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QuickMedCalc helps you find and use 89 free medical calculators across 10 clinical areas, including kidney function, cardiovascular risk, critical-care scores, body metrics, fluids, and laboratory calculations. When similar tools overlap, compare their task, inputs, returned measure, and limitations before opening one. Results are reference aids, not diagnoses or treatment instructions.

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Featured calculators

6 featured

Featured calculatorAdult eGFR CalculatorEstimate adult race-free indexed glomerular filtration rate (eGFR) with 2021 CKD-EPI creatinine, 2012 cystatin C, or 2021 combined equations.Nephrology Featured calculatorMean Arterial Pressure (MAP) CalculatorEstimate conventional mean arterial pressure from one systolic and diastolic blood-pressure reading using the one-third pulse-pressure formula.Cardiology Featured calculatorAdult BMI Calculator (Body Mass Index)Calculate adult BMI from metric or US customary inputs, view the CDC adult screening category, and see the formula-derived weight span for BMI 18.5–24.9 at the entered height with non-diagnostic interpretation limits.General Medicine Featured calculatorAHA PREVENT-ASCVD Risk CalculatorEstimate 10-year and age-eligible 30-year risk of a first ASCVD event with the corrected AHA PREVENT base equations.Cardiology Featured calculatorWells Score Calculator for PECalculate the weighted Wells PE pretest-probability score with two-level and three-level classifications.Emergency Medicine & Critical Care Featured calculatorQTc Calculator – Bazett, Fridericia, Framingham & HodgesCompare four fixed heart-rate correction formulas from a measured QT interval and representative heart rate, with ECG measurement and interpretation limits.Cardiology

Sources & review process89 calculators · 10 clinical areas · No sign-in required

Choose by task, not just by calculator name

When similar tools use different measurements or return different estimates, compare the task, inputs, returned measure, and key distinction before opening a calculator. This is tool-selection context, not a diagnosis or treatment recommendation.

General Medicine Calculators

Body size and reference weight

Full comparison guide

These measures use related body measurements but answer different sizing or composition questions.

Adult BMI Calculator (Body Mass Index)

Use when: Screen an adult height-and-weight body-size index.
Inputs: Height and weight in supported metric or US units.
Returns: A BMI value with the page's unit and interpretation context.
Distinction: BMI is an index, not a body-surface-area or dosing-weight selection.

Body Surface Area (BSA) Calculator

Use when: Estimate body surface area for a formula that explicitly calls for BSA.
Inputs: Height and weight for the selected Mosteller, Du Bois, or Haycock equation.
Returns: Body surface area in m².
Distinction: BSA is a surface-area estimate rather than a reference weight or body-composition estimate.

Devine Ideal Body Weight Calculator for Adults

Use when: Calculate the adult Devine formula reference weight from height and sex branch.
Inputs: Adult height and the formula's sex coefficient.
Returns: Formula-specific ideal body weight in kg and lb.
Distinction: This is a historical reference-weight formula, not an automatic dosing choice.

Adult Adjusted Body Weight Calculator (AjBW 0.4)

Use when: Apply the fixed AjBW40 arithmetic when it is required and you deliberately supply an existing IBW or choose the page's local Devine IBW path.
Inputs: Total body weight plus either an externally determined ideal body weight or Devine height and published sex-coefficient inputs.
Returns: An AjBW40 result with the chosen IBW source and audit context.
Distinction: The page does not decide whether adjusted body weight is clinically appropriate, automatically select a dosing weight, or create a medication dose.

Nephrology Calculators

Kidney-function estimates

Full comparison guide

These kidney-function estimates differ in biomarker inputs, indexing, weight use, and model purpose.

Adult eGFR Calculator

Use when: Estimate indexed GFR with the selected adult CKD-EPI creatinine, cystatin-C, or combined model.
Inputs: Supported serum biomarkers, age, and sex inputs.
Returns: An indexed eGFR estimate in mL/min/1.73 m².
Distinction: eGFR is indexed and model-specific; it is not Cockcroft–Gault clearance or dialysis adequacy.

Cockcroft–Gault Creatinine Clearance Calculator

Use when: Calculate the historical adult Cockcroft–Gault creatinine-clearance estimate when that metric is required.
Inputs: Serum creatinine, age, sex branch, and an explicitly supplied weight basis.
Returns: Estimated creatinine clearance in mL/min.
Distinction: The page does not automatically select a weight or produce a medication dose.

Cardiology Calculators

Long-term cardiovascular risk

Full comparison guide

Compare model identity before comparing percentages: population, endpoint, and horizon are part of the result's meaning.

AHA PREVENT-ASCVD Risk Calculator

Use when: Estimate the AHA PREVENT-ASCVD model output for its supported primary-prevention population.
Inputs: Model population, sex coefficient, age, total cholesterol, HDL-C, systolic blood pressure, eGFR, BP treatment, statin use, diabetes, and current smoking.
Returns: PREVENT-ASCVD 10-year and, where supported by age, 30-year risk estimates.
Distinction: This is a current model-specific estimate and is not a Framingham endpoint or treatment threshold.

Framingham General CVD Risk Calculator

Use when: Calculate the historical lipid-based Framingham General CVD model for adults 30–74 without established CVD at baseline.
Inputs: Age, sex branch, lipids, systolic pressure, treatment, smoking, and diabetes inputs.
Returns: A 10-year general-CVD model percentage.
Distinction: It is a historical model-specific estimate and is not ASCVD-only or a current statin decision.

Pulmonology Calculators

Gas exchange and oxygenation

Full comparison guide

These calculations use overlapping oxygen variables but are not interchangeable; select by the measurements and support context available.

Alveolar–Arterial Oxygen Gradient (A–a) Calculator

Use when: Calculate the alveolar–arterial oxygen difference when arterial gas and alveolar-gas assumptions are available.
Inputs: PaO₂, PaCO₂, FiO₂, barometric pressure, respiratory quotient, and the page's context confirmations.
Returns: A–a oxygen gradient in mmHg.
Distinction: It compares estimated alveolar and measured arterial oxygen and does not diagnose a cause.

Complete Alveolar Gas Equation Calculator

Use when: Calculate PAO₂ with the complete alveolar gas equation or its explicitly labeled approximation.
Inputs: FiO₂, barometric pressure, PaCO₂, respiratory quotient, and the stated inspired-gas assumptions.
Returns: Estimated alveolar oxygen pressure, with audit values.
Distinction: PAO₂ is an equation output, not measured arterial PaO₂ or an oxygenation severity label.

P/F Ratio Calculator (PaO₂/FiO₂)

Use when: Calculate arterial PaO₂ relative to FiO₂ when paired arterial oxygen and FiO₂ are available.
Inputs: Arterial PaO₂ and FiO₂ with explicit units and source context.
Returns: The P/F oxygenation ratio.
Distinction: It is a ratio whose interpretation depends on support, position, time, and definition context.

Oxygenation Index (OI) Calculator

Use when: Calculate conventional OI during the supported invasive-ventilation state.
Inputs: Matched FiO₂, ventilator mean airway pressure, and arterial PaO₂.
Returns: Oxygenation Index.
Distinction: OI uses ventilator MAP and is distinct from P/F, OSI, and arterial blood-pressure MAP.

Emergency Medicine & Critical Care Calculators

Pneumonia severity

Full comparison guide

Both tools require an established adult community-acquired pneumonia context, but their item sets and class systems differ.

CURB-65 Score

Use when: Calculate the five-item CURB-65 score for adults with clinically diagnosed community-acquired pneumonia.
Inputs: Confusion, urea/BUN, respiratory rate, blood pressure, and age.
Returns: A CURB-65 point total.
Distinction: It is not interchangeable with PSI/PORT and does not prescribe disposition or treatment.

Adult Pneumonia Severity Index (PSI / PORT) Calculator

Use when: Calculate the formal Fine PSI/PORT class for established adult community-acquired pneumonia.
Inputs: The complete demographic, comorbidity, examination, laboratory, and radiographic items.
Returns: A PSI class and point total.
Distinction: PSI has a different item structure and population context from CURB-65.

Browse by clinical category

Choose a clinical area to browse its focused calculator collection, or open the full directory to search across every tool.

General Medicine Calculators20 calculatorsCommon medical math tools used across specialties, including BMI, body-shape indices, serum protein ratios, estimated fat-free mass, blood volume, fluids, and lab arithmetic.Nephrology Calculators14 calculatorsNephrology calculators for kidney-function estimation, acid-base arithmetic, fractional excretion, fluid and electrolyte estimates, urine protein assessment, and dialysis adequacy.Cardiology Calculators12 calculatorsCardiology calculators for cardiovascular risk estimation, lipid arithmetic, rhythm-related intervals, acute coronary syndrome risk, and hemodynamic measures.Pulmonology Calculators5 calculatorsPulmonology calculators for ventilated-patient oxygenation, smoking exposure, alveolar oxygen pressure, and A-a gradient assessment.Gastroenterology & Hepatology Calculators5 calculatorsGastroenterology and hepatology calculators for liver disease scores and laboratory reference arithmetic, including MELD/MELD-Na, Child-Pugh, APRI, SAAG, and the De Ritis ratio.Emergency Medicine & Critical Care Calculators13 calculatorsEmergency and critical-care calculators for acute disease-specific assessment, organ dysfunction, sepsis and systemic response, neurologic and sedation assessment, hemodynamics, burns, and resuscitation support.Neurology Calculators3 calculatorsNeurology calculators for structured stroke-deficit scoring with NIHSS, historical post-TIA risk-factor scoring with ABCD², and aneurysmal subarachnoid hemorrhage grading with Hunt-Hess.Endocrinology Calculators3 calculatorsEndocrinology calculators for glycemic indices and thyroid-function assessment, with formula notes, assay context, and interpretation limits.Pediatrics Calculators3 calculatorsPediatrics calculators for age-based weight estimation, selected medication arithmetic, and Clinical Dehydration Scale / dehydration assessment.Hematology Calculators11 calculatorsHematology calculators for derived absolute leukocyte counts and laboratory reference measures, including AMC, AEC, ANC, RPI, TSAT, NLR, PLR, LMR, and SII.

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Transparent methods

Formulas and relevant unit handling remain visible where applicable.

Source trail

Methods link to applicable original publications, professional guidelines, official standards, or other authoritative sources.

Known limits

Population, method, interpretation, and important use limitations are documented where applicable.

Evidence and review

Medical formulas, scoring rules, thresholds, intended populations, limitations, and explanatory claims are based on cited official guidance, original publications, regulatory materials, and other authoritative sources as applicable. Source scope, implementation checks, limitations, and correction routes are documented alongside the applicable tool.

QuickMedCalc is developed and maintained by an independent developer. Medical content is not independently reviewed by a physician.

Sources & review process About QuickMedCalc

Use results in context

A numeric result cannot diagnose a condition or automatically select medication, dose, treatment, or referral. Use it alongside history, examination, laboratory trends, imaging, applicable guidelines, and professional judgment. Some formulas only apply to defined populations or clinical states. In an emergency, do not rely on this website for self-management.

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