Clinical tools

Nephrology Calculators

Nephrology calculators cover kidney-function and dialysis estimates, serum electrolyte and water arithmetic, acid-base measures, urine ratios, output, and fractional excretion. Their inputs and intended uses differ even when the same analyte appears.

Keep specimen identity, collection duration, dialysis-session timing, and model-specific assumptions aligned with the selected page.

Tools by task

Kidney-function and dialysis estimates

Choose between adult CKD-EPI eGFR, historical Cockcroft–Gault creatinine clearance, and protocol-dependent hemodialysis adequacy arithmetic.

Adult eGFR CalculatorEstimate adult race-free indexed glomerular filtration rate (eGFR) with 2021 CKD-EPI creatinine or combined creatinine–cystatin C and the 2012 cystatin C equation.Creatinine Clearance (CrCl) Calculator – Cockcroft–GaultCalculate adult creatinine clearance (CrCl) with the Cockcroft–Gault equation using age, an explicit weight basis, serum creatinine, and the published sex coefficient.Kt/V Calculator – Daugirdas II spKt/V & URRCalculate adult single-pool Kt/V and URR from paired pre/post BUN or urea, delivered time, ultrafiltration, and post-dialysis weight for one completed intermittent hemodialysis treatment.

Serum electrolytes, osmolality, and water

Use measured serum inputs and the specified units for hyperglycemia-adjusted sodium, calculated osmolality, or free-water-deficit arithmetic.

Corrected Sodium Calculator for HyperglycemiaCalculate corrected sodium from measured sodium and paired glucose using Katz 1.6 and Hillier overall 2.4, with glucose in mg/dL or mmol/L.Serum Osmolality/Osmolarity CalculatorCalculate serum osmolality and effective osmolality (tonicity), with optional measured osmolality, osmolal gap, and separate ethanol assumptions; no toxic-alcohol or HHS diagnosis.Free Water Deficit Calculator (Explicit TBW Coefficient)Estimate a static positive free water deficit for hypernatremia when current sodium is >145 mmol/L or mEq/L, using an explicitly selected lower target, kg or lb weight, and an explicit TBW coefficient, with estimated TBW and results in L and mL—not an infusion volume or treatment output.

Acid-base arithmetic

Select urine anion-gap arithmetic or a bicarbonate-deficit estimate according to the required measurements and assumptions; the consolidated serum anion-gap workspace remains in General Medicine.

Urine Anion Gap Calculator (Na + K − Cl)Calculate the one-decimal signed urine anion gap from sodium, potassium, and chloride in the same urine specimen using mmol/L or mEq/L, without treating UAG as direct urine ammonium or a universal positive/negative diagnosis.Bicarbonate Deficit CalculatorCalculate an estimated positive bicarbonate deficit from measured and target bicarbonate, body weight, and an explicit distribution factor, with a canonical calculation audit and clear limits.

Urine and renal-handling measures

Match urine protein, urine output, BUN/creatinine, FENa, or FEUrea inputs to the stated collection and paired-sample requirements.

Protein Creatinine Ratio Calculator – Urine UPCR / PCRCalculate spot urine total protein divided by same-specimen creatinine in mg/g, mg/mmol, and mg/mg, with interpretation boundaries distinct from ACR and measured 24-hour protein.Measured Urine Output Rate Calculator (mL/hr & mL/kg/hr)Calculate measured urine output for one completed collection interval as average mL/hr and average mL/kg/hr using protocol-selected weight, without AKI diagnosis, stage, or treatment output.BUN/Cr RatioBUN/Creatinine Ratio CalculatorCalculate the conventional BUN/creatinine ratio from paired BUN or urea and creatinine values with US/SI unit normalization and neutral interpretation context.FENa & FEUrea CalculatorCalculate FENa from urine and serum sodium and creatinine, with an optional separate FEUrea calculation from urine and serum urea or BUN plus the same creatinine record.

Important limits

A calculated kidney-function or urine result does not by itself diagnose acute kidney injury or chronic kidney disease.
Changing biomarkers, non-steady-state creatinine, collection error, and nonrenal determinants can limit these estimates.
These pages do not generate medication doses, dialysis prescriptions, referral instructions, or treatment decisions.

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