One U.S. teaspoon is 4.93 mL (the metric teaspoon is 5 mL). Teaspoon measurements in baking are small but matter for leavening and salt.
How to use the Teaspoons to mL Converter
- Type the number of teaspoons (US) into the Teaspoons (US) field. Decimals such as 0.5 are fine.
- Read the answer in Millilitres – it updates as you type, with no button to press.
- To convert the other way, type into Millilitres and the teaspoons (US) are recalculated.
- Press Copy results to copy both values with the page title, or Copy link to share this exact conversion.
This page converts only tsp ⇄ mL. Need a different unit? Use the general volume converter, where you can choose any “from” and “to” unit.
How it works
Both units measure volume, so they are always in the same ratio: one teaspoon (US) equals 4.9289216 millilitres. The calculator multiplies the number of teaspoons (US) you type by 4.9289216 to give millilitres, and when you type into the millilitres field it divides by the same factor to give teaspoons (US). Because the ratio never changes, doubling the teaspoons (US) always doubles the millilitres. Results are calculated at full precision and rounded only for display (up to eight decimal places, with very large or small values shown in scientific notation).
How to convert teaspoons (US) to millilitres
- Write down the value in teaspoons (US), for example 1 tsp.
- Multiply by the conversion factor 4.9289216 (because 1 teaspoon (US) = 4.9289216 mL).
- 1 × 4.9289216 = 4.9289216 mL.
- To go back from millilitres to teaspoons (US), divide by 4.9289216 – or multiply by 0.20288414.
tsp to mL conversion table
| Teaspoons (US) | Millilitres | Millilitres | Teaspoons (US) |
|---|---|---|---|
| 0.125 tsp | 0.6161152 mL | 1 mL | 0.20288414 tsp |
| 0.25 tsp | 1.2322304 mL | 2 mL | 0.40576827 tsp |
| 0.5 tsp | 2.4644608 mL | 5 mL | 1.0144207 tsp |
| 1 tsp | 4.9289216 mL | 10 mL | 2.0288414 tsp |
| 1.5 tsp | 7.3933824 mL | 20 mL | 4.0576827 tsp |
| 2 tsp | 9.8578432 mL | 50 mL | 10.144207 tsp |
| 3 tsp | 14.786765 mL | 100 mL | 20.288414 tsp |
| 6 tsp | 29.57353 mL | 1,000 mL | 202.88414 tsp |
What is a teaspoon?
A U.S. teaspoon is one third of a tablespoon, about 4.93 mL; the metric teaspoon is 5 mL. For medicines always use the measuring device supplied.
What is a millilitre?
A millilitre is one thousandth of a litre and exactly one cubic centimetre. Medicines, cosmetics, drinks and kitchen measures are labelled in mL.
Quick mental conversion
For a fast estimate, multiply teaspoons (US) by about 4.9 to get millilitres; the error is about 0.6%. Use the calculator above when you need the exact figure.
Common mistakes to avoid
Mixing u.s. and uk gallons, pints and fluid ounces, assuming a cup is always 250 ml, and treating volume and weight as interchangeable for anything except water.
Formula
1 tsp = 4.9289216 mL1 mL = 0.20288414 tspmL = tsp × 4.9289216Worked example
Inputs — Teaspoons (US): 1 tsp.
Results — Millilitres = 4.92892159 mL.
Frequently asked questions
How many mL in a teaspoon?
About 4.93 mL.
How many mL is 1/2 tsp?
About 2.46 mL.
How do I convert teaspoons (US) to millilitres?
Multiply the number of teaspoons (US) by 4.9289216. For example, 1 tsp × 4.9289216 = 4.9289216 mL.
How do I convert millilitres back to teaspoons (US)?
Divide by 4.9289216 (or multiply by 0.20288414), or simply type the value into the millilitres field above.
What is 2 tsp in millilitres?
2 tsp = 9.8578432 mL.
Is this conversion exact?
Yes. The factor comes from the official definitions of both units (NIST and the SI), so the only difference you may see is rounding in the last displayed digit.
Can I convert to other units on this page?
This page converts only between teaspoons (US) and millilitres. To pick any volume unit, use the general volume converter linked under Related calculators.
What formula does the Teaspoons to mL Converter use?
1 tsp = 4.9289216 mL.