The Decision

Three questions.
The answers pick your calculator.

You don't need to read a 3,000-word comparison. Answer three questions and you'll know which calculator fits your protocol.

The Questions

Which Calculator for You

Are you on Android?

PeptideCalc, PepTracker, and Dose are iOS only. Protocol is the only full-featured peptide calculator on Android as of June 2026. If you're on Android, the answer is Protocol.

Protocol

Do you need Custom Draw, TRT, or PK tools?

Custom Draw reverse mode, the TRT ester calculator, and the PK half-life plotter exist only in Protocol. If any of these matter to your protocol, the choice is made.

Protocol

Do you want iCloud sync and iPad support?

Protocol is on-device only — no cloud sync. PeptideCalc syncs across iPhone and iPad via iCloud. If you actively use both devices and want sync, PeptideCalc is worth evaluating.

PeptideCalc

"If none of those three conditions apply, both apps will serve you — Protocol is free and PeptideCalc costs money."

For most users the answer is Protocol: it's more capable, it's free, and it runs on Android. The only clear win for PeptideCalc is multi-device iCloud sync across iPhone and iPad — a genuinely useful feature that Protocol doesn't offer. Outside of that specific use case, Protocol does more for nothing.

The Full Suite

What Protocol's Five Tools Cover

Reconstitution calculator

Standard forward calculation — vial size, BAC water, dose → concentration, draw units, mL, doses per vial.

Protocol

Custom Draw (reverse mode)

Specify the syringe draw you want, get the BAC water volume to produce it. Only free calculator with this feature.

Protocol only

PK half-life plotter

Blood concentration curves for 22 compounds, up to 4 simultaneous, dose superposition math.

Protocol only

TRT ester calculator

Free testosterone content across 6 testosterone esters. 200mg Cypionate is ~140mg actual T.

Protocol only

Stack cost calculator

Monthly and cycle cost across your full multi-compound protocol. Only free tool of its kind.

Protocol only

Common Questions

FAQ

Is there a peptide calculator I can use on my phone without downloading an app?
Yes. Protocol's reconstitution calculator and Custom Draw mode are available free on the web at reconstitution.health — no download required. The PK plotter, TRT ester calculator, and stack cost calculator require the Protocol app (free on iOS and Android). All web tools require no account.
Which peptide calculator is best for GLP-1 users?
Protocol is the best GLP-1 calculator. It includes a semaglutide concentration calculator (for compounded forms in varying vial sizes), the Custom Draw mode that's useful as dose titrates week-to-week, and full injection tracking and dose logging. The web calculator handles any compounded GLP-1 concentration math directly at reconstitution.health. Available on Android — the only full-featured option for Android GLP-1 users.
Does Protocol work offline?
Yes. Protocol stores all data on-device and the calculator tools work without an internet connection. The reconstitution calculator, Custom Draw mode, and all other calculation tools function fully offline. The web version at reconstitution.health requires an internet connection since it runs in a browser.

All Five Calculators. Free.

Custom Draw · PK Plotter · TRT Ester · Stack Cost · iOS + Android

App Store Google Play

No account · On-device only · iOS + Android