This converter changes milliliters (mL) into US teaspoons (tsp) and back again, updating live as you type. It is handy for cooking and liquid medicine doses that mix metric millilitres and teaspoons.
How it works
A US teaspoon is defined as exactly 4.92892159375 mL, so the converter uses that fixed factor:
- tsp = mL ÷ 4.92892
- mL = tsp × 4.92892
The relationship is linear and bidirectional — type in either field and the other updates instantly. Note this is the US teaspoon; a metric teaspoon is exactly 5 mL, very close but not identical.
US teaspoon vs. metric teaspoon — why this matters for medicine
The difference between a US teaspoon (4.92892 mL) and a metric teaspoon (exactly 5 mL) is small — about 1.5% — but it matters in two specific contexts:
Medicine: UK and Australian prescription labels and medical guidance use the metric teaspoon (5 mL). US over-the-counter medicine labels may reference the US teaspoon. This converter uses the US teaspoon definition, which is correct for most US recipe and US-labelled medicine contexts. If you are converting a dose from a non-US prescription, confirm which teaspoon definition applies.
Cooking precision: For most recipes the 1.5% difference is irrelevant — a pinch of salt or a teaspoon of vanilla will not be affected. For baking recipes where liquid ratios are critical (such as bread or pastry), using a proper measuring spoon is more reliable than any conversion; the spoon itself is the standard.
Reference table
| Milliliters (mL) | US teaspoons (tsp) |
|---|---|
| 1.25 mL | 0.254 tsp (¼ tsp dose) |
| 2.5 mL | 0.507 tsp (½ tsp dose) |
| 5 mL | 1.014 tsp |
| 7.5 mL | 1.521 tsp |
| 10 mL | 2.029 tsp (2 tsp dose) |
| 15 mL | 3.043 tsp (1 tbsp) |
| 30 mL | 6.086 tsp (1 fl oz) |
Common scenarios
Liquid medicine doses: US medicine bottles often give doses in teaspoons (1 tsp, 2 tsp) but the measuring cup included in the box is marked in milliliters. The most common prescription dose is 5 mL (approximately 1 tsp) or 10 mL (approximately 2 tsp). This converter gives the exact figure so you can use a graduated oral syringe with confidence.
Scaling baking recipes: A recipe calls for 1 teaspoon of baking powder but your digital scale weighs in grams and you want to measure by volume from a ml-marked measuring cup. 1 tsp = 4.93 mL, so you would fill to the 5 mL line (the slight over is negligible for leavening agents).
Doubling or halving: Scaling recipes up or down sometimes produces awkward fractions. For example, half a tablespoon (1.5 tsp) equals about 7.39 mL, which is easier to measure with a graduated syringe than with nested measuring spoons.
US to UK volume conversion note
UK recipes sometimes use a “dessertspoon” (10 mL exactly) or a metric tablespoon (15 mL exactly). Neither of these maps cleanly to US teaspoon multiples. If you are adapting a UK recipe:
- UK dessertspoon (10 mL) ≈ 2.03 US teaspoons
- UK tablespoon (15 mL) ≈ 3.04 US teaspoons
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