Convert mL to mg using the substance's density. Water: 1 mL = 1,000 mg. Presets for milk, honey, olive oil, alcohol, glycerin and syrup, plus a custom density option.
Milligrams = mL × density (g/mL) × 1,000. Water at room temperature is close enough to 1.000 g/mL for everyday use, so 1 mL of water ≈ 1,000 mg.
| mL | mg (water) | mg (honey) | mg (olive oil) |
|---|---|---|---|
| 1 mL | 1,000 mg | 1,420 mg | 916 mg |
| 2.5 mL | 2,500 mg | 3,550 mg | 2,290 mg |
| 5 mL | 5,000 mg | 7,100 mg | 4,580 mg |
| 10 mL | 10,000 mg | 14,200 mg | 9,160 mg |
| 15 mL | 15,000 mg | 21,300 mg | 13,740 mg |
| 30 mL | 30,000 mg | 42,600 mg | 27,480 mg |
| 100 mL | 100,000 mg | 142,000 mg | 91,600 mg |
For water, 1 mL = 1,000 mg, because water has a density of about 1 g/mL. For any other liquid the answer changes with density: 1 mL of honey is about 1,420 mg, while 1 mL of olive oil is about 916 mg.
mL measures volume and mg measures mass. The bridge between them is density (mass per volume). Two liquids with the same volume can have very different masses, a cup of mercury weighs over 13 times a cup of water.
Liquid medicines are labeled with a concentration such as 100 mg per 5 mL (20 mg/mL). Use the concentration printed on the label, not a generic density, and follow the dosing instructions from the label or your doctor.
Only for water and liquids with a density very close to 1 g/mL (milk at 1.03 is close). Oils are lighter, syrups and honey are heavier, and alcohol is noticeably lighter at 0.789 g/mL.