mg to units calculator
Milligrams are mass. Units are volume. Converting between them needs one more number, your concentration, and that is what most answers to this question leave out.
Why "how many units is 1 mg" has no answer on its own. A unit is 0.01 mL of liquid. How much peptide is dissolved in that 0.01 mL depends on how much water you added. The same 1 mg is 20 units in one vial and 10 units in another. Fill in all three boxes below and the answer is exact.
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ReviewedDose ranges and half-life figures last checked 29 August 2026.
The formula
concentration (mg/mL) = mg in the vial / mL of bacteriostatic water
units on a U-100 syringe = (dose in mg / concentration) x 100
Going the other way, which the second tab above does for you: dose in mg = (units / 100) x concentration.
The same dose at different concentrations
| Vial | BAC water | Concentration | Draw | U-100 units | Doses/vial |
|---|---|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | 0.2 mL | 20 units | 5 |
| 5 mg | 2 mL | 2.5 mg/mL | 0.4 mL | 40 units | 5 |
| 5 mg | 3 mL | 1.67 mg/mL | 0.6 mL | 60 units | 5 |
| 10 mg | 1 mL | 10 mg/mL | 0.1 mL | 10 units | 10 |
| 10 mg | 2 mL | 5 mg/mL | 0.2 mL | 20 units | 10 |
| 10 mg | 3 mL | 3.33 mg/mL | 0.3 mL | 30 units | 10 |
| 20 mg | 1 mL | 20 mg/mL | 0.05 mL | 5 units | 20 |
| 20 mg | 2 mL | 10 mg/mL | 0.1 mL | 10 units | 20 |
| 20 mg | 3 mL | 6.67 mg/mL | 0.15 mL | 15 units | 20 |
| 30 mg | 1 mL | 30 mg/mL | 0.033 mL | 3.3 units | 30 |
| 30 mg | 2 mL | 15 mg/mL | 0.067 mL | 6.7 units | 30 |
| 30 mg | 3 mL | 10 mg/mL | 0.1 mL | 10 units | 30 |
All rows above assume a 1 mg dose and a standard U-100 insulin syringe, where 100 units = 1 mL.
Free: The Protocol Pack, 25 printable pages. Including the part no other site writes down: what to do when you have already got it wrong. Wrong water volume, shook the vial, left it out overnight, drew the wrong units. Plus dosing cards for twelve compounds, titration planners and a vial log. Get it free.
Calculators by compound
RetatrutideVial, water and weekly dose to syringe unitsTirzepatideThe 2.5 to 15 mg ladder, convertedSemaglutideThe 0.25 to 2.4 mg ladder, convertedBPC-157mcg doses from a 5 or 10 mg vialReconstitutionHow much water to add, and why it mattersDosing chartsPrintable unit tables for every compoundTitration schedulesFull ladders with units at every stepReading a syringeU-100 vs U-40, and the 2.5x errorHow much water?Pick a volume that lands where you can read it
Common questions
- How many units is 1 mg?
- There is no single answer. Units measure volume, milligrams measure mass, and the link between them is the concentration of your vial. 1 mg of a 5 mg/mL solution is 20 units. 1 mg of a 10 mg/mL solution is 10 units.
- What is the formula for mg to units?
- units = (dose in mg / concentration in mg per mL) x 100, on a U-100 syringe. Concentration is the mg in your vial divided by the mL of bacteriostatic water you added.
- How many units is 2.5 mg of tirzepatide?
- In a 30 mg vial with 3 mL of water, which is 10 mg/mL, 2.5 mg is 0.25 mL, or 25 units. In a 10 mg vial with 2 mL, which is 5 mg/mL, the same 2.5 mg is 50 units.
- How do I convert mcg to units?
- Divide by 1000 to get milligrams first, then use the same formula. 250 mcg is 0.25 mg.
Read this before you use the numbers. This is a unit-conversion tool. It converts a vial strength and a volume of bacteriostatic water into a concentration, a draw volume and a mark on an insulin syringe. It does not tell you what to take, whether to take it, or whether a compound is safe for you. Most of the compounds listed here are sold for laboratory research use and are not approved for human use. Nothing on this site is medical advice. Dosing decisions belong with a licensed clinician who knows your history. Always confirm the strength printed on your own vial rather than trusting a preset.