Calculator
What the Teaspoon Converter does
Teaspoon Converter: 1 tsp = 4.928921594 mL, so multiply a teaspoon (US) value by 4.928921594 to get millilitre, or divide to go back. Example: 1 tsp = 4.928921594 mL.
Point it at Value, From and To and it returns Result, How it was calculated and Reverse conversion. Results refresh instantly, so trying variations costs nothing but a moment.
Two industries often use the same word for slightly different quantities. That is usually what brings people following a recipe or spec written elsewhere here.
This runs client-side, which means we never receive what you enter and could not retrieve it if asked.
The sections that follow cover the fields, the method, and one full example computed from the defaults.
What do the Teaspoon Converter fields mean?
The Teaspoon Converter uses 3 inputs. Every field is populated on load; treat those numbers as a template rather than a suggestion.
| Field | What to enter | Default |
|---|---|---|
| Value | required | 1 |
| From | choose from Millilitre (mL), Centilitre (cL), Litre (L), Cubic metre (m³), Cubic centimetre (cm³) or Cubic inch (in³) | Teaspoon (US) (tsp) |
| To | choose from Millilitre (mL), Centilitre (cL), Litre (L), Cubic metre (m³), Cubic centimetre (cm³) or Cubic inch (in³) | Millilitre (mL) |
How does the Teaspoon Converter work?
Both units are converted through volume's base unit (L), so any of the 19 units in the dropdowns can be paired in either direction without loss of accuracy.
Definitions are taken from the SI system where one exists, and from CODATA or the IAU where a unit is established by measurement. No factor is rounded before the calculation.
Worked example
These are the values the Teaspoon Converter loads by default, and the result it produces from them. This walkthrough uses the starting values, which means you can follow along without typing anything.
| Value | 1 |
|---|---|
| From | Teaspoon (US) (tsp) |
| To | Millilitre (mL) |
| Result | 4.928921594 mL |
|---|---|
| How it was calculated | 1 tsp = 4.928921594 mL, so 1 × 4.928921594 = 4.928921594 mL |
| Reverse conversion | 0.20288414 tsp (if you meant 1 mL) |
The teaspoon
The US teaspoon is exactly 4.92892159375 millilitres (one-third of a US tablespoon), and is close to, but not identical to, the 5 mL teaspoon used as the standard medical dosing measure worldwide.
Worth knowing
- Medicine dosing instructions that say "1 teaspoon" almost always mean the standardised 5 mL medical teaspoon, not the very slightly smaller US culinary teaspoon (4.93 mL): the roughly 1.4% difference is negligible for dosing purposes, which is exactly why 5 mL became the standard measuring-spoon size sold with liquid medicines.
- In cooking, 3 teaspoons equal 1 US tablespoon exactly: a relationship worth remembering when a recipe gives one unit and a measuring set only has the other.
- As with tablespoons, country-specific culinary teaspoon sizes vary slightly, but the differences are small enough that they rarely matter outside of professional baking or pharmacy contexts.
Definitions: BIPM SI Brochure · NIST reference on units
How to use it
- Enter Value.
- Pick a value for From: the options are Millilitre (mL), Centilitre (cL), Litre (L), Cubic metre (m³), Cubic centimetre (cm³) or Cubic inch (in³).
- Pick a value for To: the options are Millilitre (mL), Centilitre (cL), Litre (L), Cubic metre (m³), Cubic centimetre (cm³) or Cubic inch (in³).
- Each keystroke triggers a fresh calculation, which is cheap because it happens locally.
- You get Result, How it was calculated and Reverse conversion back.
- Share the link rather than a screenshot. It carries the values with it.
What this tool does not do
- Repeated conversions compound rounding, so convert once from the original value where you can.
- Conversion factors use SI definitions; some industries use their own rounded factors.
- It cannot detect a typo that happens to fall inside the valid range.
- Results are only as good as the inputs. Check your units before reading anything into the output.
Frequently asked questions
Value, From and To. That is the whole form. Each field is pre-filled with a sensible default, which makes it easy to isolate the effect of a single variable.
With the values loaded when the page opens, result comes out as 4.928921594 mL. Change a value and the number is recomputed on the spot.
No. Disconnect from the internet and it still works; that is the simplest proof there is no server call.
It is free to use, with no premium tier holding back the useful parts.
Reliable for the case described. Where more than one convention exists, the method section says which one is used.