US Teaspoons to Imperial Gallons (tsp to gal (UK))

1 US teaspoon equals 0.001084211178 imperial gallons (rounded).

1 US teaspoon = 0.001084211178 imperial gallons

How to convert US teaspoons to imperial gallons

To convert US teaspoons to imperial gallons, multiply the number of US teaspoons by 0.001084211178. The factor is rounded to 10 significant digits. To go the other way, multiply imperial gallons by 922.3295428 (rounded).

imperial gallons = US teaspoons × 0.001084211178

Example: 10 US teaspoons = 0.01084211178 imperial gallons.

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

Imperial Gallon (gal (UK))

Imperial (British)Current unit

Exactly 4.54609 liters, the volume of 10 pounds of water. Used for fuel economy in the UK (miles per gallon) and historically across the Commonwealth.

Britain unified its confusing gallons by act of Parliament in 1824. Before then, the country used separate ones for wine at 231 cubic inches, ale at 282 and corn at about 268.8. The 1824 reform replaced them with the imperial gallon, defined as the volume of ten pounds of distilled water, calculated at 277.274 cubic inches. A new definition in 1889 slightly changed that, and after the liter was restored to exactly a cubic decimeter in 1964, Canada and then the UK in 1976 adopted the exact value of 4.54609 liters.

Because the United States kept the 231-cubic-inch wine gallon, an imperial gallon is about 20 percent larger than a US gallon. That explains why a car rated at 40 miles per gallon in Britain is less impressive in American terms, since it comes to roughly 33 US miles per gallon. Ireland dropped the gallon as a primary trade unit at the end of 1993 and the UK at the end of September 1995, but it lives on in British fuel-economy figures and older recipes.

1 imperial gallon = 4.54609 liters (exactly).

Sources: Wikipedia: Gallon; UK Weights and Measures Act 1985, Schedule 1

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