Clinical tools

General Medicine Calculators

General Medicine brings together common calculation tasks for body size, reference weight, body composition, laboratory and specimen arithmetic, fluid estimates, infusion arithmetic, and unit conversion. Start with the measurements and question you have, then choose the calculator whose formula, units, and stated scope match.

Tools by task

Anthropometry and reference weight

Use one measurement workspace for adult size, surface-area, composition, waist, hip, and body-shape models; use the separate Devine/AjBW40 workflow for historical reference-weight arithmetic.

Adult Anthropometry WorkspaceCalculate adult body surface area (BSA) with an explicitly selected Mosteller, Du Bois, or Haycock formula and BMI from height and weight; add optional measurements for other named anthropometry models.IBW & AjBW40Ideal Body Weight (IBW) & Adjusted Body Weight CalculatorCalculate adult ideal body weight (IBW) with the Devine formula from height and optionally derive fixed adjusted body weight (AjBW40) from actual weight.Estimated Blood Volume Calculator (Adult Nadler & Lemmens)Estimate reference blood volume with the adult Nadler or Lemmens formula, or perform arithmetic using an explicitly supplied external mL/kg protocol coefficient.

Laboratory and specimen arithmetic

Match units, collection timing, and specimen identity before calculating a laboratory difference, ratio, or conventional adjustment.

Corrected Calcium Calculator (Albumin-Adjusted)This calculator reproduces the conventional 0.8 albumin-adjusted calcium formula from measured total calcium and albumin. Current 2026 laboratory-medicine guidance recommends against routine reporting; the result is not measured ionized calcium.Anion Gap Calculator – Formula & Albumin CorrectionCalculate the serum anion gap without potassium from sodium, chloride, and bicarbonate/total CO₂, with an optional separate Figge 2.5 albumin adjustment.Stool Osmotic Gap CalculatorEstimate stool osmotic gap from stool sodium and potassium using the conventional assumed 290 mOsm/kg model, with collection and interpretation limits.A/G RatioAlbumin/Globulin (A/G) Ratio CalculatorCalculate A/G ratio from albumin with reported globulin or same-panel total protein; total-protein mode also shows calculated globulin with laboratory-specific interpretation limits.

Fluids, infusion, and unit conversion

Separate maintenance-fluid estimation from gravity drip-rate arithmetic and unit conversion; each tool requires different inputs and answers a different question.

Maintenance FluidsMaintenance Fluid Calculator (Pediatric & Adult)Calculate pediatric 4-2-1 and Holliday–Segar 100/50/20 maintenance fluid estimates, with a separate adult NICE routine-maintenance pathway.IV Drip Rate Calculator (gtt/min & mL/hr)Calculate whole-drop gravity IV rate and mathematical flow rate from volume, time, and tubing drop factor.Medical Lab Unit Converter – mg/dL, mmol/L & µmol/LConvert 11 common serum and plasma laboratory values between conventional and SI reporting units using analyte-specific factors.

Important limits

Formula-derived body measures are estimates and do not replace direct measurement or a complete nutritional or clinical assessment.
Laboratory differences and ratios cannot establish a diagnosis without assay, specimen, trend, and clinical context.
These calculators do not prescribe a fluid, infusion, medication, or patient-specific treatment.

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