mg to mL calculator
Updated 24 October 2026
To turn milligrams into millilitres you need the concentration of the liquid: how many mg are in each mL. It is printed on the vial or bottle label, as "5 mg/mL" or as a total such as "10 mg/2 mL". There is no fixed mg-to-mL ratio for medicines, because every product has its own concentration.
Calculator
Draw 20 units (0.2 mL)
1 mg at 5 mg/mL on a U-100, 1 mL (100 units) syringe. Round to the nearest mark your syringe has.
Draw to 20 units
U-100, 1 mL (100 units) insulin syringe
Free, no account needed. Your vials stay on this device.
The formula
mL = dose (mg) ÷ concentration (mg/mL)
- 1 mg at 5 mg/mL: 1 ÷ 5 = 0.2 mL
- 2.5 mg at 10 mg/mL: 2.5 ÷ 10 = 0.25 mL
- 0.25 mg at 2.5 mg/mL: 0.25 ÷ 2.5 = 0.1 mL
If the label gives a total, divide it first: "10 mg/2 mL" is 10 ÷ 2 = 5 mg/mL. On a U-100 insulin syringe, multiply mL by 100 to get units: 0.2 mL is 20 units.
mg to mL chart
| Dose | 1 mg/mL | 2.5 mg/mL | 5 mg/mL | 10 mg/mL | 20 mg/mL |
|---|---|---|---|---|---|
| 0.25 mg | 0.25 mL | 0.1 mL | 0.05 mL | 0.025 mL | 0.013 mL |
| 0.5 mg | 0.5 mL | 0.2 mL | 0.1 mL | 0.05 mL | 0.025 mL |
| 1 mg | 1 mL | 0.4 mL | 0.2 mL | 0.1 mL | 0.05 mL |
| 2.5 mg | 2.5 mL | 1 mL | 0.5 mL | 0.25 mL | 0.125 mL |
| 5 mg | 5 mL | 2 mL | 1 mL | 0.5 mL | 0.25 mL |
| 10 mg | 10 mL | 4 mL | 2 mL | 1 mL | 0.5 mL |
mg, mcg and mL
mg and mcg are both amounts of drug: 1 mg is 1,000 mcg. mL is volume. Convert mcg to mg before using the formula, or the answer comes out 1,000 times too big.