Units to mg calculator
Convert between compound amount and liquid volume using a concentration you supply. The syringe scale here is U-100: 1 mL equals 100 units. A unit marking alone cannot tell you the amount in mg because that amount changes with the concentration of the liquid.
Units to mg reference table
| U-100 units | 2.5 mg/mL | 5 mg/mL | 10 mg/mL | 15 mg/mL | 20 mg/mL |
|---|---|---|---|---|---|
| 10 | 0.25 mg | 0.5 mg | 1 mg | 1.5 mg | 2 mg |
| 20 | 0.5 mg | 1 mg | 2 mg | 3 mg | 4 mg |
| 25 | 0.625 mg | 1.25 mg | 2.5 mg | 3.75 mg | 5 mg |
| 30 | 0.75 mg | 1.5 mg | 3 mg | 4.5 mg | 6 mg |
| 40 | 1 mg | 2 mg | 4 mg | 6 mg | 8 mg |
| 50 | 1.25 mg | 2.5 mg | 5 mg | 7.5 mg | 10 mg |
How the conversion works
Divide syringe units by 100 to get milliliters, then multiply that volume by concentration to get milligrams. To move in the other direction, divide milligrams by concentration before multiplying by 100. Keep the concentration in mg per mL throughout a calculation so the amount and volume units cancel consistently.
mg = units ÷ 100 × concentration mg/mL
mL = mg ÷ concentration mg/mL
units = mL × 100
The vial mode divides vial contents in mg by the entered water volume in mL. That mode assumes the water volume equals the final solution volume. An already mixed solution can instead use its labeled concentration directly. An IU amount cannot be entered as mg; HCG's IU chart keeps its compound unit separate from the volume scale.
Tirzepatide and semaglutide arithmetic examples
For a tirzepatide example, 10 mg divided by 2 mL gives 5 mg per mL. At that concentration, 20 units is 0.2 mL and contains 1 mg. A 2.5 mg amount occupies 0.5 mL, which corresponds to 50 units. These numbers describe one concentration assumption and do not select an amount.
For a semaglutide example using the same 10 mg and 2 mL values, 0.5 mg divided by 5 mg per mL gives 0.1 mL, or 10 units. The compound name does not change the formula. Changing either vial contents or final volume does change the concentration, so an old unit marking cannot establish a new amount.
Fractional outputs describe mathematical volume, not the measurement precision of a device. A volume above 1 mL is flagged as over one syringe on the stated scale. The converter does not split that amount into injections or choose equipment, timing, or preparation instructions. Positive finite values are required for every active input.
Questions about the conversion
How many mg is 20 units?
It depends on concentration. On a U-100 syringe, 20 units is 0.2 mL. At 2.5 mg per mL it contains 0.5 mg; at 5 mg per mL it contains 1 mg; at 10 mg per mL it contains 2 mg.
How many mg is 50 units?
50 U-100 units equals 0.5 mL. Multiply 0.5 by concentration in mg per mL: at 5 mg per mL the amount is 2.5 mg, and at 20 mg per mL it is 10 mg.
How many units is 1 mg?
At 5 mg per mL, 1 mg occupies 0.2 mL, or 20 U-100 units. At 10 mg per mL, 1 mg occupies 0.1 mL, or 10 units. Concentration is required for this conversion.
Can a vial amount determine mg per unit on its own?
No. A 10 mg vial in a final volume of 2 mL gives 5 mg per mL and 0.05 mg per U-100 unit. The same amount in 1 mL gives 10 mg per mL and 0.1 mg per unit.
Track your calculations in the app
PinPoint for iOS brings vial setup, unit conversion, dose logs, site rotation, and protocol tracking together. Enter vial size and water volume for concentration and syringe units, then log injections with compound, dose, site, and pain level.
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