How many grams in one teaspoon?

Answer 1

.211

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The teaspoon is a measure of volume (in kitchen) having 5 mL in USA. The gram is a unit for mass. They are not compatible.

You need to know the density of the material to evaluate the mass:

Mass = volume x density

.

Answer 2

1 teaspoon of pure water at room temperature weighs 5 grams.