Medical Calculators
Absolute Neutrophil Count Calculator
Calculate Absolute Neutrophil Count (ANC) from total WBC count and differential percentages to assess infection risk.
Anion Gap Calculator
Calculate the anion gap from sodium, chloride, and bicarbonate to help classify the cause of metabolic acidosis.
BMI Percentile Calculator
Work out BMI from height and weight and see how paediatric BMI-for-age percentile bands are defined, with the standard categories explained in full.
Body Surface Area (BSA) Calculator
Calculate body surface area with the Mosteller formula, plus a computed BSA reference grid across heights from 150 to 190 cm and weights to 100 kg.
CHA₂DS₂-VASc Calculator
Work through the CHA2DS2-VASc point scheme letter by letter, with the published annual stroke risk figures from the Friberg registry validation cohort.
Corrected Age Calculator
Adjust a premature baby's chronological age for weeks of missed gestation, with the prematurity adjustment table and a worked developmental example.
Corrected Calcium Calculator
Calculate albumin-corrected total calcium to account for how low albumin levels can make measured calcium appear falsely low.
Creatinine Clearance Calculator
Estimate creatinine clearance with Cockcroft-Gault, including a computed reference table by age, sex and creatinine, and how it differs from eGFR.
eGFR Calculator
Estimate GFR using the race-free CKD-EPI 2021 creatinine equation, with a computed reference table across age, sex and creatinine plus KDIGO categories.
Fractional Excretion of Sodium Calculator
Calculate Fractional Excretion of Sodium (FENa) to help distinguish prerenal from intrinsic renal causes of acute kidney injury.
Glasgow Coma Scale Calculator
Calculate the total Glasgow Coma Scale (GCS) score from eye, verbal, and motor response component scores.
Heart Attack Risk Calculator
An educational point tally of six cardiovascular risk factors - age, sex, cholesterol, blood pressure, smoking and diabetes - with every weighting shown.
Mean Arterial Pressure Calculator
Calculate Mean Arterial Pressure (MAP) from systolic and diastolic blood pressure readings.
Medication Dosage Calculator
Multiply a mg/kg rate by body weight, with a computed dose reference grid and a breakdown of where weight-based dosing errors actually come from.
MELD Score Calculator
Compute the original 2002 MELD score from bilirubin, INR and creatinine, with worked examples and an explanation of the floor, cap and dialysis rules.
Pack-Years Calculator
Calculate pack-years of smoking history from cigarettes per day and years smoked, used in screening and risk assessment.
Pediatric Dosage Calculator
Apply Clark's Rule to scale an adult dose by a child's weight, with a computed dose table and a clear account of why the rule has been superseded.
Pediatric Maintenance Fluid Calculator
Calculate pediatric maintenance IV fluid rate from body weight using the standard Holliday-Segar 4-2-1 method.
QTc Calculator
Calculate the heart-rate-corrected QT interval (QTc) from measured QT and RR intervals using Bazett's formula.
Wells Score Calculator
Score the nine Wells criteria for DVT, including the one criterion that subtracts two points, and see how the low, moderate and high bands are drawn.
Clinical Numbers That Guide Real Decisions
Clinical calculators translate a patient's lab values and vitals into standardized scores that doctors use to guide treatment decisions — scores built from validated formulas, not rules of thumb. These eleven calculators cover commonly used clinical reference tools.
Kidney Function Staging by eGFR
| Stage | eGFR (mL/min/1.73m²) | Description |
|---|---|---|
| G1 | 90 or above | Normal kidney function |
| G3a | 45 - 59 | Mild to moderate reduction |
| G5 | Below 15 | Kidney failure |
This staging system is exactly why eGFR is tracked as a trend over time rather than judged from one reading — a stable G2 and a rapidly declining G2 headed toward G3 represent very different clinical pictures despite an identical single-visit number. Calculate eGFR with the eGFR Calculator.
Popular Medical Calculators
- Body Surface Area (BSA) Calculator — calculates BSA from height and weight, used for medication dosing.
- Wells Score Calculator — estimates clinical probability of deep vein thrombosis from risk factors.
- Pediatric Dosage Calculator — calculates weight-based medication dosing for pediatric patients.
Related: Health Calculators for general wellness tools, Dental Calculators.