Grams to Milliliters for Cooking: Why They Are Not Always Equal
Published 6/8/2026 · 3 min read · Everyday calculators
Grams measure weight and milliliters measure volume, so you can only convert between them if you know the ingredient's density. For water, the two match exactly: 1 gram equals 1 milliliter. But most kitchen ingredients differ. Flour is light, so about 1 gram takes up nearly 2 mL; granulated sugar is denser, near 1 gram per 1.2 mL; oil is lighter than water, so 1 gram is about 1.1 mL. To convert, divide grams by density in grams per mL, or use a converter that stores each ingredient's density.
Grams measure weight and milliliters measure volume, so converting between them depends on density. Water is 1 gram per mL, but flour, sugar, and oil are not. Here is how to convert correctly.
Weight versus volume
A gram is a unit of mass — how heavy something is. A milliliter is a unit of volume — how much space it takes up. The two are only interchangeable when a substance has a density of exactly 1 gram per milliliter. Water is that reference: at room temperature, 1 mL of water weighs almost exactly 1 gram, which is why recipes can use them interchangeably for water.
This is why a kitchen scale and a measuring cup can disagree. Weighing is more accurate because it ignores how tightly an ingredient is packed. A cup of flour scooped straight from the bag can weigh far more than a cup spooned in loosely, but 120 grams of flour is always 120 grams. When precision matters, weigh in grams.
Density of common ingredients
Water sets the baseline at 1 gram per mL, so 250 grams of water is 250 mL. Milk is close, about 1.03, so grams and mL are nearly the same. All-purpose flour is light and airy, roughly 0.53 grams per mL, meaning 100 grams occupies about 190 mL. Granulated sugar is heavier at about 0.85 grams per mL, so 100 grams is around 118 mL.
Oils and fats float on water because they are less dense — around 0.92 grams per mL — so 100 grams of oil is about 109 mL. Honey and syrups go the other way, denser than water at roughly 1.42 grams per mL, so 100 grams is only about 70 mL. Because each ingredient behaves differently, a single gram-to-mL rule does not exist; you need the right density for each.
How to convert correctly
The formula is simple once you have the density. Milliliters equal grams divided by density in grams per mL. For 200 grams of flour at 0.53 g/mL, that is 200 divided by 0.53, about 377 mL. Going the other way, grams equal milliliters times density: 250 mL of oil at 0.92 g/mL weighs about 230 grams.
In practice, most home cooks do not want to look up densities mid-recipe. A cooking converter stores the density of flour, sugar, butter, milk, oil, honey, and dozens more, so you pick the ingredient and it does the math. That avoids the classic mistake of treating grams and milliliters as equal for everything but water.
Frequently asked questions
- Is 1 gram always equal to 1 milliliter?
- Only for water and near-water liquids. For flour, sugar, oil, or honey the density differs, so grams and mL are not equal.
- How many mL is 100 grams of flour?
- About 190 mL, because all-purpose flour has a density near 0.53 grams per mL.
- Why is weighing more accurate than a measuring cup?
- Weight ignores how tightly an ingredient is packed. A cup of flour can vary a lot in grams, but 120 grams is always 120 grams.
- How do I convert grams to mL for an ingredient?
- Divide the grams by the ingredient's density in grams per mL, or use a cooking converter that stores each density for you.
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