Convert Teaspoons to Milliliters – Kitchen Converter
This converter converts a quantity in teaspoons to milliliters using the standard metric relationship for a US culinary teaspoon. It is intended for kitchen recipes, general household measurements, and non-critical medication dosing conversions where spoon measures are used as a convenience.
The tool reports a mathematically exact conversion using the commonly accepted US teaspoon volume. Users should apply rounding appropriate to their use case and follow professional or legal dosing instruments for clinical or high-precision requirements.
Interactive Converter
Convert between teaspoon and milliliter with precision rounding.
Quick reference table
| Teaspoon | Milliliter |
|---|---|
| 1 tsp | 5 mL |
| 5 tsp | 25 mL |
| 10 tsp | 50 mL |
| 25 tsp | 125 mL |
| 50 tsp | 250 mL |
| 100 tsp | 500 mL |
Methodology
The conversion uses the established unit relationship for a US teaspoon: 1 teaspoon (US, customary culinary) equals 4.92892159375 milliliters. This value aligns with national metrology guidance and international unit definitions.
Where other teaspoon definitions exist (for example, a metric teaspoon often defined as exactly 5 mL), the converter documents the standard used and provides guidance on when to use the metric convenience value versus the more precise US teaspoon value.
Accuracy caveats: measuring spoons and household utensils vary in manufactured tolerance, surface tension effects can alter liquid volume readings, and dense or packed solids displace differently than free-flowing liquids. For medication or regulated dosing, use calibrated medical devices and follow institutional or regulatory guidance.
Worked examples
1 teaspoon × 4.92892159375 = 4.92892159375 mL (commonly rounded to 4.93 mL)
2 teaspoons × 4.92892159375 = 9.8578431875 mL (commonly rounded to 9.86 mL)
1/2 teaspoon × 4.92892159375 = 2.464460796875 mL (commonly rounded to 2.46 mL)
Key takeaways
Use the precise factor 4.92892159375 mL per US teaspoon for exact conversions and note the common 5 mL metric teaspoon approximation used in some recipes.
For critical applications such as medication dosing or laboratory measurement, use calibrated devices and follow NIST, ISO, and applicable regulatory guidance.
Further resources
External guidance
Expert Q&A
Is a teaspoon always 5 mL?
No. In many culinary contexts a metric teaspoon is treated as exactly 5 mL for convenience, but the precise US teaspoon volume used for scientific conversion is 4.92892159375 mL. Use 5 mL only when a recipe or source explicitly uses the metric teaspoon convention.
Can I use this converter for medication dosing?
This converter provides a mathematical conversion but is not a substitute for calibrated medical measuring devices. For medication dosing, follow prescribed instructions and use dosing devices designed and labeled for medical use. Refer to institutional protocols and regulatory guidance.
How many decimal places should I use?
Choose precision based on context: cooking usually tolerates rounding to two significant digits, laboratory work requires reporting uncertainties per metrology standards, and medication dosing should match the precision of the dosing device. Document any rounding applied.
Why might my measuring spoon give a different result?
Manufactured measuring spoons have tolerances; wear, surface curvature, and how the liquid is leveled affect the actual volume delivered. For critical work, calibrate volumetric equipment against traceable standards.
Sources & citations
- NIST Special Publication 811 (Guide for the Use of the International System of Units) — https://www.nist.gov/pml/special-publication-811
- NIST Weights and Measures Program — Reference on Units and Conversions — https://www.nist.gov/pml/weights-and-measures
- ISO — Quantities and Units (overview) — https://www.iso.org/standard/60564.html
- OSHA — General Safety and Health Regulations — https://www.osha.gov
- IEEE Standards Collection (standards governance and software quality best practices) — https://standards.ieee.org