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Below the primary result, a grid shows the same value converted to every other supported unit, so you can cross-check at a glance.
Every volume unit is converted through litres (L) as the base. The input value is multiplied by the FROM factor to get litres, then divided by the TO factor to produce the result. Keeping a single base unit makes the math internally consistent and reversible for any unit pair.
litres = value × factor(from) | result = litres / factor(to)
1 US gallon = 3.78541 L, 1 UK (imperial) gallon = 4.54609 L — they are NOT the same, the UK gallon is ~20% bigger
US liquid ounce ≠ UK fluid ounce — US = 29.5735 mL, UK = 28.4131 mL (the UK one is smaller)
Kitchen shortcut: 1 US cup = 16 tablespoons = 48 teaspoons = 240 mL
1 litre = 1,000 cm³ = 1,000 mL — this is an exact definition, unlike most imperial conversions
1 oil barrel (bbl, petroleum) = 42 US gallons = 158.987 L — used in crude oil pricing
1 cubic foot = 7.48052 US gallons ≈ 28.3168 L — useful for tank and aquarium sizing
A wine bottle (750 mL) is about 25.36 US fl oz or just over 3 US cups
Volume measurement is complicated by the coexistence of three major systems: metric (liters and milliliters), US customary (gallons, quarts, cups, fluid ounces), and imperial (which shares names with US units but differs in size). A US gallon equals 3.785 liters, while an imperial gallon is 4.546 liters — nearly 20% larger. Even within the US system, a "cup" varies by context: a US legal cup (used in nutrition labeling) is 240 mL, while a US customary cup is 236.588 mL. In cooking, these small differences rarely matter, but in chemistry, pharmacy, and industrial applications, precision is critical. The metric system's decimal structure makes conversion straightforward (1 liter = 1,000 mL = 0.001 cubic meters), while converting between US customary units requires memorizing that 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces. Scientific and engineering applications use cubic meters (m³) as the SI standard, with cubic centimeters (cm³, identical to mL) common in medicine and automotive contexts (engine displacement). International recipes, pharmaceutical dosing, and global trade all require reliable volume conversion to avoid potentially costly or dangerous measurement errors.
Metric volumes (mL, L, cm³, m³) are clean powers of 10: 1 L = 1,000 mL = 1,000 cm³, 1 m³ = 1,000 L. US customary volumes for liquids follow a ladder: 1 US gal = 4 qt = 8 pt = 16 cups = 128 fl oz. UK (Imperial) volumes use the same names but different sizes: 1 UK gal = 4.54609 L ≈ 20% larger than a US gallon. Our converter keeps US and UK units clearly labelled so you never mix them up accidentally.
The most-searched cooking conversions: 1 US cup = 240 mL = 16 tbsp = 48 tsp, 1 US tbsp = 3 tsp = 14.7868 mL, 1 US tsp = 4.92892 mL. 1 US fl oz = 29.5735 mL, so an 8 oz glass = 236.6 mL. For metric recipes: 250 mL ≈ 1.06 US cups, 500 mL ≈ 16.9 US fl oz, 1 L ≈ 4.23 US cups.
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All formulas verified against official standards.