Frequently Asked Questions

ClinCalc Pro is a free clinical reference toolkit for working clinicians. It bundles 1,203 validated calculators, 3,031 drug-dose entries across 25 specialties, 508 decision pathways, and a suite of AI clinical decision support tools (differential diagnosis, prescription sanity check, polypharmacy review, investigation interpreter, tool recommender, risk stratification, and management plan drafter). Everything is statically rendered, keyboard-friendly, and works offline through the Android app.

Yes. The website and the Android app are both free, with no account required, no paywalls, and no advertising. The project is funded by voluntary donations.

ClinCalc Pro is built for qualified clinicians working in UK secondary care — junior doctors, registrars, consultants, advanced clinical practitioners, pharmacists, and nurse prescribers. It is not designed for patients or members of the public, and is not a substitute for professional medical advice.

No. ClinCalc Pro does not diagnose or treat patients. It surfaces references, calculations, and structured decision support for qualified clinicians. Final clinical decisions rest entirely with the treating clinician. See the Clinical Disclaimer for full terms.

The project is independently maintained and funded by voluntary donations from users. There are no advertisers, sponsors, or pharmaceutical industry ties. If the tools save you time, please consider donating to keep the service free.

ClinCalc Pro currently includes 1,203 clinical calculators spanning 25 specialties, including cardiology, respiratory, renal, GI, haematology, infectious disease, emergency medicine, and critical care.

Formulas are reproduced from primary publications and independently cross-checked. Each calculator links its citation, and interpretive thresholds match the published cut-offs. If a formula has multiple validated forms (e.g. Cockcroft-Gault, CKD-EPI), each is provided as a separate calculator.

Use the renal calculators on ClinCalc Pro. Cockcroft-Gault gives an estimated creatinine clearance and is still used for many drug-dose adjustments per current prescribing references. CKD-EPI 2021 gives an estimated GFR and is preferred for staging chronic kidney disease per NICE NG203. Each calculator names its source.

The HEART score is a validated risk-stratification tool for adults presenting to the emergency department with chest pain and suspected acute coronary syndrome. It scores History, ECG, Age, Risk factors, and Troponin (0–10) and helps separate low-risk from intermediate/high-risk patients. ClinCalc Pro provides the HEART calculator with its original Six et al. citation.

Yes — the Android app bundles all calculators, drugs, and pathways for offline use, which is useful in hospitals with poor signal. The website itself is a static site and loads in well under a second on mobile data once cached.

ClinCalc Pro covers 3,031 drug entries across 25 specialties, with adult, paediatric, and neonatal dosing where applicable.

Current UK formularies and prescribing references (covering adults, children and neonates) are the primary source. Doses are corroborated against NICE TAs/NGs/CKS, MHRA Drug Safety Updates, and specialty guidelines from ESC, ESMO, BSH, BSAC, UKHSA, BHIVA, EASL, RCOG, RCOphth, BAD, NOGG, and BSG where applicable. Always verify against your local formulary before prescribing.

Yes. Where a children's formulary or a neonatal formulary specifies a dose, it is included alongside the adult dose with the relevant age, weight, or postmenstrual age band. Paediatric and neonatal entries are clearly labelled.

Drug content is reviewed against current prescribing references on a rolling basis. MHRA Drug Safety Updates and major NICE/ESC guideline changes are applied as they are published. Reported errors are reviewed within 24 hours.

Please tell us via the contact page. Drug-dose corrections are prioritised and reviewed within 24 hours. Include the drug name, the dose shown, the dose you believe is correct, and the source you are quoting.

A pathway is a branching decision tree that walks you through a clinical scenario step by step — for example, suspected pulmonary embolism, acute upper-GI bleed, or new-onset atrial fibrillation. Each branch ends with a structured recommendation tied to a named guideline.

Pathways are aligned to the relevant UK and international guideline body — NICE, ESC, AHA, BTS, ATS, GOLD, KDIGO, BSG, BSH, BHIVA, RCOG, and others. The originating guideline is named on every pathway page so you can cross-check the source.

Calculators take inputs and return a score, dose, or risk estimate. Pathways are decision trees that guide you through a sequence of clinical questions and end with a recommended action. They are complementary — many pathways embed a calculator step.

No. Pathways summarise national and international guidance for fast bedside reference, but local trust protocols and formularies always take precedence. Pathways support clinical decision-making — they do not replace clinical judgement or local policy.

AI Differential is a structured-output assistant that takes a presenting complaint, key history, and red-flag information and returns a ranked differential, suggested investigations, and red-flag warnings. It is decision support only — it does not diagnose or treat.

It is powered by Anthropic's Claude Sonnet 4.5 (claude-sonnet-4-5-20250929) with a structured-output system prompt. Selecting a specialty swaps in a focused lens — for example, Cardiology uses HEART/GRACE framing, Neurology uses NIHSS/ABCD2, Respiratory uses Wells/PERC.

The proxy receives only the fields you enter and forwards them to Anthropic. Patient-identifiable information must not be entered. Requests are not logged with content; only IP-level rate-limit counters and aggregate token usage are kept. Treat the input box as you would any external clinical tool — anonymised data only.

Yes. AI Differential is capped at 5 requests per IP address per UTC day, with a global daily cost guardrail. The cap keeps the tool free and prevents abuse. The limit resets at 00:00 UTC.

No. It generates a structured differential and red-flag list to support clinical reasoning. It is not a diagnostic device, has no access to the patient, and does not replace examination, investigation, or specialist input. Final decisions rest with the treating clinician.

AI credits let you use the 7 ClinCalc Pro AI tools beyond the free 5 calls per IP per day. Each pack purchase generates an opaque token that grants a fixed number of additional calls across all 7 AI tools. The free tier is unchanged — credits are an opt-in top-up for heavy users.

No. ClinCalc Pro deliberately has no accounts. When you pay, the server issues a 48-character random token that is the only credential. It is stored in your browser's localStorage and never tied to your name or email on our side. Stripe holds your payment email — we do not.

No. Every purchase is one-off — you buy a fixed pack (25, 100, or 300 calls), the credits never expire, and there is no recurring charge. When the pack runs out, buy another only if you need to.

Only in your browser's localStorage on this device, under the key clincalc_ai_credit_token_v1. Each AI request sends the token in an X-AI-Credits-Token header. The server checks the remaining balance and decrements after a successful call. The token never leaves your browser except in those API requests.

Yes, if you still have your Stripe receipt. Go to /manage-credits/, paste your Stripe Checkout Session ID or Payment Intent ID (both visible in your receipt email from Stripe), and the server will return your token. You can also copy a token between devices manually — paste it on the same page to install it on a new browser.

Yes — the token is portable. Copy it from one browser, paste it into /manage-credits/ on another, and that device now uses the same credit pool. Each call decrements the shared balance regardless of which device made the request.

Yes — 100 calls per 24-hour window per token. This is a safety cap to prevent accidental burn-throughs and absorb cache-miss spikes. It rolls automatically; it does not consume credits.

Credits are a digital good delivered instantly. We do not offer routine refunds. If your token never worked or your purchase was duplicated, contact us and we will investigate. Disputes filed through your card issuer void the corresponding token.

Yes. Stripe sends a receipt to the email you provide at checkout. We do not store your email on our servers.

No. There is no sign-up, no login, and no user profile. All tools are accessible directly from the website or the Android app.

If you accept the analytics cookie, Google Analytics 4 records anonymous, IP-anonymised page-view counters. If you decline, no analytics data is collected. The AI Differential proxy stores IP-level rate-limit counters only — no request content.

ClinCalc Pro uses one optional analytics cookie for anonymous page-view counts. It is opt-in via the consent banner on first visit, and your choice is remembered locally. Declining the cookie does not affect any feature on the site.

Drug doses and pathways are written for UK secondary-care practice and reference UK guidelines and formularies (including NICE) as primary sources. Calculators and risk scores are universal, but always cross-check drug doses and pathway recommendations against your local formulary and national guidelines if practising outside the UK.

Not yet. The full website works in mobile Safari and is installable as a Progressive Web App. A native iOS app is on the roadmap but not committed to a date.

Visit the Get the App page on ClinCalc Pro for the current Play Store link and installation instructions. The Android app bundles all calculators, drugs, and pathways for offline use.

ClinCalc Pro is a static site built with Astro — every page is pre-rendered to HTML at build time, with minimal JavaScript and aggressive code-splitting. Pages typically load in under a second on mobile data once cached.

Use the contact page. Bug reports, dose corrections, missing references, and feature requests are all welcome. Drug-dose corrections are reviewed within 24 hours; other items are triaged weekly.