Free Calculator

Peptide Reconstitution
Calculator

Three inputs. Four outputs. The full reconstitution calculation — including Custom Draw reverse mode — is free at reconstitution.health and in the Protocol app.

The Calculation

What the Calculator Gives You

A peptide reconstitution calculator takes three inputs — vial size in mg, bacteriostatic water volume in mL, and target dose in mcg — and returns four outputs: solution concentration in mcg/mL, syringe draw units for a U-100 insulin syringe, draw volume in mL, and total doses per vial. The math is a single formula applied twice, but the calculation determines the accuracy of every injection you take from that vial.

The Formula

Concentration (mcg/mL) = Vial size (mcg) ÷ BAC water (mL)

Draw units = (Dose mcg ÷ Concentration) × 100

Example: 5mg vial + 2mL BAC water = 2,500 mcg/mL. For 250mcg dose: 10 units on a U-100 syringe. For 500mcg: 20 units.

Protocol's Custom Draw mode inverts this calculation: specify the syringe draw units you want per dose and get the BAC water volume needed to produce that draw. This is the only free calculator that operates in both directions. Available at reconstitution.health with no download required.

Reference

Common Vial Configurations

VialBAC WaterConcentration250mcg500mcg1mg
5mg2mL2,500 mcg/mL10u20u40u
5mg4mL1,250 mcg/mL20u40u80u
10mg4mL2,500 mcg/mL10u20u40u
2mg1mL2,000 mcg/mL12.5u25u50u
2mg2mL1,000 mcg/mL25u50u—

Highlighted draws are in the 10–25 unit range — optimal for measurement accuracy on a U-100 syringe. "u" = units.

FAQ

Calculator Questions

Where is the free peptide reconstitution calculator?
The free reconstitution calculator is at reconstitution.health — no download, no account. Enter vial size (mg), BAC water volume (mL), and target dose (mcg) to get concentration, draw units, mL draw, and doses per vial. Custom Draw mode is also available there — specify target draw units and get the BAC water amount needed.
What is Custom Draw mode?
Custom Draw reverses the standard calculation. Instead of entering BAC water volume and getting draw units as an output, you specify the draw units you want per dose as an input and the calculator returns the BAC water volume to add. This is useful when you want a specific draw unit (like exactly 20 units for readability) and want to build your reconstitution around that target.
Does the calculator work for semaglutide and tirzepatide?
Yes. The reconstitution calculator works for any lyophilized peptide or compound that requires BAC water reconstitution — including compounded semaglutide and tirzepatide. Enter the labeled vial size (2mg, 5mg, 10mg are common for GLP-1 compounds), your chosen BAC water volume, and your current titration dose in mcg. The Custom Draw mode is particularly useful for GLP-1 users since vial sizes change frequently during titration.

Free Reconstitution Calculator

Custom Draw mode · No download · Web + iOS + Android

App Store Google Play

Web: reconstitution.health · No account required