Creatinine Clearance Calculator
Tip: commas are allowed (e.g. 1,000).
Educational use only. Always follow local policy for dosing and verify calculations in clinical context.
Written by George Lambroglou, RN • Formula checked against listed references • Last reviewed 21 Jun 2026
Estimate creatinine clearance (CrCl) with the Cockcroft-Gault equation for medication dosing support. Enter serum creatinine in either Australian-style µmol/L or mg/dL.
Cockcroft-Gault formula
CrCl = ((140 − age) × weight × sex factor) ÷ (72 × serum creatinine in mg/dL)
CrCl = ((140 − age) × weight × sex factor) ÷ (0.814 × serum creatinine in µmol/L)
The calculator uses the SI-unit version internally when creatinine is entered in µmol/L, and converts mg/dL to µmol/L when needed. The result is shown in mL/min.
Worked examples
Example 1: µmol/L result
70-year-old male, 80 kg, serum creatinine 120 µmol/L: ((140 − 70) × 80 × 1.0) ÷ (0.814 × 120) = 57.3 mL/min.
Example 2: mg/dL result
65-year-old female, 70 kg, serum creatinine 1.2 mg/dL: ((140 − 65) × 70 × 0.85) ÷ (72 × 1.2) = 51.6 mL/min.
Frequently asked questions
Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.
Related calculators
References
Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31–41.
RCPA Manual. Creatinine clearance estimated: eGFR. Includes Cockcroft-Gault equation with serum creatinine in µmol/L.
eviQ. Creatinine Clearance Calculator. Includes Cockcroft-Gault estimates using actual, ideal, and adjusted body weight contexts.
BNF/NICE. Prescribing in renal impairment. Recommends estimating creatinine clearance for many medicine dosing decisions.