Free teaspoons to ml calculator
Enter teaspoons — this teaspoons to mL converter applies the exact NIST factor (1 US tsp = 4.929 mL) and notes the metric (5 mL) and UK (3.55 mL) teaspoon differences, updated live, as you type.
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Volume-to-weight conversions are approximate and vary by ingredient brand, moisture, and packing method.
Results are estimates. Consult a professional.
How the teaspoons-to-mL calculator works
The US teaspoon has an exact metric equivalent defined by NIST: 1 US teaspoon = 4.92892 mL. Multiply any teaspoon quantity by that factor and you have the millilitre volume. The calculation is the same for every ingredient — millilitres measure volume, not weight, so density plays no role here. The only complication is that "teaspoon" is not a universal size: US, UK and metric teaspoons all differ.
Worked example: converting vanilla extract for a metric recipe
An Australian recipe calls for 5 mL vanilla extract. You are in the US and measuring with teaspoons. Is that exactly 1 teaspoon, or a bit more?
US teaspoons to millilitres
The table below gives exact mL for common US teaspoon quantities alongside the metric teaspoon equivalent (5 mL per metric tsp) for comparison. Millilitre values are rounded to two decimal places.
| US Teaspoons | mL (US tsp) | Metric tsp (5 mL) |
|---|---|---|
| ¼ | 1.23 | 0.25 |
| ½ | 2.46 | 0.49 |
| ¾ | 3.70 | 0.74 |
| 1 | 4.93 | 0.99 |
| 1½ | 7.39 | 1.48 |
| 2 | 9.86 | 1.97 |
| 3 | 14.79 | 2.96 |
| 4 | 19.72 | 3.94 |
| 6 | 29.57 | 5.91 |
Source: NIST SP 811. 1 US teaspoon = 4.92892 mL. 1 metric teaspoon = 5 mL exactly (Australia, Canada, South Africa). 1 traditional UK teaspoon ≈ 3.55 mL — significantly smaller, rarely used in modern British recipes.
Tips for teaspoon-to-mL conversions in the kitchen
The teaspoon-to-mL conversion is straightforward, but the existence of three different teaspoon sizes causes real confusion when cooking from international recipes. These five tips cover the most common situations.
- Australian and South African recipes use 5 mL teaspoons — The metric teaspoon is exactly 5 mL (not 4.929 mL). For most ingredients the 0.07 mL gap is trivial, but when a recipe says "1 tsp baking powder" using an Australian cookbook, the expected amount is precisely 5 mL, not 4.93 mL. For sensitive chemistry like leavening, this can matter.
- Liquid medicines are measured in metric teaspoons — Dosage instructions on children's medicine bottles use the metric teaspoon (5 mL exactly), not the US teaspoon (4.93 mL). Always use the dosing syringe or spoon that comes with the medicine, never a cooking teaspoon.
- A teaspoon pour isn't really a teaspoon — Pouring liquid into a teaspoon from a bottle and eyeballing it introduces 10–20% error. For vanilla extract, food colouring and liquid flavourings, draw up with a measuring syringe or use a set of dry-measure spoons that you fill precisely to the rim.
- Know the spoon chain for quick conversions — 1 US tablespoon = 3 US teaspoons = 14.79 mL. 1 US cup = 48 US teaspoons = 236.6 mL. If you need 15 mL and don't have a metric tablespoon, use 3 US teaspoons (14.79 mL) — the 0.2 mL difference is negligible.
- Syringes are the most accurate tool for small liquids — A 5 mL or 10 mL oral syringe (sold at pharmacies) is marked in 0.5 mL increments and far more accurate than spoon measures for things like vanilla, liquid stevia, hot sauce or liquid rennet where small volumes matter.
Accuracy and limitations
The conversion factor 1 US teaspoon = 4.92892 mL is the exact NIST-defined value. Results displayed are rounded to two decimal places; the unrounded figure is 4.928921593... mL per teaspoon. There is no ingredient-specific density involved — millilitres measure volume, so the same factor applies to water, oil, vanilla extract, vinegar and anything else measured by the teaspoon.
This calculator uses US teaspoons by default and also shows metric teaspoon (5 mL) equivalents. It does not convert the traditional UK teaspoon (≈ 3.55 mL) or the now-obsolete apothecary teaspoon (3.70 mL). Modern British recipes use metric millilitres or the 5 mL metric teaspoon rather than the traditional UK measure, so the UK teaspoon is rarely encountered outside of historical recipes.
Teaspoon and volume terms defined
About this teaspoons-to-mL calculator
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