If you are cooking, baking, or measuring liquid medicine, knowing how many mL in a teaspoon saves you from making mistakes. It is one of the most searched kitchen measurement questions in the USA — and for good reason.
The short answer is this: 1 US teaspoon equals 4.93 ml. For everyday cooking, it is rounded to 5 ml. But there is more to know depending on where your recipe comes from and what you are measuring.
How Many mL in a Teaspoon?
This is the number you need to know fast.
According to the National Institute of Standards and Technology (NIST), 1 US customary teaspoon = 4.92892 mL. In practical use — especially for cooking and medicine dosing — this is rounded to 5 mL.
Why does this matter? Because using the wrong teaspoon size can throw off a recipe or, more critically, a medication dose. A study published in the International Journal of Clinical Practice found that household teaspoons varied between 2.5 mL and 7.3 mL — a huge difference when precision counts.
Always use a standardized stainless steel measuring spoon for the most accurate results.
Teaspoon to mL Conversion Chart
Use this chart as your go-to tsp to mL reference in the kitchen.
1/8 tsp = 0.62 mL
1/4 tsp = 1.25 mL
1/2 tsp = 2.5 mL
3/4 tsp = 3.75 mL
1 tsp = 5 mL
2 tsp = 10 mL
3 tsp = 15 mL
4 tsp = 20 mL
5 tsp = 25 mL
6 tsp = 30 mL
10 tsp = 50 mL
20 tsp = 100 mL
This chart uses the metric teaspoon value of 5 mL, which is the standard used in US cooking recipes and on nutritional labels as defined by 21 CFR 101.9.
Save or print this chart and keep it inside your kitchen cabinet for quick reference.
Must Visit: How Many mL in a Cup?
mL to Teaspoon Conversion
Sometimes you need to go the other direction — from milliliters to teaspoons.
Here is the simple formula:
mL divided by 5 = teaspoons (metric)
mL divided by 4.93 = teaspoons (US customary)
And here are the most common mL to tsp conversions people search for:
1 mL = 0.20 tsp
2.5 mL = 0.5 tsp
5 mL = 1 tsp
10 mL = 2 tsp
15 mL = 3 tsp
20 mL = 4 tsp
25 mL = 5 tsp
50 mL = 10 tsp
100 mL = 20 tsp
When does reverse conversion matter most? When measuring liquid medicine, nutritional supplements, or working with a recipe that lists ingredients in milliliters. Many US readers encounter metric measurements in online recipes from the UK, Australia, or Europe.
US Teaspoon vs Metric Teaspoon vs UK Teaspoon
This is the section most competitor blogs skip — and it is important.
Not all teaspoons are the same size. Here is the breakdown:
US customary teaspoon = 4.92892 mL
Metric teaspoon = 5 mL
UK/Imperial teaspoon = 3.552 mL
The US customary teaspoon is what most American recipes use. The metric teaspoon is used globally for cooking and medicine, and it is what appears on US nutrition labels and in pharmaceutical dosing. The UK Imperial teaspoon is smaller — about 3.55 mL — and is less commonly used today even in Britain.
Why does this difference exist? It goes back to history. When tea was introduced to England around 1660, it was expensive and rare. This meant smaller teacups and smaller teaspoons. As tea prices dropped after the Commutation Act of 1784, cup and spoon sizes grew. By the 1850s, the teaspoon had settled at one-third of a tablespoon — the same ratio used in both US and metric systems today.
What About Scant, Level, Rounded, and Heaped Teaspoons?
This is another gap that most blogs never explain.
How you fill the spoon changes the volume.
A level teaspoon is the US default — ingredient scraped flat with the top of the spoon. A rounded teaspoon has as much ingredient above the rim as below — roughly equal to 2 level teaspoons. A heaped teaspoon is loaded as high as possible and can equal 3 to 5 level teaspoons. A scant teaspoon means slightly less than a full level spoon.
When an American recipe says “1 teaspoon,” it always means level. A British recipe may mean rounded unless stated otherwise. This small difference can change your results — especially in baking where precision affects texture and rise.
Teaspoon to Tablespoon and Other Kitchen Conversions
Once you know teaspoons to mL, the rest of the volume unit system becomes easy.
3 tsp = 1 tablespoon = 15 mL
6 tsp = 2 tablespoons = 30 mL
1 tsp = 1/6 fluid ounce
1 tsp = 1/48 US cup
48 tsp = 1 US cup = 236.6 mL
1 mL = 1 cubic centimeter (cc or cm³)
1000 mL = 1 liter
Why does 1 mL = 1 cc matter? In medical and pharmaceutical settings, cubic centimeters (cc) and milliliters (mL) are used interchangeably. If a nurse or pharmacist gives you a dose in cc, you can convert it to teaspoons the same way.
The teaspoon also has deep roots in apothecaries’ measure — the old pharmaceutical system. Historically, 1 teaspoon was equal to 1 fluid dram, which was 1/8 of a fluid ounce. This unit was known in Latin as cochleare minus and was used in medicine for centuries before modern metric system standards replaced it.
FAQs
Is 1 teaspoon equal to 5 mL?
Yes — for cooking and medicine in the USA, 1 teaspoon is considered equal to 5 mL. This is the metric teaspoon standard used on US nutrition labels and in pharmaceutical dosing, as defined by the FDA under 21 CFR 101.9. The exact US customary figure is 4.92892 mL, but 5 mL is used for all practical purposes.
Is 2 teaspoons the same as 10 mL?
Yes. Since 1 teaspoon = 5 mL, two teaspoons equal exactly 10 mL. This is a common conversion for liquid medicine doses, especially for children’s medications that come with a 10 mL measuring cup.
Is 1 tablespoon equal to 5 mL?
No. 1 tablespoon = 15 mL, not 5 mL. A tablespoon is three times the size of a teaspoon. This is a very common mix-up that can affect both cooking results and medicine safety — so always double-check which unit a recipe or dosage label is using.
Is a teaspoon 15 or 20 mL?
Neither. A teaspoon is 5 mL (metric) or 4.93 mL (US customary). You may be thinking of a tablespoon, which is 15 mL, or a dessert spoon, which is approximately 10 mL. Always use a calibrated measuring spoon — never a regular cutlery spoon — when accuracy matters.
Conclusion
1 US teaspoon = 4.93 mL (or 5 mL for cooking and medicine). Keep the conversion chart handy, always use a standardized measuring spoon, and know which teaspoon standard your recipe or dosage follows — US, metric, or UK. That one small habit makes a big difference in both the kitchen and medicine cabinet.
Rehmaan Khan is a Measurement Content Researcher Specializing in MLmeasurement, Size Guides, Charts, and Simple Educational Measurement Content.