You cannot go from mL to pounds without a density
Millilitres measure volume and pounds measure weight, so the bridge between them is density — how heavy the liquid is for its size. Set the density (water is the default) and the math is one multiply and one divide.
The 453.592 is fixed: one avoirdupois pound is exactly 453.592 grams. So for water, where density is 1, it takes 453.592 mL to make one pound.
Weight of 100 mL and 500 mL, by liquid
| Substance | Density (g/mL) | 100 mL | 500 mL |
|---|---|---|---|
| Water | 1.00 | 0.220 lb | 1.10 lb |
| Milk | 1.03 | 0.227 lb | 1.14 lb |
| Olive oil | 0.92 | 0.203 lb | 1.01 lb |
| Ethanol (alcohol) | 0.79 | 0.174 lb | 0.87 lb |
| Honey | 1.42 | 0.313 lb | 1.57 lb |
| Table salt | 2.17 | 0.478 lb | 2.39 lb |
| Mercury | 13.55 | 2.99 lb | 14.94 lb |
If your substance is not listed, type its density into the calculator. Flour is about 0.57 g/mL and granulated sugar about 0.85 g/mL, so neither behaves like water.
Getting the density right
- Temperature nudges it. Water is 1.000 g/mL at 4°C but 0.998 g/mL at 20°C. For kitchen and everyday work, treating water as 1.0 is close enough.
- Use avoirdupois, not troy. This uses the everyday pound of 453.592 g. The troy pound (373.24 g) is only for precious metals and would throw the answer off.
- Round at the end. Keep full precision through the multiply and divide, then round the final pounds — rounding the density first can drift the result.
Common questions
How do I convert mL to pounds?
You need the density. Multiply the millilitres by the density in grams per mL to get grams, then divide by 453.592 to get pounds. For water, density is 1, so 453.592 mL of water weighs 1 pound.
How much does 500 mL weigh in pounds?
It depends on the liquid. 500 mL of water is about 1.10 lb; 500 mL of olive oil is about 1.01 lb; 500 mL of honey is about 1.57 lb. Same volume, different weight, because density differs.
Is 1 mL always 1 gram?
Only for water, and only close to it. Oil is lighter (about 0.91 g/mL) and honey is heavier (about 1.42 g/mL), so assuming 1 mL equals 1 gram will be wrong for anything but water.
