How many units is 1 mg on an insulin syringe?

It depends on the concentration. At 5 mg/mL (for example a 10 mg vial in 2 mL) 1 mg is 0.2 mL, which is 20 units on a U-100 syringe. At 10 mg/mL it is 10 units. At 2.5 mg/mL it is 40 units.

How many units is 0.5 mg?

Half of whatever 1 mg is at your concentration. At 5 mg/mL, 10 units. At 2.5 mg/mL, 20 units.

How many units is 1 mL?

On a U-100 insulin syringe, 100 units. On a U-40 syringe, 40 units. Units measure volume; check which scale is printed on your barrel.

How many mcg is 10 units?

Multiply the concentration in mcg/mL by 0.1. At 2,500 mcg/mL (5 mg in 2 mL), 10 units is 250 mcg.

1 mg to units on an insulin syringe

It depends on the concentration, and this page gives the number for every common one. 1 mg is 20 units at 5 mg/mL, 10 units at 10 mg/mL, 40 units at 2.5 mg/mL.

The short answer

There is no fixed number of units in 1 mg. A unit on an insulin syringe is a volume (0.01 mL on a U-100 syringe), and a milligram is a mass. How many units 1 mg takes depends on how concentrated the solution is, which you set when you add water. The table gives the answer for every common concentration.

1 mg in units, by concentration

Concentration	1 mg =	U-100 units	0.5 mg	0.25 mg	0.1 mg
1 mg/mL	1 mL	100 units	50 units	25 units	10 units
2 mg/mL	0.5 mL	50 units	25 units	12.5 units	5 units
2.5 mg/mL	0.4 mL	40 units	20 units	10 units	4 units
3.33 mg/mL	0.3 mL	30 units	15 units	7.5 units	3 units
4 mg/mL	0.25 mL	25 units	12.5 units	6.2 units	2.5 units
5 mg/mL	0.2 mL	20 units	10 units	5 units	2 units
6.67 mg/mL	0.15 mL	15 units	7.5 units	3.7 units	1.5 units
10 mg/mL	0.1 mL	10 units	5 units	2.5 units	1 units
15 mg/mL	0.067 mL	6.7 units	3.3 units	1.7 units	0.7 units
20 mg/mL	0.05 mL	5 units	2.5 units	1.2 units	0.5 units
25 mg/mL	0.04 mL	4 units	2 units	1 units	0.4 units
40 mg/mL	0.025 mL	2.5 units	1.2 units	0.6 units	0.2 units
50 mg/mL	0.02 mL	2 units	1 units	0.5 units	0.2 units

1 mg in units, by vial and water

The same table, but starting from what you actually have in your hand: the mg on the vial and the mL of bacteriostatic water you added.

Vial	Water	Concentration	1 mg =
2 mg vial	1 mL	2 mg/mL	50 units
2 mg vial	2 mL	1 mg/mL	100 units
5 mg vial	1 mL	5 mg/mL	20 units
5 mg vial	2 mL	2.5 mg/mL	40 units
5 mg vial	3 mL	1.67 mg/mL	60 units
10 mg vial	1 mL	10 mg/mL	10 units
10 mg vial	2 mL	5 mg/mL	20 units
10 mg vial	3 mL	3.33 mg/mL	30 units
15 mg vial	2 mL	7.5 mg/mL	13.3 units
15 mg vial	3 mL	5 mg/mL	20 units
20 mg vial	2 mL	10 mg/mL	10 units
20 mg vial	3 mL	6.67 mg/mL	15 units
30 mg vial	2 mL	15 mg/mL	6.7 units
30 mg vial	3 mL	10 mg/mL	10 units
50 mg vial	5 mL	10 mg/mL	10 units
60 mg vial	3 mL	20 mg/mL	5 units

Micrograms to units

For peptides dosed in mcg (BPC-157, ipamorelin, sermorelin and most repair and growth-hormone peptides) the same logic applies with a thousand-fold shift. 1 mg is 1,000 mcg.

Setup	Concentration	100 mcg	200 mcg	250 mcg	500 mcg
5 mg in 1 mL	5000 mcg/mL	2	4	5	10
5 mg in 2 mL	2500 mcg/mL	4	8	10	20
5 mg in 3 mL	1667 mcg/mL	6	12	15	30
10 mg in 2 mL	5000 mcg/mL	2	4	5	10
10 mg in 3 mL	3333 mcg/mL	3	6	7.5	15
10 mg in 5 mL	2000 mcg/mL	5	10	12.5	25

Why the number changes

Units mark volume. A U-100 insulin syringe holds 100 units in 1 mL, so one unit is 0.01 mL, whatever is in the liquid. When you dissolve 10 mg of peptide in 2 mL of water you get 5 mg per mL; 1 mg of that is 0.2 mL, or 20 units. Dissolve the same 10 mg in 1 mL and it is 10 mg per mL; 1 mg is now 0.1 mL, or 10 units. The dose has not changed. Only the mark on the barrel has.

The three-step version: concentration = vial mg / water mL. Volume = dose / concentration. Units = volume x 100. If your syringe is U-40 (usually veterinary) multiply by 40 instead, and read the syringe page first, because mixing those two up is a 2.5x error.

To run it for your own numbers, in either direction, use the mg to units calculator. For a specific compound, pick it from the list of calculators.

Common questions

How many units is 1 mg on an insulin syringe?: It depends on the concentration. At 5 mg/mL (for example a 10 mg vial in 2 mL) 1 mg is 0.2 mL, which is 20 units on a U-100 syringe. At 10 mg/mL it is 10 units. At 2.5 mg/mL it is 40 units.
How many units is 0.5 mg?: Half of whatever 1 mg is at your concentration. At 5 mg/mL, 10 units. At 2.5 mg/mL, 20 units.
How many units is 1 mL?: On a U-100 insulin syringe, 100 units. On a U-40 syringe, 40 units. Units measure volume; check which scale is printed on your barrel.
How many mcg is 10 units?: Multiply the concentration in mcg/mL by 0.1. At 2,500 mcg/mL (5 mg in 2 mL), 10 units is 250 mcg.

Every calculator and chart on this site

Weight management (GLP-1 family)

Retatrutide calculator Vial, water and weekly dose to syringe units
Tirzepatide calculator The 2.5 to 15 mg ladder, converted
Semaglutide calculator The 0.25 to 2.4 mg ladder, converted
Cagrilintide calculator Amylin analogue, 0.3 to 4.5 mg weekly

Growth hormone axis

HGH (somatropin) calculator IU vials to syringe units
Ipamorelin calculator mcg doses, in mL and units
CJC-1295 (no DAC) calculator No-DAC and DAC, mcg to units
CJC-1295 / Ipamorelin blend calculator The 5 mg + 5 mg blend, per component
Sermorelin calculator Nightly mcg doses to units
Tesamorelin calculator 1 to 2 mg daily, in units
Hexarelin calculator mcg doses to units
IGF-1 LR3 calculator Tiny vials, tiny doses
AOD-9604 calculator 300 mcg daily, in units
MOTS-c calculator 5 to 10 mg, two or three times a week

Repair, skin and blends

BPC-157 calculator mcg doses from a 5 or 10 mg vial
TB-500 calculator Loading and maintenance, in units
BPC-157 / TB-500 blend calculator The Wolverine stack, per component
GHK-Cu calculator Large vials, mg doses
GLOW blend calculator The 70 mg blend, split per component
KLOW blend calculator The 80 mg blend, split per component

Other compounds

PT-141 calculator 0.5 to 2 mg, as needed
Melanotan II calculator mcg loading doses to units
NAD+ calculator Large vials, 25 to 200 mg doses
Thymosin alpha-1 calculator 1.6 mg twice weekly, in units
Epitalon calculator Short courses of 5 to 10 mg
Kisspeptin-10 calculator mcg doses to units
Glutathione calculator Large mg doses, 200 mg/mL solutions

Dosage charts and schedules

Peptide reconstitution chart Concentration for every vial and water combination
Peptide dosing chart Printable unit tables for every compound
Retatrutide titration schedule 2 to 12 mg in units, stage by stage
Tirzepatide titration schedule 2.5 to 15 mg in units, stage by stage
Semaglutide titration schedule 0.25 to 2.4 mg in units, stage by stage
KLOW dosage and frequency chart The 80 mg blend at 2, 3 and 4 mL, both phases
GLOW dosage chart The 70 mg blend, units to each peptide
Wolverine stack dosing chart BPC-157 + TB-500, blend and separate vials
MOTS-c dosage chart 5 and 10 mg vials at three water volumes
Tirzepatide reconstitution chart Every vial size, every water volume, the whole ladder
Retatrutide dosing chart 1 to 12 mg across 10, 20 and 30 mg vials

Tools

Peptide calculator The general tool, any compound
Reconstitution calculator How much water to add, and why it matters
mg to units calculator Both directions, any concentration
Bacteriostatic water calculator Pick a volume that lands where you can read it
How to read an insulin syringe U-100 vs U-40, and the 2.5x error
The Protocol Pack Free 25-page printable reference
Where to buy Vendor notes and what to check first
1 mg to units on an insulin syringe (this page)

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.