A standard teaspoon is generally treated as 5 milliliters (mL) in cooking and medicine, even though the precise US customary value is about 4.93 mL.

Quick Scoop: Core Answer

  • Most recipes, food labels, and dosing instructions round 1 teaspoon to 5 mL.
  • The exact US teaspoon is about 4.9289 mL, but this difference is usually too small to matter in everyday kitchen use.

Why You’ll Often See 5 mL

  • In nutrition labeling and many medical contexts, 1 teaspoon is defined as exactly 5 mL to keep measurements simple and consistent.
  • Many measuring spoons sold worldwide are designed so that the “1 tsp” scoop holds about 5 mL when level, not heaped.

Tiny Twist: US vs Metric

  • US customary teaspoon: about 4.93 mL when defined precisely, but commonly rounded to 5 mL in practice.
  • Metric teaspoon (used in many countries): defined as exactly 5 mL, so no rounding is needed.

Practical Tips

  • For recipes: treat 1 teaspoon as 5 mL and use a proper measuring spoon instead of a random household teaspoon for better accuracy.
  • For medicine: only use the marked dosing spoon/syringe that shows mL, never a regular kitchen spoon, since household spoons can vary a lot in size.

If you’re converting quickly in your head, you’re safe using:
1 teaspoon ≈ 5 mL for almost all everyday situations.

TL;DR: 1 teaspoon is treated as 5 mL in real-world use, even though the exact US definition is around 4.93 mL.

Information gathered from public forums or data available on the internet and portrayed here.