What is teaspoon (metric)?

A metric teaspoon is a volume unit equal to exactly 5 millilitres. It is a standard unit in cooking recipes and pharmaceutical dosing instructions across metric countries.

Real-world uses

The metric teaspoon (5 mL) is used in cooking recipes, pharmaceutical dosing instructions, and nutrition labelling. It is the standard dosing spoon for children's liquid medicines. Most international recipes specify teaspoon measurements assuming the 5 mL metric standard.

History

The teaspoon originated as a unit of apothecary measure in the 18th century, roughly the volume of a small spoon used to stir tea. The metric teaspoon was standardized at exactly 5 mL to align with the metric system and simplify pharmaceutical dosing.

Common mistakes

Confusing the metric teaspoon (5 mL) with the US customary teaspoon (4.929 mL) or the older Imperial teaspoon (3.55 mL). Also, using a household spoon instead of a measuring spoon—actual spoons vary widely in size.

What is US gallon?

A US gallon is a volume unit equal to 128 US fluid ounces, or approximately 3.785 litres. It is the standard unit for fuel, milk, and other liquid products in the United States.

Real-world uses

US gallons are used for fuel pricing and vehicle fuel economy (miles per gallon) in the United States. Milk, water, and paint are commonly sold in gallon containers. Pool volumes and water heater capacities are specified in gallons.

History

The US gallon is based on the English wine gallon of 231 cubic inches, which was defined by Queen Anne in 1707. When Britain adopted the Imperial gallon in 1824 (based on water weight), the US retained the older wine gallon standard.

Common mistakes

Confusing US gallons with Imperial gallons: a US gallon is about 3.785 litres while an Imperial gallon is about 4.546 litres—roughly 20% larger. This causes major confusion when comparing fuel economy between US and UK figures.

When is this conversion used?

Fuel economy, beverage volumes, and liquid measurements frequently require converting between litres and US gallons, especially for automotive and cooking contexts across different markets.

Worked examples

1 teaspoon (metric) = 0.00132086 US gallon

1 US gallon = 3.78541178 litre

How to convert teaspoon (metric) to US gallon

To convert teaspoon (metric) to US gallon, multiply the value by 0.00132086.

To convert US gallon back to teaspoon (metric), multiply by 757.0823568.

Measurement standards

The cubic metre is the SI derived unit of volume. The litre, equal to exactly one cubic decimetre (0.001 m³), is accepted by the BIPM for use alongside SI units. Both the lowercase "l" and uppercase "L" are approved symbols for the litre.

Did you know?

An Olympic swimming pool holds 2,500 cubic metres of water — about 2.5 million litres. The Amazon River discharges roughly 209,000 cubic metres per second, enough to fill 84 Olympic pools every single second.

Quick reference: teaspoon (metric) to US gallon

teaspoon (metric)US gallon
0.10.00013209
0.50.00066043
10.00132086
20.00264172
50.0066043
100.0132086
250.03302151
500.06604301
1000.13208603
2500.33021507
5000.66043013
1,0001.32086026

Common values

teaspoon (metric)US gallon
A teaspoon1 teaspoon (metric)0.00132086 US gallon
A cup of coffee50 teaspoon (metric)0.06604301 US gallon
A water bottle100 teaspoon (metric)0.13208603 US gallon
A bathtub60,000 teaspoon (metric)79.25161571 US gallon
A swimming pool (Olympic)500,000,000 teaspoon (metric)660,430.13089537 US gallon