Why you can't convert grams to milliliters with one universal number
Grams measure mass. Milliliters measure volume. The reason "1 mL = 1 g" works as a rough shortcut for water is that water has a density close to 1 g/mL. It does not apply to most other kitchen ingredients. Using the reference densities in this converter, 100 mL of honey is about 142 g, while 100 mL of all-purpose flour is about 53 g. The conversion factor between mass and volume is density, measured here in grams per milliliter (g/mL).
Where these density figures come from, and their real limits
The values built into this converter are standard kitchen reference densities, cross-checked against independent culinary sources rather than pulled from a single chart:
| Ingredient | Density | Mass of 100 mL |
|---|---|---|
| Water | 1.00 g/mL | 100 g |
| Milk | 1.03 g/mL | 103 g |
| Flour, all-purpose | 0.53 g/mL | 53 g |
| Sugar, granulated | 0.85 g/mL | 85 g |
| Honey | 1.42 g/mL | 142 g |
| Vegetable oil | 0.92 g/mL | 92 g |
| Butter, melted | 0.96 g/mL | 96 g |
These are useful reference values rather than guarantees for every brand, batch, or measuring technique. Dry ingredients such as flour can vary substantially in mass for the same measured volume because scooping, spooning, sifting, and settling change how much material is packed into the measuring vessel. Temperature can also affect the volume and density of liquids. For baking where consistency matters, weighing ingredients directly is generally more reproducible than converting from volume.
What can change an ingredient's density?
While standard density tables give a reliable baseline, physical kitchen conditions introduce variable margins:
- Aeration and compaction: Dry ingredients such as flour can have different weights for the same volume depending on how tightly they are packed.
- Temperature: Liquids such as oils and honey expand and contract with temperature, slightly changing their density.
- Moisture: Ingredients that absorb moisture can change in mass and therefore in their effective density.
Worked examples: oil and milk
If you're wondering how many grams are in 100 mL of oil or milk, the answer depends on density. Vegetable oil at 0.92 g/mL weighs about 92 g per 100 mL, while milk at 1.03 g/mL weighs about 103 g per 100 mL.
These two are common examples, and they fail the common assumption in opposite directions. The habit of treating 1 mL as 1 g comes from water, whose density is close to 1 g/mL under typical kitchen conditions. It is not a universal rule for other ingredients.
grams = millilitres × densitymillilitres = grams ÷ density Oil — multiply by 0.92
| Volume | Working | Weight |
|---|---|---|
| 1 tsp (5 mL) | 5 × 0.92 | 4.6 g |
| 1 tbsp (15 mL) | 15 × 0.92 | 13.8 g |
| 60 mL | 60 × 0.92 | 55.2 g |
| 100 mL | 100 × 0.92 | 92 g |
| 250 mL | 250 × 0.92 | 230 g |
| 500 mL | 500 × 0.92 | 460 g |
Going the other way, divide: a recipe asking for 200 g of oil needs 200 ÷ 0.92 = 217 mL. Pouring 200 mL instead would leave you 16 g short — a little more than one tablespoon of oil.
Milk — multiply by 1.03
| Volume | Working | Weight |
|---|---|---|
| 1 tbsp (15 mL) | 15 × 1.03 | 15.45 g |
| 100 mL | 100 × 1.03 | 103 g |
| 240 mL (1 US cup) | 240 × 1.03 | 247.2 g |
| 250 mL | 250 × 1.03 | 257.5 g |
| 500 mL | 500 × 1.03 | 515 g |
| 1 L | 1000 × 1.03 | 1030 g |
And in reverse: 300 g of milk is 300 ÷ 1.03 = 291 mL.
Is there a single standard ratio?
Not one that covers both. The conversion factor is the ingredient's density, which is a property of the ingredient rather than a convention anyone chose. What does exist are useful reference densities for individual ingredients.
Common vegetable oils have slightly different densities, so 0.92 g/mL is not exact for every oil. It is a practical generic reference for everyday cooking; if the specific oil matters, enter its density using the custom-density option.
Does milk fat change the density?
Yes, slightly. Milk density varies with fat content and other composition factors, so whole, semi-skimmed, and skimmed milk do not have exactly the same density. For everyday cooking, however, the differences are small enough that 1.03 g/mL is a useful general reference value.
A note on units & international recipe scaling
Milliliters (mL) and liters (L) are metric volume units, so their definitions are consistent internationally. Recipe cups and tablespoons, however, can differ between measurement systems.
For US customary recipes, use our Cups to mL Converter or mL to Cups Converter when converting between cups and metric volume. For tablespoon-based recipes, see our Tablespoons to Cups Converter and Cups to Tablespoons Converter.
Need to convert fluid ounces rather than cups? Use our Oz to mL Converter for US Customary and Imperial fluid-ounce conversions.
Frequently asked questions
What is the standard ratio for converting oil and milk from mL to grams?
There is no single ratio covering both — the ratio is the ingredient's density. As useful kitchen reference values, multiply millilitres by 0.92 for vegetable oil and by 1.03 for milk. So 100 mL of oil is about 92 g and 100 mL of milk is about 103 g. Water is close to 1 g/mL, so it is often treated as a 1:1 conversion in kitchen recipes.
How many grams is 100 mL of flour?
About 53 g, using a standard all-purpose flour density of 0.53 g/mL. This varies by how the flour is measured — sifted flour weighs noticeably less than packed flour for the same volume.
How many grams is 100 mL of honey?
About 142 g, since honey is considerably denser than water at roughly 1.42 g/mL.
Can I convert an ingredient that isn't in the list?
Yes — choose "Custom Density" and enter the ingredient's known density in g/mL. If you know that a specific weight fills a specific volume (say, 62 g fills 50 mL), divide weight by volume to get the density (1.24 g/mL in that example).
Why do professional bakers prefer grams over milliliters?
Measuring ingredients by mass makes quantities more reproducible because it avoids many of the variation introduced by air pockets, packing, and uneven volume measurements. This is especially useful when a recipe depends on consistent ingredient ratios.