Teaspoons to mL Converter

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Enter teaspoons to convert them to milliliters, using the teaspoon definition shown on your recipe, label, or instruction.

Current setting: US customary teaspoon, 4.92892159375 mL per tsp. Change it in Advanced options if your source defines 1 tsp as 5 mL.
Advanced options
Conversion settings
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How to use our Teaspoons to mL Converter

  1. Type the amount from your recipe, worksheet, label, or instruction in Teaspoon amount (tsp). You can enter 1.5, 1/2, or 1 1/2.
  2. Open Advanced options and choose the teaspoon definition used by your source. Keep US customary for most US recipes unless the source states 5 mL.
  3. Choose the number of Result decimal places that fits your measuring tool or assignment.
  4. Select Calculate. Check that the result names the same teaspoon definition as your source before you measure or record the answer.
Example inputs for Teaspoons to mL Converter
Example inputs for Teaspoons to mL Converter

Definitions

Teaspoon (tsp): A unit of volume used in recipes, instructions, and some product labels.

Milliliter (mL): A metric unit of volume equal to one thousandth of a liter.

US customary teaspoon: The teaspoon definition used for the US customary setting. This converter uses 4.92892159375 mL per teaspoon.

5 mL teaspoon: A teaspoon definition equal to 5 mL, used in metric instructions and on some medicine labels.

Mixed number: A whole number plus a fraction, such as 1 1/2.

Common mistakes and quick fixes

Mistake: Typing more than one amount, such as "1 1/2 3".
Fix: Check Teaspoon amount and then recalculate. Enter one decimal, fraction, or mixed number only.

Mistake: Entering a fraction with zero on the bottom, such as "1/0".
Fix: Check Teaspoon amount and then recalculate. Use a fraction with a denominator greater than zero.

Mistake: Leaving the setting on US customary when a label defines 1 tsp as 5 mL.
Fix: Check Teaspoon amount and then recalculate. Choose "5 mL teaspoon (metric or medicine label)" before calculating.

Mistake: Measuring medicine with an ordinary household spoon.
Fix: Check Teaspoon amount and then recalculate. Follow the product label and use the specified oral syringe, cup, or other calibrated dosing device.

Mistake: Treating extra displayed digits as extra measuring accuracy.
Fix: Check Teaspoon amount and then recalculate. Use decimal places that match the markings on your measuring device.

Limitations & Key Assumptions / Boundary Conditions

  • The selected teaspoon definition controls the answer. A US customary teaspoon and a 5 mL teaspoon are close but not exactly the same volume.
  • This converter changes volume only. It cannot convert teaspoons to grams because the weight of a teaspoon depends on the ingredient.
  • Changing decimal places changes only the displayed answer. The calculation keeps the unrounded value.
  • For medicine, follow the product label and use the volume and calibrated dosing device it specifies. A household spoon is not a calibrated medicine measuring device.
  • The amount field accepts one nonnegative decimal, fraction, or mixed number. It does not accept ranges, equations, or multiple amounts.

Methodology

Calculation method

The converter uses the teaspoon definition you choose and does not guess it from the amount. A US customary teaspoon uses 4.92892159375 mL per tsp, while the metric or medicine setting uses 5 mL per tsp.

milliliters = teaspoon amount times selected mL per tsp factor

Worked example

For 1 1/2 teaspoons using the US customary setting, the calculation is 1.5 times 4.92892159375 = 7.393382390625 mL. With 3 result decimal places, the displayed answer is 7.393 mL.

Displayed precision

The converter rounds only after calculating the full result. More displayed decimal places do not make a spoon, cup, syringe, or other measuring device more precise.