Convert US Teaspoon to Metric Teaspoon
Convert us teaspoons to metric teaspoons instantly. 1 us teaspoon = 0.9857843187 metric teaspoon — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Metric Teaspoon to US Teaspoon converter for the reverse conversion.
Units explained
US Teaspoon
A US teaspoon is one third of a US tablespoon (4.9289 mL).
A standardized small cooking measure.
Used everywhere in US recipes and home dosing.
US cooking measure.
Metric Teaspoon
A metric teaspoon is exactly 5 milliliters.
Adopted as the standard metric small cooking measure.
Universal in metric recipes and liquid medicine dosing.
Metrication.
US Teaspoon to Metric Teaspoon conversion formula
The relationship between us teaspoons and metric teaspoons:
To convert us teaspoons to metric teaspoons, multiply the value in us teaspoons by 0.9857843187. To reverse, multiply metric teaspoons by 1.0144206811.
How to use this converter
Type a value into the calculator. The result in metric teaspoons updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Metric Teaspoon to US Teaspoon converter for the reverse direction.
Step-by-step: convert us teaspoons to metric teaspoons
- Write down the value in us teaspoons (tsp).
- Multiply that value by the factor 0.9857843187.
- The product is the equivalent value in metric teaspoons (tsp).
- To reverse, multiply the metric teaspoon value by 1.0144206811.
Worked examples
Example 1 — Convert 1 tsp to tsp:
1 × 0.9857843187 = 0.9857843187 tsp
Example 2 — Convert 100 tsp to tsp:
100 × 0.9857843187 = 98.578431875 tsp
Real-world example — Hair-width scale measurements
A 70-us teaspoon measurement (about the diameter of a human hair) is the kind of value materials engineers regularly express in adjacent micro-scale units like metric teaspoons for direct comparison across supplier datasheets.
70 tsp × 0.9857843187 = 69.0049023125 tsp
Real-world example — Paper and film thicknesses
At the thickness of office paper (roughly 3 us teaspoons), converting between sub-millimeter units is routine for packaging and printing buyers comparing quotes from metric and US suppliers.
3 tsp × 0.9857843187 = 2.9573529562 tsp
Real-world example — Plastic-film thickness alternates
A 150-us teaspoon plastic film converts cleanly to metric teaspoons — useful for packaging buyers reconciling supplier datasheets across metric and US measurement systems.
150 tsp × 0.9857843187 = 147.8676478125 tsp
US Teaspoon to Metric Teaspoon conversion table
Standard reference values for converting us teaspoons to metric teaspoons:
| US Teaspoon [tsp] | Metric Teaspoon [tsp] |
|---|---|
| 0.01 | 0.0098578432 |
| 0.1 | 0.0985784319 |
| 1 | 0.9857843187 |
| 2 | 1.9715686375 |
| 3 | 2.9573529562 |
| 4 | 3.943137275 |
| 5 | 4.9289215937 |
| 10 | 9.8578431875 |
| 20 | 19.715686375 |
| 30 | 29.5735295625 |
| 40 | 39.43137275 |
| 50 | 49.2892159375 |
| 100 | 98.578431875 |
| 500 | 492.892159375 |
| 1000 | 985.78431875 |
Frequently asked questions
How many metric teaspoons is 1 us teaspoon?
How do I convert us teaspoons to metric teaspoons?
How do I convert metric teaspoons back to us teaspoons?
How many metric teaspoons is 100 us teaspoons?
Popular volume unit conversions
Convert US Teaspoon to other volume units
Show all US Teaspoon conversions
Metric / SI (8 units)
US Customary (Liquid) (7 units)
Imperial (UK) (4 units)
Cubic (length-derived) (3 units)
Cooking / Culinary (3 units)
Sources & references
Conversion factor (1 tsp = 0.9857843187 tsp) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.