Teaspoons to Milliliters Conversion
1 US teaspoon = 4.93 ml
One US teaspoon equals 4.93 milliliters. Most recipes round this to 5 ml for simplicity, and that 1.4% difference rarely affects outcomes.
The confusion starts with different teaspoon standards. US teaspoons hold 4.93 ml. UK teaspoons used to be 3.55 ml but switched to 5 ml metric teaspoons decades ago. Australian teaspoons are 5 ml. When a British or Australian recipe calls for a teaspoon, they mean 5 ml.
For cooking, these small differences rarely matter. A splash of vanilla or a pinch of salt can vary by 20% without ruining your dish. For medicine, use the measuring device that comes with the medication. Kitchen spoons vary wildly in size.
How to Convert
Multiply teaspoons by 4.93 to get exact milliliters. For practical cooking, multiply by 5.
2 teaspoons = 9.86 ml (or 10 ml rounded) 3 teaspoons = 14.79 ml (or 15 ml rounded) 1 tablespoon = 3 teaspoons = 14.79 ml
To convert milliliters to teaspoons, divide by 4.93. For 20 ml of olive oil: 20 ÷ 4.93 = 4.06 teaspoons. Round to 4 teaspoons.
Most liquid measuring cups show both ml and teaspoons. A Pyrex cup marks 5 ml as 1 teaspoon, 15 ml as 1 tablespoon. These rounded values work fine for cooking.
Common Mistakes
Using actual teaspoons from your silverware drawer instead of measuring spoons. A dinner teaspoon can hold anywhere from 3 ml to 7 ml depending on the design. Decorative spoons with deep bowls hold more than flat modern designs.
Confusing teaspoons (tsp) with tablespoons (tbsp or T). One tablespoon equals 3 teaspoons or 14.79 ml. This triple-strength mistake turns a mild curry into a fire-breathing dragon. Always double-check abbreviations.
Not leveling dry ingredients. A heaping teaspoon of baking powder contains 6-7 ml worth of powder, not 5 ml. Level with a knife for accuracy. This matters most with leavening agents and salt.
Pro Tips
Buy a set of metal measuring spoons for $5. They nest together and last forever. Plastic ones warp in the dishwasher.
For sticky liquids like honey or molasses, spray the spoon with cooking oil first. The liquid slides right out. Or measure oil first, then honey in the same unwashed spoon.
Medicine syringes marked in ml give the most accurate small measurements. Keep a clean 10 ml syringe in your kitchen drawer for measuring vanilla extract or food coloring. More precise than spoons.
Ingredient-Specific Notes
Vanilla extract
1 teaspoon = 4.93 ml = about 4 grams. Pure vanilla extract costs $3-5 per ounce, so accurate measuring saves money. Imitation vanilla is half the strength of pure extract. Double the amount if substituting.
Salt
1 teaspoon table salt = 5.7 grams. 1 teaspoon Diamond Crystal kosher salt = 2.8 grams. 1 teaspoon Morton kosher salt = 4.8 grams. The crystal size creates huge weight differences. This is why recipes should specify salt type.
Baking powder
1 teaspoon = 4.8 grams when fresh. Old baking powder compacts and weighs more but works less effectively. Test by adding 1 teaspoon to 1/2 cup hot water. Fresh powder fizzes vigorously for 30 seconds.
Honey
1 teaspoon = 7 grams = 5 ml by volume. Honey is 1.4 times denser than water. Temperature affects flow. Warm honey pours like water. Cold honey barely moves. Microwave for 10 seconds to make measuring easier.
Oil
1 teaspoon = 4.5 grams for most cooking oils. Olive oil, vegetable oil, and canola oil have similar densities. Coconut oil depends on temperature: liquid at 76F, solid below that. Melt solid coconut oil before measuring by teaspoons.
Frequently Asked Questions
How many ml in a teaspoon?
4.93 ml in a US teaspoon, typically rounded to 5 ml. UK and Australian teaspoons are exactly 5 ml. The difference is small enough that using 5 ml as your conversion works for any recipe. For medicine, use the exact 4.93 ml figure or better yet, use the measuring device provided with the medication.
Is 5 ml the same as 1 teaspoon?
Close enough for cooking. Technically 5 ml equals 1.01 US teaspoons. The 1% difference won't affect your recipes. Professional kitchens and food manufacturers use 5 ml = 1 tsp for simplicity. Medical dosing requires more precision, so check whether the instructions mean US teaspoons (4.93 ml) or metric teaspoons (5 ml).
How many teaspoons in 15 ml?
3.04 teaspoons, which rounds to 3 teaspoons or 1 tablespoon. Since 1 tablespoon = 3 teaspoons = 14.79 ml, recipes often treat 15 ml and 1 tablespoon as equivalent. The 0.21 ml difference is less than 5 drops of liquid. For cooking purposes, 15 ml = 1 tablespoon = 3 teaspoons.
Why do US and metric teaspoons differ?
Historical accident. The US standardized its teaspoon at 1/6 fluid ounce in 1896, which equals 4.93 ml. When countries adopted the metric system, they rounded to a clean 5 ml for simplicity. The 1.4% difference seemed trivial. Now we're stuck with two standards. Most modern recipes specify which system they use, or include both measurements.
What's the most accurate way to measure small amounts?
A graduated cylinder or medicine syringe marked in ml beats measuring spoons for precision. You can read exactly 3.5 ml or 7.2 ml instead of estimating between spoon sizes. For tiny amounts under 1 ml, count drops: 20 drops of water = 1 ml. For dry ingredients under 5 grams, a er's scale that reads to 0.01g provides accuracy no spoon can match.