Teaspoons to Milliliters
Convert teaspoon to milliliter instantly — type a value and read the result, with the exact formula shown.
Example
1 tsp = 4.928922 mL, 5 tsp = 24.64461 mL, 10 tsp = 49.28922 mL.
How it works
Milliliter = Teaspoon × 4.928922. Every value is converted through a single liter base unit using internationally defined conversion factors, so any from/to pair stays consistent.
Good to know
Converting teaspoons to milliliters bridges two very different measuring worlds: the spoon you scoop with in an American kitchen and the precise metric markings on a syringe, medicine cup, or European recipe. It comes up most often when you are doubling a recipe written in US units, dosing a child's liquid medication, or following baking instructions from a metric country that lists ingredients in mL rather than spoons.
The teaspoon here is the US customary teaspoon, defined as exactly one-sixth of a US fluid ounce, which works out to 4.928922 mL. The milliliter, by contrast, is pure metric — one-thousandth of a liter — and is the same everywhere in the world. That mismatch in origin is why the number is so awkward: a clean metric unit is being measured against a spoon size that was standardized around the US gallon, not the liter.
For everyday cooking, the rule of thumb is simply to treat 1 tsp as 5 mL. The real value is only about 1.4 percent smaller, so a teaspoon of vanilla or baking powder is close enough at 5 mL that no recipe will notice. To go the other way fast, remember that roughly 3 teaspoons fill 15 mL (one tablespoon), and 20 teaspoons make about 100 mL.
The most common mistake is assuming all teaspoons are 5 mL. They are not: a UK or Australian metric teaspoon is defined as exactly 5 mL, while the US teaspoon on this page is 4.928922 mL. The gap is trivial in the kitchen but matters for liquid medicine, where pharmacists and dosing devices use the exact 5 mL metric spoon — so always dose with a marked oral syringe, never a cutlery teaspoon, which can hold anywhere from 3 to 7 mL.
Frequently asked questions
How do you convert teaspoon to milliliter?
Multiply the number of teaspoons by 4.928922 to get milliliters. For example, 1 tsp = 4.928922 mL.
What is 1 teaspoon in milliliters?
1 teaspoon equals 4.928922 milliliters (1 tsp = 4.928922 mL).
How many teaspoons are in 1 milliliter?
There are 0.2028841 teaspoons in 1 milliliter.
Is this converter free and private?
Yes. It runs entirely in your browser, so your inputs never leave your device, there is no sign-up, and it works offline once loaded.
Are the conversions exact?
Conversions use internationally defined factors and are exact where the definitions are exact (for example, 1 inch = 2.54 cm). Displayed results are rounded for readability.
People also ask
How many mL is 2 teaspoons?
Two US teaspoons equal 9.857844 mL, which rounds to about 10 mL. Using the 5 mL kitchen rule, you can just call it 10 mL.
Is a teaspoon 5 mL or 4.929 mL?
A US customary teaspoon is 4.928922 mL, while the UK and Australian metric teaspoon is defined as exactly 5 mL. Most measuring spoons and medicine dosing follow the rounded 5 mL standard.
How many teaspoons are in 10 mL?
10 mL equals about 2.029 US teaspoons, so just over 2 teaspoons. In metric-spoon terms (5 mL each) it is exactly 2 teaspoons.
How many teaspoons is 15 mL?
15 mL is about 3.043 US teaspoons, essentially 3 teaspoons — which is also one US tablespoon. This is why a tablespoon is often listed as 15 mL.
How much is half a teaspoon in mL?
Half a US teaspoon is 2.464461 mL, commonly rounded to 2.5 mL. Most oral syringes have a 2.5 mL mark for exactly this dose.
Why isn't a teaspoon exactly 5 mL?
The US teaspoon was defined from the US fluid ounce (1/6 of an ounce), which predates metric standardization, giving 4.928922 mL. Metric countries later rounded their cooking teaspoon to a clean 5 mL.
How many mL in a teaspoon of medicine?
For medicine, a teaspoon is treated as exactly 5 mL, since that is the international standard for liquid dosing. Always measure with a marked syringe or cup rather than a kitchen spoon for accuracy.
How do I convert teaspoons to mL without a calculator?
Multiply the number of teaspoons by 5 for a quick estimate (1 tsp is about 5 mL). For the exact US value, multiply by 4.928922 instead.
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