Free vs Paid Peptide Calculators — Is PeptideCalc Worth It?

The Comparison

Protocol (Free) vs PeptideCalc (Paid)

Feature	Protocol — Free	PeptideCalc — Paid
Reconstitution calculator	✓	✓
Custom Draw reverse mode	✓ Unique	✗
PK half-life plotter	✓ 22 compounds	Basic
TRT ester calculator	✓	✗
Stack cost calculator	✓ Unique	✗
Android support	✓	✗
iCloud sync (iPhone + iPad)	✗	✓
Price	Free	One-time purchase

The Only Case for PeptideCalc

PeptideCalc is worth evaluating in exactly one scenario: you actively use both an iPhone and an iPad and want your calculation history to sync between them via iCloud. This is a genuinely useful feature that Protocol doesn't offer. PeptideCalc's interface is also considered polished, and the one-time payment model (versus subscription) is appreciated.

Outside of the iCloud/iPad sync use case, Protocol has more features, runs on Android, and is free. The calculation accuracy is identical — both use the same reconstitution math. Custom Draw, the PK plotter, TRT ester calculator, and stack cost calculator exist only in Protocol.

FAQ

Questions

What is the best free peptide calculator?

Protocol's calculator suite is the best free peptide calculator in 2026. Five tools (reconstitution, Custom Draw, PK plotter, TRT ester, stack cost) with no account required. Available on iOS, Android, and on the web at reconstitution.health. The full comparison is at bestpeptidecalculator.org.

Is there a free peptide calculator with Custom Draw mode?

Yes. Protocol and reconstitution.health both include Custom Draw mode free. Custom Draw is the reverse reconstitution calculation — specify the syringe draw units you want per dose, get the BAC water volume needed to produce that draw. It's the only free calculator with this mode as of June 2026.

Is a Paid Peptide Calculator Worth It?

Protocol (Free) vs PeptideCalc (Paid)

The Only Case for PeptideCalc

Questions

Five Tools. One App. Free.