Gallons to Teaspoons

About Gallons and Teaspoons

Gallons (gal): The US gallon (3.785 L) descends from Queen Anne's 1707 wine gallon; the UK switched to a larger imperial gallon (4.546 L) in 1824, but the US kept the original definition. Common uses: US fuel sales, US milk packaging, lawn and garden chemicals, swimming pool volumes, and aquariums.

Teaspoons (tsp): Standardized at about 5 mL for cooking purposes; US legal definition is exactly 4.92892 mL, but international cooking convention uses 5 mL even in the US. Common uses: Small cooking measurements (spices, baking powder, vanilla extract), liquid medication dosing for adults (often 1 or 2 teaspoons = 5 or 10 mL).

How the conversion works

Volume conversions use US customary measure (the cup, fluid ounce, and gallon are US definitions, not imperial). 1 US cup = 236.588 mL, 1 US gallon = 3.785411784 L.

The exact relationship is teaspoons = gallons × 7.67999886e+2, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.

When this conversion matters

Converting between gallons and teaspoons comes up wherever volume measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.