Published by Peptide Protocols · Reviewed September 2026 · How we make these pages · Educational & research purposes only — not medical advice.
1 mL = 100 units on a U-100 insulin syringe. Formula: mg ÷ mL = mg/mL; (mcg ÷ 1000) ÷ mg/mL = mL; mL × 100 = units.
Units to draw on a U-100 insulin syringe for the common vial sizes and water volumes. Pick the row that matches your vial and the water you added.
| Vial + water | Concentration | 2.5 mg | 5 mg | 7.5 mg | 10 mg | 12.5 mg | 15 mg |
|---|---|---|---|---|---|---|---|
| 5 mg vial + 1 mL water | 5 mg/mL | 50 u | 100 u | 150 u | 200 u | 250 u | 300 u |
| 5 mg vial + 2 mL water | 2.5 mg/mL | 100 u | 200 u | 300 u | 400 u | 500 u | 600 u |
| 5 mg vial + 3 mL water | 1.66667 mg/mL | 150 u | 300 u | 450 u | 600 u | 750 u | 900 u |
| 10 mg vial + 1 mL water | 10 mg/mL | 25 u | 50 u | 75 u | 100 u | 125 u | 150 u |
| 10 mg vial + 2 mL water | 5 mg/mL | 50 u | 100 u | 150 u | 200 u | 250 u | 300 u |
| 10 mg vial + 3 mL water | 3.33333 mg/mL | 75 u | 150 u | 225 u | 300 u | 375 u | 450 u |
| 15 mg vial + 1 mL water | 15 mg/mL | 17 u | 33 u | 50 u | 67 u | 83 u | 100 u |
| 15 mg vial + 2 mL water | 7.5 mg/mL | 33 u | 67 u | 100 u | 133 u | 167 u | 200 u |
| 15 mg vial + 3 mL water | 5 mg/mL | 50 u | 100 u | 150 u | 200 u | 250 u | 300 u |
| 20 mg vial + 1 mL water | 20 mg/mL | 12 u | 25 u | 38 u | 50 u | 62 u | 75 u |
| 20 mg vial + 2 mL water | 10 mg/mL | 25 u | 50 u | 75 u | 100 u | 125 u | 150 u |
| 20 mg vial + 3 mL water | 6.66667 mg/mL | 38 u | 75 u | 112 u | 150 u | 188 u | 225 u |
| 30 mg vial + 1 mL water | 30 mg/mL | 8 u | 17 u | 25 u | 33 u | 42 u | 50 u |
| 30 mg vial + 2 mL water | 15 mg/mL | 17 u | 33 u | 50 u | 67 u | 83 u | 100 u |
| 30 mg vial + 3 mL water | 10 mg/mL | 25 u | 50 u | 75 u | 100 u | 125 u | 150 u |
Worked example: a 10 mg vial with 2 mL of bacteriostatic water is 5 mg/mL. A 2.5 mg draw is 0.50 mL, which is 50 units. Change the water and every number on the syringe changes — which is the single most common reconstitution mistake. The full explanation is in How to Reconstitute Peptides.
2 mL gives 5 mg/mL, so 2.5 mg = 0.5 mL = 50 units and 5 mg = 100 units (a full U-100 syringe). 1 mL gives 10 mg/mL, so 2.5 mg = 25 units. The chart below covers 5 mg to 30 mg vials.
mg ÷ (mg/mL) = mL; mL × 100 = units on a U-100 insulin syringe. A 7.5 mg draw from a 10 mg/mL solution is 0.75 mL = 75 units.
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