mL to kg Converter
Milliliters measure volume; kilograms measure mass. To move between them you need the density of the substance. Pick a common substance from the list and the density fills in automatically, or choose Custom and enter your own density. The result updates instantly in both directions: enter volume to get mass, or enter mass to get volume.
Why you need density to convert mL to kg
Milliliters and kilograms measure different physical properties: milliliters count volume (how much space something occupies) while kilograms count mass (how much matter it contains). A milliliter of honey weighs about 1.42 g, while a milliliter of olive oil weighs only about 0.91 g. That difference is density. The formula is: mass (g) = volume (mL) x density (g/mL), then divide by 1,000 to reach kilograms. Without knowing what substance you are measuring, the conversion is impossible. For water at room temperature the density is almost exactly 1.000 g/mL, which is why 1,000 mL (one liter) of water weighs almost exactly 1 kg.
The formula explained
The conversion works in two steps. First, find the mass in grams: mass (g) = volume (mL) x density (g/mL). Second, convert grams to kilograms: mass (kg) = mass (g) / 1,000. Combining those steps gives the single formula: kg = (mL x density) / 1,000. For the reverse direction, rearrange to: mL = (kg x 1,000) / density. For example, 250 mL of whole milk (density 1.030 g/mL) weighs 250 x 1.030 / 1,000 = 0.2575 kg (257.5 g).
How density changes with temperature
Density is not perfectly constant. Water reaches its maximum density of 1.000 g/mL at 4 degrees Celsius and is slightly less dense at room temperature (0.998 g/mL at 20 C). Oils thin out more noticeably with heat. For everyday cooking and baking the standard room-temperature values used in this calculator are accurate enough. For laboratory or industrial work where precision matters, consult a certified density table at the exact process temperature.
Practical uses for the mL-to-kg conversion
Bakers use the conversion to weigh liquids on a kitchen scale instead of chasing measuring cups, reducing cleanup and improving accuracy. Chemists convert volumetric measurements in graduated cylinders to mass for reaction calculations. Nutritionists and food scientists calculate the mass of a measured portion. Freight and shipping teams convert liquid cargo volume to shipment weight for customs and loading declarations. Medical professionals calculate medication masses from prescribed volumes, particularly for compounding pharmacists and IV preparations.
Density of common substances (g/mL at 20 C)
| Substance | Density (g/mL) | 100 mL = ? kg | 1 kg = ? mL |
|---|---|---|---|
| Water | 1 | 0.1000 | 1000.0 |
| Whole milk | 1.03 | 0.1030 | 970.9 |
| Heavy cream | 1.006 | 0.1006 | 994.0 |
| Honey | 1.42 | 0.1420 | 704.2 |
| Olive oil | 0.91 | 0.0910 | 1098.9 |
| Vegetable oil | 0.92 | 0.0920 | 1087.0 |
| Butter / ghee | 0.911 | 0.0911 | 1097.7 |
| Flour, all-purpose | 0.529 | 0.0529 | 1890.4 |
| Sugar, white | 0.845 | 0.0845 | 1183.4 |
| Table salt | 1.217 | 0.1217 | 821.7 |
| Ethanol | 0.789 | 0.0789 | 1267.4 |
| Seawater | 1.025 | 0.1025 | 975.6 |
| Mercury | 13.534 | 1.3534 | 73.9 |
Multiply the volume in mL by the density, then divide by 1,000 to get kilograms.
Frequently asked questions
How many kg is 1 mL?
It depends entirely on the substance. 1 mL of water weighs 0.001 kg (1 g). 1 mL of honey weighs about 0.00142 kg (1.42 g). 1 mL of olive oil weighs about 0.00091 kg (0.91 g). The formula is: kg = mL x density / 1,000.
How many mL is 1 kg?
Again, it depends on density. 1 kg of water is exactly 1,000 mL (1 liter). 1 kg of honey is about 704 mL. 1 kg of olive oil is about 1,099 mL. The formula is: mL = kg x 1,000 / density.
Is 1 mL of water equal to 1 g?
Very nearly. At 4 degrees Celsius water has a density of exactly 1.000 g/mL, so 1 mL = 1 g exactly. At 20 degrees Celsius (room temperature) the density is 0.9982 g/mL, so 1 mL is 0.9982 g. For all practical cooking and baking purposes the difference is negligible and you can treat 1 mL of water as 1 g.
Why does my kitchen scale give a different weight than the mL measurement?
Because your scale measures mass (grams or kilograms) and your measuring cup measures volume (milliliters). They agree only for water. For liquids denser than water, like honey or milk, you get more grams per milliliter than you would expect. For liquids lighter than water, like vegetable oil, you get fewer grams. Always use the density of your specific ingredient to reconcile the two.
How do I convert mL to kg for flour or sugar?
Use the density of the ingredient. All-purpose flour has a density of about 0.529 g/mL when scooped loosely, so 500 mL of flour weighs about 500 x 0.529 / 1,000 = 0.265 kg (265 g). White granulated sugar has a density of about 0.845 g/mL, so 500 mL of sugar weighs about 500 x 0.845 / 1,000 = 0.423 kg (423 g). Packed or sifted flour will have a different density, so these are good approximations for typical preparation.
Can I use this converter for any liquid?
Yes. Choose Custom substance from the dropdown and enter the density of your liquid in g/mL. Density values are widely available in chemistry handbooks, material safety data sheets, and the NIST WebBook for pure substances.