Peptide Calculator

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.
Free: the Protocol Pack, 25 printable pages. A dosing card for every compound on this site at three water volumes, titration planners, a vial log, and five pages on what to do when you have already got it wrong.
The download appears right here. No account, no spam, one-click unsubscribe.
IndependentThis site does not sell peptides and is not owned by a vendor. Every other calculator on page one of Google belongs to a shop.
The maths is openThe formula is written out on this page and the code behind it is a single file with an automated test suite .
How it earnsAffiliate links on one clearly marked page, and nowhere else. Never inside the calculator.
ReviewedDose ranges and half-life figures last checked 3 September 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

VialBAC waterConcentrationDrawU-100 unitsDoses/vial
5 mg1 mL5 mg/mL0.2 mL20 units5
5 mg2 mL2.5 mg/mL0.4 mL40 units5
5 mg3 mL1.67 mg/mL0.6 mL60 units5
10 mg1 mL10 mg/mL0.1 mL10 units10
10 mg2 mL5 mg/mL0.2 mL20 units10
10 mg3 mL3.33 mg/mL0.3 mL30 units10
20 mg1 mL20 mg/mL0.05 mL5 units20
20 mg2 mL10 mg/mL0.1 mL10 units20
20 mg3 mL6.67 mg/mL0.15 mL15 units20
30 mg1 mL30 mg/mL0.033 mL3.3 units30
30 mg2 mL15 mg/mL0.067 mL6.7 units30
30 mg3 mL10 mg/mL0.1 mL10 units30

All rows above assume a 1 mg dose and a standard U-100 insulin syringe, where 100 units = 1 mL.

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.

Every calculator and chart on this site

Weight management (GLP-1 family)

Growth hormone axis

Repair, skin and blends

Other compounds

Dosage charts and schedules

Tools

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.