MATH · FREE
Peptide Calculator
A peptide reconstitution calculator for vial and syringe math: concentration, mL to draw and units on a U-100 insulin syringe.
Math only. Not medical advice. Does not recommend doses. Follow your prescriber's instructions.
DRAW ON A U-100 SYRINGE
Concentration
Per syringe unit
of peptide in 1 unit
Volume to draw
Doses per vial
whole doses, rounded down
Math only. Not medical advice. Does not recommend doses. Follow your prescriber's instructions. Always check the numbers against your prescriber's or product's instructions.
AFTER YOU MEASURE
Measured it? Log the dose.
Log the dose and rotate injection sites in Orbido, a private log and reminder app for iPhone. No account, data stays on your device. Orbido is a logging tool, not medical advice.
Quick converters
Units ↔ mL (U-100)
mg ↔ mcg
How the math works, step by step
This worked example uses made-up numbers to show the arithmetic. It is not a suggested dose. Say a vial holds 5 mg of powder, you add 2 mL of bacteriostatic water, and the dose you were given is 250 mcg.
- Concentration. 5 mg ÷ 2 mL = 2.5 mg/mL, which is 2,500 mcg per mL.
- Volume to draw. 250 mcg ÷ 2,500 mcg/mL = 0.1 mL.
- Syringe units. A U-100 syringe has 100 units per mL, so 0.1 mL × 100 = 10 units.
- Per unit. 2,500 mcg/mL ÷ 100 units/mL = 25 mcg in each unit.
- Doses per vial. 5,000 mcg ÷ 250 mcg = 20 doses.
Insulin syringe units to mL
On a U-100 insulin syringe, 100 units equal 1 mL, so 1 unit is 0.01 mL. Smaller syringes are the same scale, just shorter: a 0.5 mL syringe tops out at 50 units and a 0.3 mL syringe at 30 units. Smaller barrels have finer marks, which makes small volumes easier to read.
Units to mg
There is no single answer, because a unit is a volume and the strength depends on how much water you added. Divide the vial's mg by the mL of water to get mg per mL, then divide by 100 to get mg per unit. The calculator above reports this as mcg per unit.
The rules about who may buy, prescribe or use a given peptide differ by country and by compound. This page does not take a side on that. It only does arithmetic on numbers you provide.
Calculators for specific products
The same arithmetic with pages that explain the math for one product. They never suggest an amount.
Frequently asked questions
How does a peptide reconstitution calculator work?
It does division. Concentration is the amount of peptide in the vial divided by the volume of water you add. The volume to draw is your dose divided by that concentration. 5 mg in 2 mL is 2.5 mg/mL, so a 250 mcg dose is 0.1 mL.
What does U-100 mean on an insulin syringe?
U-100 means 100 units equal 1 mL. A 1 mL syringe holds 100 units, a 0.5 mL syringe holds 50 units and a 0.3 mL syringe holds 30 units. The unit marks measure volume, not medicine strength.
How do I convert insulin syringe units to mL?
Divide the units by 100. 10 units is 0.1 mL and 25 units is 0.25 mL. To go the other way, multiply mL by 100.
Are syringe units the same as mg or mcg?
No. Units are a volume mark on the syringe barrel. How many mcg a unit holds depends on the concentration of your vial: mcg per unit = (mg in the vial ÷ mL of water) × 1000 ÷ 100. The calculator shows this number for you.
How many mcg are in 1 mg?
1 mg is 1,000 mcg. So 0.25 mg is 250 mcg and 2.5 mg is 2,500 mcg.
How many doses are in a vial?
Total peptide in the vial divided by one dose, rounded down. A 5 mg (5,000 mcg) vial and a 250 mcg dose gives 20 doses. This ignores any volume lost in the needle or on the stopper.
Why does the calculator warn about fewer than 2 units?
Very small draws are hard to read on the syringe marks, so a small error is a large share of the dose. Adding more water lowers the concentration and makes the same dose a bigger, easier volume.
Does this calculator tell me what dose to take?
No. It never suggests, recommends or fills in a dose. You enter the vial amount, the water and the dose given by your prescriber or on your product label, and it does the arithmetic.
Is my information saved?
No. The calculation runs in your browser. Nothing you type is uploaded or stored.
Math only. Not medical advice. Does not recommend doses. Follow your prescriber's instructions.