There is a quiet problem with clinical calculators that every UK doctor has encountered but few talk about. You are in a GP consultation. A patient's QRISK3 needs calculating. You open a calculator site, and the default is the ACC/AHA Pooled Cohort Equations — an American tool that uses different thresholds, different risk factors, and different treatment initiation recommendations from NICE. You find the QRISK3 calculator eventually, but the result comes with no guidance on what to do next. No NICE threshold. No statin recommendation. Just a number.
Or you are on a post-take ward round. The consultant asks for the CURB-65. You open a calculator app, get the score, but the interpretation text references American Thoracic Society guidelines rather than the BTS/NICE pathway that governs your hospital's pneumonia protocol. The score is correct. The clinical context is wrong.
This is the problem iatroX Calculators solves. 80+ clinical calculators built specifically for UK practice — with NICE-referenced interpretation, BNF-aligned thresholds, clinical pearls on every tool, and semantic search that finds the right calculator in under 3 seconds.
The Problem With Existing Calculator Sites
The dominant clinical calculator platforms — MDCalc, Calculate by QxMD, and various app-based tools — were built for the US market. They are good tools. The calculations are accurate. But the clinical context defaults to American guidelines.
When MDCalc tells you a CHA₂DS₂-VASc score of 2 in a male requires anticoagulation, the treatment recommendation references ACC/AHA/HRS guidelines. In UK practice, the threshold and the recommended anticoagulant options follow NICE NG196 — and the nuances (when to choose a DOAC vs warfarin, when to consider left atrial appendage occlusion) are different.
When a calculator gives you a Wells PE score of 5, the next step in the US is typically a CTPA. In UK practice, the next step depends on whether you are following the NICE NG128 pathway or your local trust protocol — and the age-adjusted D-dimer threshold that determines whether imaging is needed at all varies between systems.
The calculation is universal. The clinical decision that follows is jurisdiction-specific. And for UK doctors, the jurisdiction is NICE, BNF, SIGN, and RCGP — not ACC/AHA.
Beyond the guideline alignment, there is the user experience problem. Most calculator sites are ad-supported. Scrolling past banner ads to find an input field while a patient is in front of you is not acceptable clinical practice. And finding the right calculator in the first place often means scrolling through alphabetical lists of 600+ tools, most of which you will never use.
What iatroX Calculators Does Differently
Semantic Search — Find Any Calculator in Under 3 Seconds
Type "liver fibrosis" into the iatroX calculator search and you get FIB-4, NAFLD Fibrosis Score, and Child-Pugh instantly. Type "PE risk" and you get Wells PE, PERC, YEARS, Geneva, sPESI, and age-adjusted D-dimer. Type "blatchford" or "GI bleed" and Glasgow-Blatchford surfaces immediately.
The search is semantic — it understands clinical concepts, not just calculator names. You do not need to remember that the upper GI bleed risk score is called "Glasgow-Blatchford." You type what you are clinically thinking about, and the relevant tools appear.
UK-Contextualised Guidance on Every Result
Every calculator result on iatroX comes with interpretation that references the UK guideline. A QRISK3 score of 12% does not just display "moderate risk" — it tells you this exceeds the NICE CG181 10% threshold for offering atorvastatin 20mg, references the shared decision-making framework, and notes the relevant lifestyle modification recommendations.
A CURB-65 score of 2 does not just say "moderate severity" — it references the BTS/NICE community-acquired pneumonia pathway, indicates that hospital admission should be considered, and notes the recommended antibiotic regimen per local guidance principles.
A CHA₂DS₂-VASc score of 2 in a male does not just say "anticoagulation recommended" — it references NICE NG196, notes that a DOAC is first-line over warfarin for most patients, and flags the situations where warfarin remains preferred (mechanical heart valves, severe mitral stenosis).
Clinical Pearls on Every Tool
Every calculator page includes clinical pearls — the practical insights that textbooks omit but experienced clinicians know. The Wells PE calculator notes that the "alternative diagnosis less likely" criterion is the most subjective and the most commonly misapplied. The NEWS2 page explains the Scale 2 issue for COPD patients and the single-parameter-of-3 trigger that junior doctors consistently forget. The PHQ-9 page flags what to do when item 9 (suicidal ideation) is positive — the specific safety assessment step that the score alone does not address.
Cross-Linked Related Calculators
Clinical decisions rarely involve a single score. PE workup might require Wells PE → then sPESI for risk stratification → then age-adjusted D-dimer for the intermediate-probability group. Liver assessment might flow from FIB-4 → NAFLD Fibrosis Score for indeterminate results → Child-Pugh for staging if cirrhosis is confirmed → MELD for transplant assessment.
Every calculator on iatroX links to the related tools in the clinical workflow — so you flow naturally from one score to the next without searching again.
No Ads. No Clutter.
iatroX Calculators is free and ad-free. No banner ads between the input fields. No pop-ups while you are calculating a Glasgow Coma Scale during a trauma call. The interface is clean, mobile-optimised, and designed for the reality of clinical use — which is that you need the answer in seconds, on a phone, often while a patient is in front of you.
Worked Examples
Scenario 1 — GP consultation: Cardiovascular risk assessment. A 58-year-old male smoker with hypertension and a total cholesterol of 6.2 asks whether he needs a statin. Open iatroX Calculators, type "QRISK3." Enter the variables. Result: 14.2% ten-year CVD risk. The interpretation panel tells you this exceeds the NICE CG181 10% threshold, recommends offering atorvastatin 20mg after a shared decision-making conversation, and notes that lifestyle modification should be discussed regardless. You have the answer, the guideline reference, and the clinical recommendation in under 30 seconds — without leaving the consultation.
Scenario 2 — Emergency department: PE workup. A 42-year-old woman presents with pleuritic chest pain and mild tachycardia. Open iatroX Calculators, type "PE." Select Wells PE score. Enter clinical findings: heart rate >100 (1.5 points), clinical signs of DVT absent, haemoptysis absent, malignancy absent, immobilisation absent, previous PE absent, alternative diagnosis more likely (0 points). Score: 1.5 — PE unlikely. The interpretation references the NICE NG128 pathway: proceed with D-dimer. The page cross-links to the age-adjusted D-dimer calculator for the next step. One flow, two calculators, no re-searching.
Scenario 3 — Ward round: Liver fibrosis screening. A patient with NAFLD and mildly elevated ALT. The consultant asks for a FIB-4. Open iatroX Calculators, type "FIB-4." Enter age, AST, ALT, platelets. Result: 1.8 — indeterminate. The interpretation references the NICE NG49 NAFLD pathway: an indeterminate FIB-4 (1.30-2.67) warrants further assessment — consider NAFLD Fibrosis Score or referral for FibroScan/ELF test. The page cross-links directly to the NAFLD Fibrosis Score calculator. You calculate it immediately. NFS result confirms intermediate risk. The guidance recommends hepatology referral for non-invasive fibrosis assessment. The clinical pathway is complete — two calculators, one workflow, referenced to NICE throughout.
Scenario 4 — On-call: Sepsis screening. A patient on the ward triggers a NEWS2 of 7. The nurse bleeps you. You need to determine whether this meets the sepsis screening threshold. Open iatroX Calculators, type "NEWS2." The clinical pearl immediately confirms: NEWS ≥5 triggers the sepsis screening pathway per NICE NG51. The page cross-links to qSOFA and SOFA for further stratification if needed.
What Is in the Collection
80+ calculators across every major clinical domain: cardiovascular (QRISK3, CHA₂DS₂-VASc, HAS-BLED, HEART, TIMI, GRACE, Framingham, SCORE2), respiratory (CURB-65, PSI/PORT, CAT, mMRC), gastroenterology and hepatology (FIB-4, NAFLD Fibrosis Score, Child-Pugh, MELD, MELD-Na, Maddrey, Lille, Glasgow-Blatchford, Rockall), neurology (NIHSS, ABCD2, Hunt and Hess, Fisher), renal (CKD-EPI, Cockcroft-Gault, KDIGO AKI staging), endocrine (corrected calcium, insulin dose adjustments), haematology (Wells DVT, Wells PE, PERC, YEARS, sPESI, Geneva, HIT score, Caprini, Padua, IMPROVE), mental health (PHQ-9, GAD-7, AUDIT-C, C-SSRS, Edinburgh Postnatal Depression Scale), surgical (APACHE II, Ranson, Alvarado, Rockall), and more.
Every tool includes the calculation, interpretation bands with clinical guidance, clinical pearls, safety caveats (when not to use the score), source references with PubMed links, and cross-links to related calculators in the clinical workflow.
Start Using iatroX Calculators
iatrox.com/calculators — 80+ clinical calculators, semantic search, UK-contextualised guidance, clinical pearls, no ads. Free. Built for UK clinicians by a practising NHS GP.