsp} \times 5.91939$

To go the other way and convert milliliters back to teaspoons, divide by the same factor:

$\text{tsp} = \frac{\text{ml}}{4.92892}$

Conversion table for common teaspoon sizes

The table below lists teaspoon volumes in milliliters for the US, metric, and UK standards.

Worked examples

A US teaspoon of vanilla

A recipe asks for 1 US teaspoon of vanilla extract:

$1 \times 4.92892 = 4.92892 \text{ ml}$

In practice cooks usually round this to about 5 ml.

Metric teaspoons of baking soda

A bake calls for 2 metric teaspoons of baking soda:

$2 \times 5 = 10 \text{ ml}$

Milliliters back to teaspoons

A medicine dose of 4.92892 ml needs to be measured with a US teaspoon:

$\frac{4.92892}{4.92892} = 1 \text{ tsp}$

Practical notes

1. Rounding: For most home cooking, treating a teaspoon as 5 ml is accurate enough. The 4.92892 ml US value matters mainly when scaling recipes up or measuring sensitive ingredients.
2. Liquids versus solids: This conversion describes volume, so it is exact for liquids. For dry ingredients the mass depends on the ingredient’s density, so milliliters and grams will not line up.
3. Check the source: When following an international recipe, confirm whether the teaspoon is US, metric, or UK before converting, especially for leavening agents and spices.

Frequently asked questions

How many ml are in a teaspoon?

A US teaspoon holds 4.92892 ml, a metric teaspoon holds exactly 5 ml, and a UK teaspoon holds 5.91939 ml.

Why is a US teaspoon not exactly 5 ml?

The US teaspoon is defined as one third of a US tablespoon, which works out to 4.92892159375 ml. The metric teaspoon was later set to a round 5 ml for convenience.

How do I convert ml to teaspoons?

Divide the number of milliliters by the size of your teaspoon. For a US teaspoon, divide by 4.92892; for a metric teaspoon, divide by 5.