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Teaspoons to Milliliters

1 Teaspoon (US) (tsp) = 4.92892 Milliliter (ml)

Result
4.92892 ml
1 tsp = 4.92892 ml

How Many Milliliters in a Teaspoon?

One US teaspoon equals approximately 4.929 milliliters, commonly rounded to 5 ml, which is also the exact size of a metric teaspoon. This conversion matters most when precision counts — measuring medicine, spices, leavening agents like baking powder, or extracts like vanilla. A teaspoon of baking soda or salt can dramatically change the outcome of a recipe, so knowing the exact ml equivalent ensures accuracy. Whether you are using a metric dosing syringe for medicine, following a recipe with a ml-marked measuring cup, or converting between US and metric kitchen tools, this conversion is one of the most practical to know.

How to Convert Teaspoon (US) to Milliliter

  1. Start with your measurement in US teaspoons.
  2. Multiply the teaspoon value by 4.929 for an exact US conversion, or by 5 for the metric standard.
  3. The result is your measurement in milliliters.
  4. For cooking, 5 ml per teaspoon is the accepted standard and is what metric measuring spoons use.
  5. Remember the relationship: 1 teaspoon = 5 ml = 1/3 tablespoon = 1/48 US cup.

Real-World Examples

A children's medicine dose is 1 teaspoon. The syringe is marked in ml.
1 x 4.929 = 4.93 ml. Fill the syringe to the 5 ml mark, which is the standard medical teaspoon.
A recipe calls for 2.5 teaspoons of cinnamon.
2.5 x 5 = 12.5 ml. This is slightly under 1 tablespoon (15 ml).
You need 1/2 teaspoon of salt. How many ml is that?
0.5 x 5 = 2.5 ml. Most measuring spoon sets include a 1/2 tsp or 2.5 ml spoon.
A baking recipe needs 4 teaspoons of baking powder.
4 x 5 = 20 ml. This equals 1 tablespoon plus 1 teaspoon, or 4 metric teaspoons.

Quick Reference

Teaspoon (US) (tsp) Milliliter (ml)
1 4.92892
2 9.85784
5 24.6446
10 49.2892
25 123.223
50 246.446
100 492.892
500 2464.46
1,000 4928.92

History of Teaspoon (US) and Milliliter

The teaspoon takes its name from the small spoon used to stir tea, which became popular in Europe in the 17th century as tea drinking spread from China. By the 18th century, the teaspoon was being used as an informal cooking measurement. The US standardized it at one-third of a tablespoon (4.929 ml), while the metric system defined it as exactly 5 ml. The international medical community adopted the 5 ml standard because household teaspoons vary widely in size — studies have shown that actual teaspoons can hold anywhere from 2.5 ml to 7.3 ml, which is dangerous for medication dosing.

Common Mistakes to Avoid

  • Using an actual eating teaspoon to measure ingredients or medicine. Household teaspoons vary dramatically in size and are not reliable measuring tools. Always use a calibrated measuring spoon or a syringe for accuracy.
  • Confusing 4.929 ml (US teaspoon) with 5 ml (metric teaspoon). For cooking this difference is negligible, but over many teaspoons it can add up. A recipe calling for 10 teaspoons would differ by only 0.7 ml between systems.
  • Forgetting that 1/4 teaspoon measures exist for potent ingredients. A quarter teaspoon is 1.25 ml, which is the correct amount for strong spices like cayenne where even small variations change the heat level significantly.

Frequently Asked Questions

Is 5 ml the same as 1 teaspoon?
A metric teaspoon is exactly 5 ml. A US teaspoon is 4.929 ml, which is less than 1.5% different. For all cooking and medical purposes, 5 ml and 1 teaspoon are used interchangeably.
How many teaspoons are in a tablespoon?
There are exactly 3 teaspoons in 1 tablespoon, in both US and metric systems. So 1 tablespoon = 15 ml = 3 teaspoons.
Why do doctors recommend measuring medicine in ml instead of teaspoons?
Because household teaspoons vary in size from about 2.5 ml to 7.3 ml. Using an imprecise spoon for medication — especially for children — can lead to underdosing or overdosing. A marked oral syringe or dosing cup ensures you give exactly the right amount.
Quick Tip

For precise measurements of potent ingredients (baking soda, salt, cayenne, vanilla extract), always use calibrated measuring spoons rather than everyday silverware. A proper set includes 1/4 tsp (1.25 ml), 1/2 tsp (2.5 ml), 1 tsp (5 ml), and 1 tbsp (15 ml). The small investment pays for itself in consistent recipe results.