# Teaspoons to mL Converter URL: https://speedycalculator.com/calculators/conversion/tsp-ml-converter/ Last updated: 2026-10-25 > Convert teaspoons (US) (tsp) to millilitres (mL): 1 teaspoon (US) = 4.9289216 mL, so multiply by 4.9289216 or divide by 0.20288414. Both fields are editable, so you can also type in millilitres and get teaspoons (US) back. ## Inputs - Teaspoons (US) (tsp) ## Results - Millilitres ## Formula ``` 1 tsp = 4.9289216 mL 1 mL = 0.20288414 tsp mL = tsp × 4.9289216 ``` ## Explanation 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)MillilitresMillilitresTeaspoons (US)0.125 tsp0.6161152 mL1 mL0.20288414 tsp0.25 tsp1.2322304 mL2 mL0.40576827 tsp0.5 tsp2.4644608 mL5 mL1.0144207 tsp1 tsp4.9289216 mL10 mL2.0288414 tsp1.5 tsp7.3933824 mL20 mL4.0576827 tsp2 tsp9.8578432 mL50 mL10.144207 tsp3 tsp14.786765 mL100 mL20.288414 tsp6 tsp29.57353 mL1,000 mL202.88414 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. ## Worked example Inputs — Teaspoons (US): 1 tsp. Results — **Millilitres = 4.92892159 mL**. ## FAQ **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. ## Sources - [NIST Special Publication 811 – Guide for the Use of the International System of Units](https://www.nist.gov/pml/special-publication-811) - [NIST Handbook 44 Appendix C – General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)