2026 Guide — Free & Paid Options
There are six distinct peptide calculator types. Most apps include one or two. One free app includes all six. This guide explains the difference, who needs what, and where to find it.
Who needs what
Reconstituting a peptide
Reconstitution Calculator
Enter your peptide in mg and your target dose in mcg. The calculator returns exact BAC water volume and resulting concentration per unit. Available in every app and at reconstitution.health.
Want a specific syringe draw
Custom Draw Mode
Tell it how many units you want to draw — it tells you how much BAC water to add to hit that draw at your dose. Only available in Peptide Calculators and Protocol. No other app has this.
On TRT
TRT Ester Calculator
Your prescribed dose in mg is not your testosterone dose in mg. The ester accounts for 30–40% of molecular weight. This calculator shows actual free testosterone across 6 esters.
Using semaglutide or tirzepatide
GLP-1 Concentration Calculator
Compounded GLP-1 vials vary in size and concentration. Enter your vial size and BAC water volume — get dose per unit for your titration schedule. Handles both semaglutide and tirzepatide.
Planning a stack or cycle
Stack Cost Calculator
The only free calculator that shows total protocol cost — per vial, per week, per month — across multiple compounds. No other app builds this.
Timing multiple compounds
PK Half-Life Plotter
Plot active plasma levels for up to 4 compounds simultaneously with real one-compartment kinetics and dose superposition. 22 compounds in the database.
Feature comparison — 2026
Which apps include which calculators, and what each one costs.
| Calculator | Peptide Calculators FREE · iOS + Android |
PeptideCalc.io $9.99 · iOS only |
Dose App Freemium · iOS only |
Hacksmith Peptalk Free · Web only |
PepTracker Freemium · iOS only |
|---|---|---|---|---|---|
| Reconstitution Calculator | ✓ | ✓ | ✓ | ✓ | ✓ |
| Custom Draw Mode | ✓ Only | — | — | — | — |
| PK Half-Life Plotter | ✓ 22 compounds | ✓ Basic | ✓ Basic | — | — |
| TRT Ester Calculator | ✓ 6 esters | — | — | — | ✓ Basic |
| GLP-1 Calculator | ✓ | — | — | — | — |
| Stack Cost Calculator | ✓ Only | — | — | — | — |
| Android | ✓ | — | — | ✓ Web | — |
| Price | Free | $9.99 one-time | Freemium | Free web | Freemium |
In depth
All six are free in the Peptide Calculators app for iOS and Android.
01
Reconstitution Calculator
CoreDissolves a lyophilized peptide in bacteriostatic water at the right concentration. Enter peptide mg and target dose in mcg — get exact BAC water volume and units per dose. The starting point for every peptide protocol.
02
Custom Draw Mode
Unique to this appWorks backwards from your preferred syringe draw. Specify how many units you want to pull — 10, 20, a round number that's easy to read — and the calculator tells you the exact BAC water volume to add so that draw delivers your dose. No other free app has this.
03
PK Half-Life Plotter
AdvancedPlots active plasma levels for up to 4 compounds simultaneously using one-compartment first-order kinetics with dose superposition. 22 compounds in the database. Shows how levels accumulate across multiple injections over your dosing schedule — not just a single-dose decay curve.
04
TRT Ester Calculator
TRTYour TRT prescription is written in compound mg, not testosterone mg. Testosterone Cypionate is about 69.9% testosterone by molecular weight — 200mg delivers roughly 140mg of actual T. This calculator shows the real testosterone content across 6 esters at any prescribed dose.
05
GLP-1 Concentration Calculator
GLP-1Compounded semaglutide and tirzepatide come in variable vial sizes from different pharmacies. Enter your vial size in mg and BAC water volume — get concentration per unit and dose verification across your weekly titration schedule. Handles both molecules.
06
Stack Cost Calculator
Unique to this appThe only free peptide protocol cost calculator. Enter your compounds, doses, frequency, and vial sizes — get total cost per vial, per week, and per month across your entire stack. No other free app builds this.
Several sites offer free web-based peptide calculators — no download required. Good for one-off calculations before you order.
All six calculators in one place, offline-capable, no account, nothing leaves your device. The same calculation engine as the web tools with a better interface and iOS/Android optimization.
What is the best free peptide calculator?
The Peptide Calculators app by IMA, LLC is the most complete free peptide calculator available. It includes six calculators — reconstitution, Custom Draw, PK half-life, TRT ester, GLP-1, and stack cost — on iOS and Android at no cost. PeptideCalc.io charges $9.99 for a subset of these tools and is iOS-only. Web options exist for individual calculators at reconstitution.health, glp1tracker.health, and trttracker.health.
Is there a peptide calculator for Android?
Yes. Peptide Calculators is available on Android — it is the only free full-featured peptide calculator app on Android. PeptideCalc.io is iOS only. Dose is iOS only. PepTracker is iOS only. Hacksmith Peptalk is web-based and works on any device with a browser, but does not have Custom Draw, TRT ester, or stack cost calculators.
How much BAC water do I add to reconstitute a peptide?
It depends on the peptide amount and your target dose. There is no universal answer — the right BAC water volume is whatever produces a concentration where your target dose draws a convenient, accurate volume on your syringe. A reconstitution calculator determines this precisely for your specific situation. A common starting point is 2mL BAC water per 5mg vial, but this is not a rule — it depends entirely on what you are trying to dose.
What is Custom Draw mode?
Custom Draw is a reverse reconstitution calculator. Instead of specifying BAC water volume and getting a resulting dose per unit, you specify the dose per unit you want to draw — such as 10 units on a U-100 syringe — and get the exact BAC water volume to add to produce that result. It is useful because certain draws are easier to read and measure accurately than others. Only the Peptide Calculators app and the Protocol app have this feature.
What is the difference between Peptide Calculators and Protocol?
Peptide Calculators is a standalone calculator suite — six tools for math. Protocol is a full tracking app that includes all six calculators plus dose logging, injection site rotation with a 3D body map, bloodwork tracking, AI analysis, 81 compound research profiles, and cycle planning. Protocol is $7.99/month. Peptide Calculators is free.
Why is 200mg of Testosterone Cypionate not 200mg of testosterone?
Testosterone ester compounds are weighed and dosed as the complete molecule — testosterone plus the ester chain attached to it. The ester is cleaved off after injection by plasma esterases and plays no hormonal role. Testosterone Cypionate has a molecular weight where the testosterone fraction is approximately 69.9% of the total. So 200mg of Testosterone Cypionate delivers about 140mg of bioavailable testosterone. The TRT ester calculator shows this conversion across six common esters.
Beyond the calculator
Every calculator in this app, plus dose logging, injection site rotation, bloodwork tracking, AI stack analysis, 81 compound profiles, and cycle planning. The only full-featured peptide tracking app on Android. Built by IMA, LLC.
$7.99 / month