Teaspoons to Ml
Convert any value from teaspoon to milliliter with full precision. Use the converter above for instant results, or read on for the exact formula, worked examples, common uses, and answers to frequently asked questions.
About the Teaspoon to Milliliter conversion
Volume conversions handle liquids, gases, and the capacity of containers. The metric system uses liters and milliliters, while the US customary system uses fluid ounces, cups, pints, quarts, and gallons. The UK uses a different gallon than the US, which is a frequent source of confusion in recipes and fuel calculations.
This page focuses specifically on converting teaspoon to milliliter. Use the converter above for instant results, or read on for what each unit is, the exact formula, a worked example, and answers to common questions.
Understanding teaspoon and milliliter
What is a milliliter?
The milliliter is one thousandth of a liter, equal to one cubic centimeter. It is standard for medicine doses, recipes, and small liquid measurements.
How a teaspoon compares to a milliliter
The teaspoon is the larger of the two units: one teaspoon is about 4.92892159 milliliter. Because the milliliter is smaller, the same length or quantity works out to a larger number when you measure it with that unit. Knowing which unit is larger is a quick way to sanity-check a conversion: if the numbers move in the wrong direction, the two units have probably been swapped.
Conversion formula
The exact mathematical relationship between teaspoon and milliliter is:
1 teaspoon = 4.92892159 milliliter
So to convert a value V from teaspoon to milliliter, use:
Vmilliliter = Vteaspoon × 4.92892159
To go in the opposite direction:
Vteaspoon = Vmilliliter × 0.20288414
These factors come from the international definitions published by NIST, BIPM, and ISO 80000 and are exact within their respective standard systems. The converter applies them with full floating-point precision.
Worked example
Using the formula above, here are some common values converted from Teaspoon to Milliliter:
| Teaspoon | Milliliter |
|---|---|
| 1 | 4.928922 |
| 5 | 24.644608 |
| 10 | 49.289216 |
| 25 | 123.22304 |
| 50 | 246.44608 |
| 100 | 492.892159 |
Sources and accuracy
The liter is defined as exactly 1,000 cubic centimeters, with the centimeter defined by the BIPM. The US liquid gallon equals exactly 3.785411784 L. The UK (imperial) gallon equals exactly 4.54609 L. These fixed values have been internationally standardized.
Conversion factors are cross-checked against the NIST SP 811 guide, the BIPM SI brochure, and ISO 80000, plus published historical references for older unit systems. For mission-critical work such as medical dosing, legal-for-trade measurement, aerospace, or large-scale engineering, always verify independently with the original source.
Practical tips
Never confuse US fluid ounces with UK fluid ounces — they differ by about 4%. The same applies to US and UK gallons and pints. When in doubt, the converter shows the exact factor used so you can verify the result.
Frequently asked questions
How many milliliter are in one teaspoon?
One teaspoon equals 4.92892159 milliliter. To convert, multiply your teaspoon value by 4.92892159.
Which is bigger, a teaspoon or a milliliter?
The teaspoon is bigger. One teaspoon equals about 4.92892159 milliliter.
How accurate is this teaspoon to milliliter converter?
It uses the official international conversion factors from NIST and BIPM with full double-precision floating-point accuracy. For everyday use the result is precise to many more decimal places than any practical measurement requires.
Can I convert milliliter back to teaspoon as well?
Yes. Use the swap button above to reverse the From and To fields, or change either dropdown to any unit in the volume category. The calculation runs entirely in your browser, so it also works offline once the page has loaded.