US Teaspoons to Cubic Inches (tsp to in³)

1 US teaspoon equals 0.30078125 cubic inches exactly.

1 US teaspoon = 0.30078125 cubic inches

How to convert US teaspoons to cubic inches

To convert US teaspoons to cubic inches, multiply the number of US teaspoons by 0.30078125. This factor is exact. To go the other way, multiply cubic inches by 3.324675325 (rounded).

cubic inches = US teaspoons × 0.30078125

Example: 10 US teaspoons = 3.0078125 cubic inches.

Pints, quarts, gallons and fluid ounces differ between the US and the UK. Units are labeled 'US' or 'imperial' to avoid confusion.

About these units

US Teaspoon (tsp)

US customaryCurrent unit

One sixth of a US fluid ounce, exactly 4.92892159375 mL. Commonly rounded to 5 mL in recipes.

Teaspoons arrived with tea. Small spoons were common in Europe from at least the 13th century, and the earliest cited mention of a teaspoon is a London Gazette advertisement from 27 December 1686. Britain's Commutation Act of 1784 cut the tea tax from 119 percent to 12.5 percent, tea became cheap, and cups and spoons grew with it. By the 1850s the culinary teaspoon had settled as one third of a tablespoon.

The US teaspoon is one sixth of a US fluid ounce, exactly 4.92892159375 milliliters, though for nutrition labels and medicine it is rounded to 5 mL. Apothecaries once called the small spoon cochleare minus, to distinguish it from the larger cochleare majus. Household spoons are poor measuring tools: one study of 71 kitchen teaspoons found volumes from 2.5 to 7.3 milliliters, which is why dosing instructions point to standard measuring spoons or syringes.

1 US teaspoon = 0.004928921594 liters (approximately).

Sources: Wikipedia: Teaspoon; NIST SP 811, Appendix B.8: conversion factors for volume; 21 CFR 101.9: nutrition labeling household measures

Cubic Inch (in³)

US & ImperialCurrent unit

Exactly 16.387064 mL. Used for engine displacement in the US and for small mechanical parts.

Cubic inch is a unit defined by a ruler. Take an inch, build a cube, and its volume is exactly 16.387064 milliliters under the modern definition of the inch as 25.4 millimeters. Its main role in history is as the building block behind other US volumes: the US gallon is defined as 231 cubic inches, so a cubic inch is exactly 1/231 of a gallon. Even the 42-gallon oil barrel works out to precisely 9,702 of them.

The cubic inch survives most visibly in American engines, which are abbreviated c.i.d. for cubic inch displacement, while the rest of the world and many modern automakers speak in liters. A 5.7 liter engine is about 350 cubic inches, a conversion made easy by the exact factor of 16.387064. Small mechanical parts are also sized in cubic inches in North America.

1 cubic inch = 0.016387064 liters (exactly).

Sources: Wikipedia: Cubic inch; NIST SP 811, Appendix B.8: conversion factors for volume

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