Teaspoons to Milliliters Converter
1 US teaspoon is exactly 4.92892159375 milliliters. To convert teaspoons to milliliters, multiply by 4.92892159375.
Sources: NIST SP 811, NIST Handbook 44, BIPM SI Brochure Updated
Result
1 tsp = 4.92892 mL
How to convert teaspoons to milliliters
milliliters = teaspoons × 4.92892159375
1 US teaspoon is 1/3 tablespoon (1/6 US fluid ounce). 1 milliliter is one thousandth of a liter (1 cubic centimeter).
The factor 4.92892159375 is exact, not a rounded value. Nothing is rounded until you choose how many decimals to show.
Worked example: 2 tsp
- Start with the value in teaspoons: 2 tsp.
- Multiply by 4.92892159375, because 1 teaspoon = 4.92892159375 milliliters: 2 × 4.92892159375 = 9.8578431875 mL.
- Round to the precision you need: 9.86 mL to two decimals.
Teaspoons and milliliters side by side
Teaspoons to milliliters chart
Teaspoons from 0.125 to 6 converted to milliliters with the exact factor, shown to five significant digits.
| tsp | mL |
|---|---|
| 0.125 | 0.61612 |
| 0.25 | 1.2322 |
| 0.5 | 2.4645 |
| 0.75 | 3.6967 |
| 1 | 4.9289 |
| 1.5 | 7.3934 |
| 2 | 9.8578 |
| 3 | 14.787 |
| 4 | 19.716 |
| 5 | 24.645 |
| 6 | 29.574 |
milliliters = teaspoons × 4.92892159375. Factors: NIST SP 811, NIST Handbook 44, BIPM SI Brochure. unitcheck.net/cooking/teaspoons-to-milliliters/
Which cup, tablespoon and teaspoon?
All kitchen measures on this page are US customary: 1 cup is 8 US fluid ounces (236.5882365 mL), 1 tablespoon is half a fluid ounce (14.78676 mL) and 1 teaspoon is a third of a tablespoon (4.928922 mL). Cups and spoons sold in other countries can hold a different amount, so for a recipe written outside the United States check which measure the author means.
Going the other way? Use the Milliliters to Teaspoons converter.
Frequently asked questions
How many milliliters are in 1 teaspoon?
1 US teaspoon is exactly 4.92892159375 milliliters. 1 US teaspoon is 1/3 tablespoon (1/6 US fluid ounce).
How do I convert teaspoons to milliliters?
Multiply by 4.92892159375: milliliters = teaspoons × 4.92892159375. For example, 2 tsp = 9.86 mL.
How many teaspoons are in 1 milliliter?
1 milliliter is about 0.202884 US teaspoons. To go the other way, use the milliliters to teaspoons converter.
Is the tsp to mL conversion exact?
Yes. 1 US teaspoon is 1/3 tablespoon (1/6 US fluid ounce). The factor 4.92892159375 follows from the definitions, so the only rounding is in the number of decimals you display.
Sources
- NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B.8: Factors for Units Listed Alphabetically — exact factors are printed in bold in the NIST table (checked October 12, 2026)
- NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement — US customary units and their exact relationships (checked October 12, 2026)
- BIPM, The International System of Units (SI Brochure), 9th edition — defines the SI units, the prefixes and the units accepted for use with the SI