Convert US Teaspoon to Milliliter
Convert us teaspoons to milliliters instantly. 1 us teaspoon = 4.9289215938 milliliter — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Milliliter 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.
Milliliter
A milliliter is one thousandth of a liter, exactly equal to one cubic centimeter.
Formed with the SI prefix milli- applied to the liter.
The standard small-volume unit in cooking, medicine and the laboratory.
Metric prefix system.
US Teaspoon to Milliliter conversion formula
The relationship between us teaspoons and milliliters:
To convert us teaspoons to milliliters, multiply the value in us teaspoons by 4.9289215938. To reverse, multiply milliliters by 0.2028841362.
How to use this converter
Type a value into the calculator. The result in milliliters updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Milliliter to US Teaspoon converter for the reverse direction.
Step-by-step: convert us teaspoons to milliliters
- Write down the value in us teaspoons (tsp).
- Multiply that value by the factor 4.9289215938.
- The product is the equivalent value in milliliters (mL).
- To reverse, multiply the milliliter value by 0.2028841362.
Worked examples
Example 1 — Convert 1 tsp to mL:
1 × 4.9289215938 = 4.9289215938 mL
Example 2 — Convert 100 tsp to mL:
100 × 4.9289215938 = 492.892159375 mL
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 × 4.9289215938 = 14.7867647812 mL
Real-world example — Plastic-film thickness alternates
A 150-us teaspoon plastic film converts cleanly to milliliters — useful for packaging buyers reconciling supplier datasheets across metric and US measurement systems.
150 tsp × 4.9289215938 = 739.3382390625 mL
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 milliliters for direct comparison across supplier datasheets.
70 tsp × 4.9289215938 = 345.0245115625 mL
US Teaspoon to Milliliter conversion table
Standard reference values for converting us teaspoons to milliliters:
| US Teaspoon [tsp] | Milliliter [mL] |
|---|---|
| 0.01 | 0.0492892159 |
| 0.1 | 0.4928921594 |
| 1 | 4.9289215938 |
| 2 | 9.8578431875 |
| 3 | 14.7867647812 |
| 4 | 19.715686375 |
| 5 | 24.6446079688 |
| 10 | 49.2892159375 |
| 20 | 98.578431875 |
| 30 | 147.8676478125 |
| 40 | 197.15686375 |
| 50 | 246.4460796875 |
| 100 | 492.892159375 |
| 500 | 2464.460796875 |
| 1000 | 4928.92159375 |
Frequently asked questions
How many milliliters is 1 us teaspoon?
How do I convert us teaspoons to milliliters?
How do I convert milliliters back to us teaspoons?
How many milliliters 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 = 4.9289215938 mL) 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 Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.