Tablespoons and teaspoons
The US tablespoon is half a US fluid ounce: exactly 14.78676478125 milliliters, or 3 teaspoons. Recipes use tablespoons for oil, butter, sauces and spices. Australian tablespoons are 20 mL.
The US teaspoon is a third of a tablespoon: exactly 4.92892159375 milliliters. Baking powder, salt, vanilla and medicine doses are measured in teaspoons; dosing spoons usually use a rounded 5 mL.
Worked example
Convert 1.5 tbsp: 1.5 × 3 = 4.5, so 1.5 tablespoons is 4.5 teaspoons. Likewise 2 tbsp = 6 tsp.
Estimating in your head
The factor is a short exact number, so mental math needs no rounding: multiply by 3.
Going the other way
To convert teaspoons to tablespoons, divide by 3 (or multiply by 0.333333333333). The swap button between the boxes opens that page.
How this works
tsp = tbsp × 3
1 tbsp = ≈ 0.00001478676478 m³ and 1 tsp = 0.00000492892159375 m³, both by definition, so the factor is their ratio: 3 exactly. Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
How many teaspoons are in a tablespoon?
1 tablespoon = 3 teaspoons, exactly. The value follows from the unit definitions, so it never changes.
How do I convert tablespoons to teaspoons?
Multiply by 3. For example, 2 tbsp × 3 = 6 tsp.
What is 10 tbsp in teaspoons?
10 tbsp = 30 tsp. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- NIST SP 811 Appendix B.8 — Factors for units listed alphabetically
- NIST Handbook 44 — Appendix C, General tables of units of measurement
- Wikipedia — United States customary units
Reviewed Oct 17, 2026 · test vectors fixtures/units/volume/tablespoons-to-teaspoons/