Tsp to ML formula
1 US teaspoon = 4.928921594 millilitres, and 1 millilitre = 0.2028841362 US teaspoons. 1/6 US fl oz, about 4.93 ml.
Tsp to ML chart
| US teaspoons (tsp (US)) | Millilitres (ml) |
|---|---|
| 0.125 | 0.6161 |
| 0.25 | 1.2322 |
| 0.5 | 2.4645 |
| 0.75 | 3.6967 |
| 1 | 4.9289 |
| 1.5 | 7.3934 |
| 2 | 9.8578 |
| 2.5 | 12.3223 |
| 3 | 14.7868 |
| 4 | 19.7157 |
| 5 | 24.6446 |
| 6 | 29.5735 |
| 8 | 39.4314 |
| 10 | 49.2892 |
Values are rounded to 4 decimal places. The converter above shows more precision.
Worked examples
Half a teaspoon of baking soda
0.5 tsp (US) × 4.928921594 = 2.4645 ml
0.5 US teaspoons = 2.4645 millilitres. About 2.5 ml. Level the spoon with a knife; a heaped half teaspoon can hold far more.
Two teaspoons of vanilla extract
2 tsp (US) × 4.928921594 = 9.8578 ml
2 US teaspoons = 9.8578 millilitres. Almost exactly 10 ml, two thirds of a tablespoon.
Converting US teaspoons to millilitres in real life
Teaspoons measure small amounts that matter: baking soda, salt, spices, vanilla and yeast. In the kitchen, the 1.4% gap between the US teaspoon (4.93 ml) and the metric teaspoon (5 ml) makes no practical difference, so 1 tsp = 5 ml is the rule most cooks use.
Medicine is different. Kitchen spoons vary a lot in size, and using one for a liquid medicine is a common cause of dosing mistakes, especially for children. Always use the oral syringe or measuring cup that comes with the medicine and follow the dose in ml on the label. If a dose is given in teaspoons, ask a pharmacist for the ml amount. For larger kitchen measures, see tbsp to ml and cups to ml.