What this calculator does
Turn teaspoons into milliliters, or milliliters into teaspoons, for any recipe. The teaspoon is the smallest everyday kitchen measure, used for salt, spices, baking soda, vanilla and yeast. Small amounts are where conversion mistakes hurt most in baking. If the salt or leavening (the baking soda or powder that makes dough rise) is off by a fraction of a spoon, it can change the result.
A US teaspoon is one third of a US tablespoon, or 1/6 of a US fluid ounce. That makes it exactly 4.92892159375 mL. Most metric countries use a teaspoon of exactly 5 mL. This page converts with the US value and shows you how small the gap is.
Where it's used
Why this math matters outside the classroom:
- Baking. A teaspoon of vanilla extract is about 4.93 mL.
- Metric spoons. A metric teaspoon is a round 5 mL, close enough to a US teaspoon for cooking.
- Scaling. A recipe needing 3 tsp of baking soda uses about 14.8 mL, which is 1 US tablespoon.
- Spice measures. A 2.5 mL spice measure is about half a US teaspoon.
- Spoons in a cup. Students check that 48 US teaspoons make a cup: 48 × 4.93 mL is about 237 mL.
Grade level and standards: Grades 5–6; Common Core State Standards for Mathematics 6.RP.A.3.d. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Enter teaspoons (¼ tsp is 0.25, ⅛ tsp is 0.125) or milliliters.
- Choose teaspoons to milliliters, or milliliters to teaspoons.
- Read the result and working; the table runs from ⅛ tsp to 2 tablespoons' worth.
What the inputs mean
- Value to convert
- US teaspoons for tsp → mL, or milliliters for mL → tsp.
- Direction
- The unit of the number you entered. The table follows the same direction.
Formula and method
mL = tsp × 4.92892159375 tsp = mL ÷ 4.92892159375 1 tsp = ⅓ tbsp = ⅙ US fl oz
Here tsp means US teaspoons, mL means milliliters, tbsp means US tablespoons and fl oz means US fluid ounces.
The exact US fluid ounce is 29.5735295625 mL. Dividing it by 6 gives 4.92892159375 mL. That decimal ends instead of repeating forever, so teaspoons to milliliters is exact.
Milliliters to teaspoons divides by the same number: 5 mL is 1.0144 US teaspoons.
Worked example
How many milliliters is 1 teaspoon of vanilla extract?
- 1 US tsp is exactly 4.92892159375 mL, so multiply: 1 × 4.92892159375.
- 1 × 4.92892159375 = 4.92892159375 mL.
Result: 1 teaspoon is about 4.93 mL. A 5 mL metric spoon holds about 1.4% more, which no recipe will notice.
Understanding the result
Mental shortcut: 1 tsp ≈ 5 mL. For milliliters to teaspoons, divide by 5. The shortcut is 1.4% off, smaller than the difference between a level and a slightly rounded spoonful.
Common amounts: ½ tsp ≈ 2.5 mL, ¼ tsp ≈ 1.2 mL, ⅛ tsp ≈ 0.6 mL, and 3 tsp make 1 tbsp (14.8 mL). A 15 mL amount is just over 3 US teaspoons.
Pitfall: "t" and "T" in handwritten recipes. Lower-case t usually means teaspoon and capital T tablespoon, a threefold difference. When in doubt, look for the abbreviations tsp and tbsp.
Assumptions and limitations
- “Teaspoon” means the US customary teaspoon, ⅓ of a US tablespoon.
- Measures are level.
- The metric 5 mL teaspoon is not a separate option; it differs from the US spoon by only 1.4%.
- Volume only: it does not give the weight of a teaspoon of an ingredient.
- Not a dosing tool. Liquid medicines should be measured with the syringe or cup supplied with them, never a kitchen teaspoon.
Frequently asked questions
How many mL are in a teaspoon?
A US teaspoon is exactly 4.92892159375 mL, about 4.93 mL. A metric teaspoon is exactly 5 mL.
How many teaspoons are in 10 mL?
About 2.03 US teaspoons, or exactly 2 metric teaspoons.
What are a dash and a pinch?
They are informal amounts, not standard units. Some measuring-spoon sets label a dash as ⅛ tsp and a pinch as 1/16 tsp, but recipes that use these words usually mean "a small amount to taste".
How this calculator is checked
Method: US teaspoon = ⅓ US tbsp = 1/768 US gal = 4.92892159375 mL exactly. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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