9 Best Peptide Calculators & Tracking Apps (2026)

* Free with an optional one-time lifetime unlock. ✅ = yes · ~ = partial · ❌ = no.

Best for: anyone who wants the calculator and tracking in one place, in their own language, without paying up front.

Peptide Lab is our own free web app, so treat this as a disclosed recommendation — but the comparison below is honest about where it loses. It combines a reconstitution calculator (with a suggested-water hint), injection logging with a tap-to-select body map for site rotation, weight and side-effect tracking, a half-life visualizer, and a 10-chapter reconstitution guide. It runs in any browser with nothing to install, and it's the only tool here available in 12 languages.

• Strengths: everything in one place; genuinely free (optional $19.99 lifetime unlock, no subscription); 12 languages; no install; built-in guide.
• Honest limitations: it's a web app, so it can't match a native app's offline use and push notifications, and there's no App Store listing or wearable/bloodwork sync yet. If you want a phone-native experience above all, see the apps below.

Best for: users who want a polished native app on iOS or Android and don't mind paying for the advanced features.

PeptIQ is the closest all-in-one rival: reconstitution and dosing calculators, injection logging with body-map site rotation, a large peptide-profile library, and integrations with Apple Health, Google Fit and wearables. Its calculator and basic logging are free; the half-life tracker, smart low-stock reminders and stack tools sit behind a Premium subscription.

• Strengths: native iOS + Android + web; body map; wearable and bloodwork sync; deep peptide library.
• Trade-offs: the most useful features are paywalled; English only; more complex to get started.

Best for: Apple users who want dose history and medication-level modeling, not just a calculator.

A well-made iOS/iPadOS app with reconstitution math, broad unit support, dose-history logging, unlimited saved protocols, reminders, and standout half-life / medication-level modeling with Apple Health and iCloud sync. One-time purchase, no ads or subscriptions.

• Strengths: excellent half-life modeling; Apple ecosystem integration; one-time price.
• Trade-offs: iOS only (no Android or web); no body-map rotation; English only.

Best for: people who only want fast, private reconstitution math on either iPhone or Android.

PepCalc is a focused, offline calculator available on both iOS and Android (rare in this niche). It handles reconstitution, dose-to-units conversion, multiple peptides in one vial, a water solver and syringe presets — all with a one-time purchase and no signup. It deliberately does nothing else: no logging, no body map, no education.

• Strengths: works fully offline; on both platforms; clean UX; one-time price.
• Trade-offs: calculator only — no tracking or guidance; English only.

Best for: frequent injectors who care most about rotating sites correctly to avoid tissue damage.

These native apps are built around a visual body map: tap the exact spot, see color-coded rest status, and get the next-site suggestion automatically. This is the one area where a phone app genuinely beats a web tool — tap-on-body interaction feels better on a touchscreen. DoneDose is iOS (freemium); Smart Peptide Tracker is the strongest Android option (one-time purchase).

• Strengths: best-in-class, tap-exact site rotation with per-compound history.
• Trade-offs: narrow focus; thin on reconstitution and education; single-platform; English only.

Best for: users who want the tracker with the most reviews and social proof behind it.

PepTracker (iOS plus a web companion) is the most-reviewed dedicated peptide tracker, with a strong rating across a few hundred reviews. It logs multiple compounds, does reconstitution math, sends reminders and syncs across devices. Its site rotation is general-area rather than tap-exact, and the deeper features are subscription-based.

• Strengths: proven traction and reviews; cross-device; reliable reminders.
• Trade-offs: subscription; coarser site rotation; English only.

Best for: weight-loss users focused specifically on GLP-1 peptides who need dose-escalation schedules.

A wave of dedicated GLP-1 tools (glp1calculator.com, Fat Scientist's calculator, and others) do reconstitution plus something the general tools don't: titration/escalation schedulers and plasma-accumulation curves tuned for semaglutide, tirzepatide and retatrutide. If GLP-1s are your entire use case, these niche tools are genuinely useful. They're free (affiliate-funded) but narrow — not built for research-peptide breadth.

Best for: a fast, no-signup calculation when you don't need to save anything.

These are the tools most people mean when they Google "peptide reconstitution calculator": instant, browser-based, zero friction. Many are run by vendors as lead-gen, and one (Rite Aid's) even carries real brand authority. They do the math well but nothing more — no persistence, no tracking, no education, English only.

• Strengths: instant; no account; ubiquitous.
• Trade-offs: single-purpose; nothing is saved; vendor calculators are product funnels.

Best for: experienced users who want full control and to own their data.

Community-shared Google Sheets and Excel templates remain a common "starter" tool, especially on peptide forums. They're free, endlessly customizable, and you own the file — but they're manual, error-prone, have no guardrails or mobile UX, and the links are ephemeral. Treat them as a personal log, not a calculator you can trust blindly.

• Just need the math, once? A free web calculator — or our own peptide calculator.
• Want calculator + tracking in one place, free, in your language? Peptide Lab.
• Live in a native app and will pay for depth? PeptIQ (all-in-one) or PeptideCalc.io (iOS + half-life).
• Care most about site rotation? DoneDose or Smart Peptide Tracker.
• Only doing GLP-1s? A dedicated GLP-1 titration calculator.