Unit conversion
How to convert cooking units: grams, cups, and ounces
Learn how to convert cooking measurements between grams, cups, ounces, and milliliters, and why density changes the math.
Document summary
A guide to converting cooking measurements: grams, cups, ounces, and milliliters, with the density caveats that matter in recipes.
Key takeaways
- Weight units convert exactly; volume and weight do not
- A cup of flour weighs far less than a cup of sugar
- Convert with the tool, then verify against the recipe
Weight versus volume
Grams, kilograms, and ounces measure weight. Cups, tablespoons, and milliliters measure volume. They convert cleanly only for water-like liquids, where 1 milliliter weighs about 1 gram.
For flour, sugar, butter, and other ingredients, the same cup holds a different weight. Recipe writers who use weight are more consistent for this reason.
Conversions that come up constantly
- 1 cup = 240 milliliters (and about 240 g of water)
- 1 tablespoon = 15 milliliters
- 1 ounce (weight) = about 28.35 grams
- 1 fluid ounce = about 29.6 milliliters
- 1 pound = 453.6 grams
Convert with the tools
- 1
For weight conversions such as pounds to grams, open the weight converter.
- 2
For volume such as cups to milliliters, use the volume converter.
- 3
Type the value and read the converted result and table.
- 4
When the recipe says cups but you measure by weight, check an ingredient density table before converting.
Scaling recipes
When doubling or halving a recipe, convert each ingredient with the same tool pass and round sensibly: fractions such as 1/3 cup are easier to measure than 79.5 milliliters.
Frequently asked questions
Why does 1 cup of flour not equal 1 cup of sugar in grams?
Cups measure volume. Flour is much less dense than sugar, so the same cup holds a different weight of each.
Is 1 milliliter always 1 gram?
Only for water and liquids of similar density. Oil, honey, and syrups differ.
Which unit is best for baking?
Weight (grams or ounces) is the most reproducible for baking because it removes the density problem.
Are my values uploaded?
No. Conversions run locally in your browser.
