Oz to Liters conversion

Fluid ounces to liters

Liters are the natural unit for anything bigger than a glass — bottles, jugs, fuel, aquariums — while American labels stay in fluid ounces well past the point where the numbers get large (a gallon jug says "128 fl oz"). One US fluid ounce is 0.0295735 liters, so fluid ounces × 0.0295735 = liters, or, more memorably, divide by 33.814.

Quick estimate

Divide the ounces by 34 for a slightly low answer, or by 33 for a slightly high one. 64 fl oz is just under 2 liters (1.89 L); 100 fl oz is just under 3 liters (2.96 L).

• 8 fl oz = 0.24 L
• 16 fl oz = 0.47 L (a US pint)
• 32 fl oz = 0.95 L (a US quart)
• 33.8 fl oz = 1 L
• 50 fl oz = 1.48 L
• 64 fl oz = 1.89 L (half a gallon)
• 100 fl oz = 2.96 L
• 128 fl oz = 3.79 L (a US gallon)

Water bottles and hydration

Reusable bottles are marketed as 20 oz, 32 oz or 40 oz; in liters that is 0.59, 0.95 and 1.18 L. Hydration guidelines expressed as "eight 8-ounce glasses" add up to 64 fl oz, about 1.9 L per day.

Engines, pools and gardens

Motor oil is sold in quarts (32 fl oz = 0.95 L) in the US and in 1 L bottles elsewhere — close, but a 5-quart oil change is 4.7 L, not 5 L. Concentrated garden and pool chemicals list dilution rates in ounces per gallon; converting both to liters (1 fl oz per gallon = 7.8 ml per liter) makes the maths easier with a metric measuring cup.

US and imperial ounces

The imperial fluid ounce is 28.41 ml, 4 % smaller than the US one, and the imperial gallon has 160 of them rather than 128. Old British recipes and Canadian labels may use imperial ounces; everything sold in the United States uses the US ounce assumed on this page.