How this calculator works
A litre is exactly 0.001 m3, or one cubic decimetre, and a gram is one thousandth of a kilogram. A litre of pure water at about 4 degrees Celsius is almost exactly one kilogram, so one gram of water is one millilitre and one litre is 1,000 g. Other substances differ: a litre of milk is about 1,030 g, a litre of cooking oil about 920 g and a litre of honey about 1,420 g. The page multiplies the volume by the density, or divides the mass by the density, and the preset densities are typical room temperature values.
Formula
grams = litres x density in kg/m3. Because 1 L is 0.001 m3, a density of 1,000 kg/m3 gives 1,000 g per litre. litres = grams / density. For a custom substance, grams per litre equal the density in kg/m3 directly.
Worked example
1,000 g of water at 1,000 kg/m3 is 1 L. 500 g of cooking oil at 920 kg/m3 is 0.543478 L. 1 L of milk at 1,030 kg/m3 is 1,030 g. 2.5 kg of honey at 1,420 kg/m3 is 1.76056 L.
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Frequently asked questions
Are grams and millilitres the same?
Only for water near 4 degrees Celsius, where the density is close to 1,000 kg/m3. For other substances the mass of one millilitre is the density in grams per millilitre, so milk is 1.03 g per mL and honey about 1.42 g per mL.
How many grams are in a litre of water?
About 1,000 g, which is one kilogram. Water is most dense near 4 degrees Celsius at almost 1,000 kg/m3, and warm water is slightly lighter.
Why does this page ask for a substance?
A litre measures volume and a gram measures mass, so the answer depends on how dense the substance is. Without a density there is no single correct number of grams.
Can I use this for a recipe?
Yes, for liquids and for pourable ingredients with a known density. Dry flour and sugar pack differently depending on how they are scooped, so a kitchen scale is still more reliable than a volume conversion for baking.