US Tablespoons to Cubic Inches (tbsp to in³)

1 US tablespoon equals 0.90234375 cubic inches exactly.

1 US tablespoon = 0.90234375 cubic inches

How to convert US tablespoons to cubic inches

To convert US tablespoons to cubic inches, multiply the number of US tablespoons by 0.90234375. This factor is exact. To go the other way, multiply cubic inches by 1.108225108 (rounded).

cubic inches = US tablespoons × 0.90234375

Example: 10 US tablespoons = 9.0234375 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 Tablespoon (tbsp)

US customaryCurrent unit

Half a US fluid ounce (14.787 mL), equal to 3 teaspoons.

A tablespoon was once a spoon first and a unit second. Tablespoons entered place settings around 1700, first reserved for soup, and in the 18th century apothecaries used an unofficial tablespoon of four fluid drams, or half a fluid ounce. That is the origin of the modern US definition, which turns the spoon into precisely half a US fluid ounce.

The US tablespoon is therefore 14.7868 milliliters, equal to three US teaspoons, and sixteen of them make a US customary cup. It is often treated as 15 mL, and American nutrition labels define a tablespoon as exactly 15 mL, so the two figures sit within about 1.4 percent of each other. The regional difference that matters is Australia, which uses a larger 20 milliliter tablespoon, so a recipe asking for a tablespoon of oil or baking powder can go wrong when translated across the Pacific.

1 US tablespoon = 0.01478676478 liters (approximately).

Sources: Wikipedia: Tablespoon; 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

Related conversions

See all volume units.