A US teaspoon is one third of a US tablespoon.
Teaspoons to Metric teaspoons Converter — tsp to metric tsp
Convert Teaspoon (tsp) to Metric teaspoon (metric tsp) using the exact conversion factor (1 teaspoon = 0.9857843187 metric teaspoon). See the formula, worked examples, conversion table, and common uses.
Teaspoons to Metric teaspoons converter
Converter
Cooking Converter
Convert cooking volume and mass units used in recipes and nutrition workflows.
Context values
Some unit families need one extra value for a physically accurate result.
A metric teaspoon is 5 milliliters.
Result = input x 4.92892159e-6 / 5e-6.
Volume units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Teaspoons to Metric teaspoons
Teaspoon and Metric teaspoon both show up in recipes, and converting between them matters whenever a recipe from one country's cookbook needs to be followed with another country's measuring tools. Teaspoon is most often used for us recipe and cooking measurement for small quantities.
Formula
metric teaspoons = teaspoons × 0.98578431875
This factor comes from each unit's defined relationship to the category's base unit: 1 teaspoon equals 0.00000492892159375 base units, and 1 metric teaspoon equals 0.000005 base units, so dividing one by the other gives the direct teaspoon-to-metric teaspoon factor of 0.98578431875.
Simple example
1 tsp × 0.9857843187 = 0.9857843187 metric tsp
1 teaspoon = 0.9857843187 metric teaspoons.
Real-world example
2 tsp × 0.9857843187 = 1.971568637 metric tsp
2 teaspoons = 1.971568637 metric teaspoons.
Conversion table
| Teaspoon (tsp) | Metric teaspoon (metric tsp) |
|---|---|
| 0.25 tsp | 0.2464460797 metric tsp |
| 0.5 tsp | 0.4928921594 metric tsp |
| 1 tsp | 0.9857843187 metric tsp |
| 2 tsp | 1.971568637 metric tsp |
| 4 tsp | 3.943137275 metric tsp |
| 8 tsp | 7.88627455 metric tsp |
Reverse conversion: Metric teaspoon to Teaspoon
0.9857843187 metric tsp × 1.014420681 = 0.9999999999 tsp
0.9857843187 metric teaspoons = 0.9999999999 teaspoons.
teaspoons = metric teaspoons × 1.01442068106
For a page dedicated to this direction, see Metric teaspoon to Teaspoon.
Understanding the Teaspoon
Teaspoon (tsp) measures volume. The US teaspoon is exactly 4.92892159375 milliliters — 1/3 of a US tablespoon and 1/48 of a US cup. It is classified as a US customary unit.
Where it's used: United States (cooking and recipe measurement)
Uses of the Teaspoon today
- US recipe and cooking measurement for small quantities
- Medication dosing instructions in the US
- Baking measurement alongside the tablespoon and cup
Understanding the Metric teaspoon (metric tsp)
A metric teaspoon is 5 milliliters.
Teaspoon — sources
- NIST Handbook 44, Appendix C — General tables of units including the US teaspoon definition.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many metric teaspoons are in 1 teaspoon?
1 teaspoon equals 0.9857843187 metric teaspoons, using the exact defined conversion factor rather than an estimate.
How do I convert teaspoon to metric teaspoon?
Multiply the teaspoon value by 0.9857843187. The converter above does this instantly to whatever precision you set.
How do I convert metric teaspoon back to teaspoon?
Use the reverse factor: 1 metric teaspoon equals 1.014420681 teaspoons. You can also use the swap control in the converter above to flip the direction instantly.
What is a teaspoon?
Teaspoon (tsp) measures volume. The US teaspoon is exactly 4.92892159375 milliliters — 1/3 of a US tablespoon and 1/48 of a US cup. It is classified as a US customary unit.
What is a metric teaspoon?
Metric teaspoon (metric tsp) is a unit of cooking.
Is the teaspoon to metric teaspoon conversion exact?
Yes. The US teaspoon is exactly 4.92892159375 milliliters — 1/3 of a US tablespoon and 1/48 of a US cup. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the teaspoon still used today?
United States (cooking and recipe measurement)