General Medicine Calculators

Calculates BMI from weight and height. WHO obesity classification.

Calculates BSA using Mosteller formula. Used for chemotherapy dosing and cardiac index.

Estimates ideal body weight using Devine formula. Used for drug dosing and ventilator settings.

Calculates adjusted body weight for obese patients: IBW + 0.4×(Actual - IBW).

Calculates serum osmolality. Osmol gap = Measured − Calculated (>10 suggests toxic alcohol ingestion).

Assesses VTE risk in medical inpatients to guide pharmacological thromboprophylaxis.

Malnutrition Universal Screening Tool. Identifies patients at risk of malnutrition.

Predicts 10-year mortality based on comorbid conditions. Widely used for risk adjustment in research and clinical decision-making.

Rockwood Clinical Frailty Scale — 9-point clinical judgment tool for frailty. Predicts adverse outcomes and guides treatment decisions.

Rapid bedside screening tool for delirium and cognitive impairment. Does not require special training.

Six-factor pressure ulcer risk assessment. Scores range from 6 (highest risk) to 23 (lowest risk).

Calculates LDL from total cholesterol, HDL, and triglycerides. LDL = TC − HDL − (TG / 2.2). Not valid if TG >4.5 mmol/L.

Six-item validated tool for identifying patients at risk of falls in hospital settings.

Functional mobility test: time taken to rise from chair, walk 3 metres, return and sit. Predicts fall risk and functional independence.

Predicts 30-day potentially avoidable hospital readmissions using seven variables available at discharge.

Predicts 30-day unplanned readmission or death after hospital discharge using Length of stay, Acuity, Comorbidity, and Emergency visits.

Standardised diagnostic algorithm for delirium detection. Requires features 1+2 PLUS either 3 or 4 for positive diagnosis.

Assesses risk of pressure ulcer development. Higher scores indicate higher risk.

Assesses functional exercise capacity. Calculates predicted 6MWT distance and interprets measured distance as percentage predicted.

30-point questionnaire assessing orientation, registration, attention, recall, and language. Standard cognitive screening tool.

30-point cognitive screening tool more sensitive than MMSE for mild cognitive impairment (MCI). Assesses 8 cognitive domains.

Functional Assessment Staging Test (FAST) — tracks functional decline in Alzheimer's disease from normal to severe. Used in care planning and prognostication.

Measures functional status and prognosis in palliative care patients. Modified Karnofsky scale adapted for end-of-life care. Score 10–100% in 10% increments.

Detailed 17-condition comorbidity index predicting 10-year mortality. Age-adjusted version adds 1 point per decade after age 50.

Calculates NNT or NNH from event rates in treatment and control groups. Fundamental EBM tool for communicating treatment effectiveness.

Calculates sensitivity, specificity, PPV, and NPV from a 2x2 contingency table. Essential for evaluating diagnostic tests.

Converts pre-test probability to post-test probability using positive or negative likelihood ratios. Key tool for Bayesian clinical reasoning.

Measures comorbidity burden using 31 weighted conditions. Predicts in-hospital mortality, length of stay, and resource utilisation.

Predicts 30-day survival probability in advanced cancer patients using dyspnoea, anorexia, Karnofsky Performance Status, WBC, lymphocyte percentage, and clinician estimate.

Guides structured assessment of CPR appropriateness using clinical, ethical, and patient-centred domains. Supports DNACPR and ReSPECT documentation.

Calculates LDL cholesterol using the Friedewald equation when direct LDL not available. LDL = Total Cholesterol − HDL − (Triglycerides ÷ 2.2) in mmol/L. Valid only when triglycerides <4.5 mmol/L. Inaccurate in hypertriglyceridaemia, type III hyperlipidaemia, or non-fasting samples.

Simple inflammatory index calculated from FBC. Elevated NLR (>3.5–5) indicates systemic inflammation, infection, or stress. Useful prognostic marker in sepsis, cancer, cardiovascular disease, and COVID-19. Low NLR (<1) may suggest immunosuppression or viral illness.

Converts equivalent doses between benzodiazepines based on diazepam equivalency. Used for cross-tapering, dose reduction, and management of benzodiazepine dependence. All values expressed as diazepam 5 mg equivalents. Note: equivalencies are approximate and require clinical judgement.

6-item clinical prediction rule for diagnosing carpal tunnel syndrome (CTS) without the need for nerve conduction studies (NCS). Items: nocturnal symptoms, hand diagram, wrist ratio index, Phalen's test, loss of 2-point discrimination, weakness/atrophy. Score ≥12 = high likelihood CTS.

Simple, validated bedside test for detecting hypoxaemia without pulse oximetry. Patient counts aloud from 1 as fast as possible on a single breath. Count-to-20 test: counts ≥20 AND breath-holding time ≥10 seconds effectively rules out SpO₂ <95%. Useful in resource-limited settings.

Pre-test probability score for deep vein thrombosis (DVT). Guides D-dimer and Doppler ultrasound ordering.

Predicts Group A streptococcal (GAS) pharyngitis to guide throat swab and antibiotic prescribing decisions.

Assesses VTE risk in surgical patients. Guides mechanical and pharmacological prophylaxis decisions.

Estimates annual stroke risk in non-valvular AF. Guides anticoagulation decision (OAC vs no treatment) per ESC/NICE guidelines.

Predicts 30-day mortality in alcoholic hepatitis. MDF >= 32 indicates severe disease where corticosteroids may be beneficial.

Assesses response to corticosteroids at day 7 in severe alcoholic hepatitis (MDF >= 32). Lille score >= 0.45 = non-response; stop steroids.

Systematically identifies the cause of hyponatraemia using plasma osmolality, urine osmolality, and urine sodium. Guides targeted treatment.

Grades hyperkalaemia severity and guides sequential management from ECG stabilisation to potassium excretion per Renal Association/NICE guidelines.

Standard radiological response criteria for solid tumour clinical trials and routine oncology (Eisenhauer 2009). Assesses change in sum of longest diameters (SLD) of up to 5 target lesions vs baseline, and new lesions or unequivocal progression of non-target lesions.

Validated prognostic score for operable breast cancer (Haybittle 1982; revised). NPI = (0.2 × tumour size in cm) + nodal stage + tumour grade. Pick the band closest to your calculated value.

PREDICT v3 (2024) is a Cambridge online tool estimating absolute benefit of adjuvant chemotherapy / endocrine / trastuzumab / bisphosphonates / chemo+olaparib (BRCA) in early breast cancer. This calc lets you record the calculated 10-year overall survival band and treatment recommendation summary. Always run the live tool at predict.nhs.uk for individualised numbers.

International Metastatic RCC Database Consortium criteria for systemic-therapy-treated mRCC (Heng 2009). Sums 6 adverse factors. Predicts overall survival on first-line therapy and stratifies for combination therapy decisions.

8-item screening tool for older adults with cancer (Bellera 2012; SIOG endorsed). Score ≤14/17 indicates need for full comprehensive geriatric assessment (CGA) before treatment decisions.

Stratifies risk of severe chemotherapy toxicity in adults ≥70 (Extermann 2012). Combines patient factors (haemoglobin, creatinine clearance, IADL, MMSE/MNA, ECOG, LDH) + chemotherapy regimen toxicity. Use the band closest to your calculated score.

11-item predictive tool for grade 3+ chemotherapy toxicity in adults ≥65 with cancer (Hurria 2011, validated 2016). Age, tumour, regimen factors, lab values and geriatric assessment items. Score 0–19. Use the band closest to your calculated total.