Adult Clinical Calculators
Adult clinical calculators, with the evidence shown
Fast, transparent calculators that show their formula and references — built for learning and quick reference.
Safety note. For education and reference only — not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and not stored.
Body Mass Index (BMI)
BMI = weight (kg) ÷ height (m)². A screening measure only; it does not distinguish muscle from fat.
Reference: WHO BMI classification (adults). Last reviewed June 2026.
Calculator library
More calculators
Additional adult calculators with full formula, evidence and worked examples are being added. Tell us which you need most.
What these calculators do
Scores and conversions, with the working on show
Clinical calculators turn well-established formulas and validated scoring systems into quick, repeatable computations. Used well, they reduce arithmetic slips and help you reason about a result rather than simply produce one. Our adult set spans cardiovascular risk and anticoagulation scores such as CHA₂DS₂-VASc and HAS-BLED, acute-illness and sepsis tools including NEWS2, qSOFA and CURB-65, neurological assessment with the Glasgow Coma Scale, and physiology and renal measures like mean arterial pressure and creatinine clearance. Each one states the formula it uses and the evidence behind it, so the number is never a black box.
The BMI tool above is a fully worked example of how every calculator here behaves: you enter the inputs, the result and its interpretation appear instantly, and the calculation runs in your browser without sending or storing your data. BMI itself is a screening measure — it cannot distinguish muscle from fat or describe fat distribution — which is exactly the kind of limitation we surface rather than hide.
Getting a reliable result
Using a calculator well
- Check the unitsEnter values in the units the form asks for — kilograms, centimetres, mmol/L — as a unit mismatch is the commonest source of error.
- Read the interpretationThe score is only the start; the category or threshold the calculator returns is what guides judgement.
- Confirm the contextA validated score assumes a defined population. Make sure your patient fits it before applying the result.
- Verify before actingCross-check against local guidance and the BNF, and treat the calculator as a prompt to think, not a decision in itself.
How this page sits among our other tools
For weight-based dosing and fluids in children, use the dedicated paediatric calculators, which carry additional safety cautions. When a score points you towards a medicine, look it up in the Medicine Finder and review its profile in the Drug Safety & Side-Effect Checker. The full computed set lives in the calculator library.
Revising these scores for an exam? Pair them with a structured plan from the Exam Revision Planner.
Answers
Frequently asked questions
Are these calculators safe to use clinically?
They are for education and reference only and are not a substitute for clinical judgement, local policy or product labelling. Always independently verify any result, and check local guidance, before clinical use.
Where do the formulas come from?
Each calculator states its formula, evidence basis and references. Results are computed in your browser; we do not store the values you enter.
Who reviews these tools?
Our Clinical Director reviews calculator logic and references, and each tool carries a last-reviewed date. See our Quality & Editorial Policy.
Which validated scores are covered?
The adult set includes CHA₂DS₂-VASc, HAS-BLED, CURB-65, qSOFA, NEWS2, the Glasgow Coma Scale, Wells (DVT), Cockcroft-Gault creatinine clearance, mean arterial pressure, corrected calcium, anion gap and BMI, with more being added. The complete computed set is in our calculator library.
Do I need a paediatric tool for a child?
Yes. Adult formulas do not transfer safely to children, where dosing and fluids are weight-based and higher-risk. Use the paediatric calculators, which carry their own safety cautions.
Need a specific calculator or a custom tool?
We build evidence-led calculators and reference tools for teams.