Insulin Syringe Units to mg Calculator
Work backwards from the line on a U-100 insulin syringe to the dose in mg or mcg, for any vial strength.
Updated · By Niraj Kumar · 3 sources
https://checkpre.com/health/insulin-syringe-units-to-mg-calculator
Medication
Vial strength
Printed on the vial label, e.g. "2.5 mg/mL". Common semaglutide strengths: 1, 2.5, 5 mg/mL.
Your syringe
The number on the line the plunger's front edge sits at, on a U-100 insulin syringe.
- Volume
- 0.1 mL
- 1 unit = 0.01 mL on a U-100 syringe
- Formula
- 10 ÷ 100 × 2.5
- Units ÷ 100 × concentration = dose in mg
| Weekly dose | When | Units | mL |
|---|---|---|---|
| 0.25 mg | Weeks 1–4 | 10 units | 0.1 mL |
| 0.5 mg | Weeks 5–8 | 20 units | 0.2 mL |
| 1 mg | Weeks 9–12 | 40 units (over capacity) | 0.4 mL |
| 1.7 mg | Weeks 13–16 | 68 units (over capacity) | 0.68 mL |
| 2.4 mg | Week 17 on (usual maintenance) | 96 units (over capacity) | 0.96 mL |
| 7.2 mg | Only if prescribed after 4+ weeks at 2.4 mg | 288 units (over capacity) | 2.88 mL |
How do you convert syringe units to mg?
Divide the units by 100 to get mL, then multiply by the vial's concentration in mg/mL. 20 units from a 2.5 mg/mL vial is 0.2 mL × 2.5 = 0.5 mg. The same 20 units from a 10 mg/mL vial is 2 mg, so the units alone never tell you the dose.
units = dose (mg) ÷ concentration (mg/mL) × 100This page uses the same method as the GLP-1 Dosage Calculator, which explains each term and assumption in full.
| Units drawn | At 2.5 mg/mL | At 5 mg/mL | At 10 mg/mL |
|---|---|---|---|
| 5 units (0.05 mL) | 0.125 mg | 0.25 mg | 0.5 mg |
| 10 units (0.1 mL) | 0.25 mg | 0.5 mg | 1 mg |
| 20 units (0.2 mL) | 0.5 mg | 1 mg | 2 mg |
| 25 units (0.25 mL) | 0.625 mg | 1.25 mg | 2.5 mg |
| 30 units (0.3 mL) | 0.75 mg | 1.5 mg | 3 mg |
| 40 units (0.4 mL) | 1 mg | 2 mg | 4 mg |
| 50 units (0.5 mL) | 1.25 mg | 2.5 mg | 5 mg |
| 75 units (0.75 mL) | 1.875 mg | 3.75 mg | 7.5 mg |
| 100 units (1 mL) | 2.5 mg | 5 mg | 10 mg |
Worked example
20 units drawn from a vial labelled 2.5 mg/mL.
- 1Volume: 20 units ÷ 100 = 0.2 mL
- 2Dose: 0.2 mL × 2.5 mg/mL = 0.5 mg
20 units holds 0.5 mg (500 mcg).
Frequently asked questions
How many mg is 10 units?
10 units is 0.1 mL on a U-100 syringe. That is 0.25 mg at 2.5 mg/mL, 0.5 mg at 5 mg/mL and 1 mg at 10 mg/mL. Multiply 0.1 by your vial's mg/mL for your figure.
How many mL is one unit?
On a U-100 insulin syringe, 1 unit is 0.01 mL and 100 units is 1 mL. A 0.3 mL syringe holds 30 units and a 0.5 mL syringe holds 50 units.
Sources
Related calculators
- GLP-1 Dosage CalculatorTurn a prescribed semaglutide or tirzepatide dose in mg into the exact line on a U-100 insulin syringe, with the syringe drawn to scale.
- Semaglutide Dosage CalculatorCompounded semaglutide in mg to units on an insulin syringe, for any vial strength, with the Wegovy titration converted for your vial.
- Tirzepatide Dosage CalculatorCompounded or vial tirzepatide in mg to units on an insulin syringe, with the Zepbound 2.5 to 15 mg titration converted for your vial.
- Peptide Reconstitution CalculatorMix a peptide vial with bacteriostatic water and find the units to draw for a dose in mcg or mg on a U-100 insulin syringe.