Skip to main content

DigitalCalculators.net

Menu

Creatinine Clearance Calculator

Estimate creatinine clearance (CrCl) with the Cockcroft-Gault equation from age, sex, weight, height and serum creatinine, using actual, ideal and adjusted body weight.

Results

ItemValue
For information only, not medical advice. Cockcroft-Gault was built for adults with stable kidney function and is not reliable in acute kidney injury, pregnancy, very low muscle mass or amputation. Drug dosing decisions belong to a doctor or pharmacist.

Quick Answer

Creatinine clearance = (140 − age) × weight in kg ÷ (72 × serum creatinine in mg/dL), times 0.85 for women. A 60-year-old man weighing 80 kg with a creatinine of 1.0 mg/dL has (80 × 80) ÷ 72 = 88.9 mL/min with actual weight, or 78.3 mL/min with his ideal weight of 70.5 kg.

Last updated: 10 November 2026 ·How we calculate this: the Cockcroft-Gault equation (1976)

How This Creatinine Clearance Calculator Works

Creatinine clearance (CrCl) estimates how much blood the kidneys clean of creatinine each minute. Doctors and pharmacists still use the Cockcroft-Gault estimate of CrCl to adjust doses of many medicines. Enter age, sex, weight, height and the serum creatinine from a blood test. The calculator gives CrCl with actual, ideal and adjusted body weight, and highlights the weight most often used for the patient’s size.

Quick explanation: higher creatinine and older age mean lower clearance.

  • About 90 to 140 mL/min is typical for healthy young adults.
  • Below 60 mL/min often means reduced kidney function.
  • Below 30 mL/min usually needs dose changes for many drugs.

How to Use the Creatinine Clearance Calculator

  1. Choose metric or US units and the sex.
  2. Enter age, weight and height.
  3. Enter the serum creatinine and choose mg/dL or µmol/L.
  4. Press Calculate.
  5. Read the suggested CrCl and the values with each body weight.

Cockcroft-Gault Equation

  • Men: CrCl = (140 − age) × weight (kg) ÷ (72 × serum creatinine in mg/dL)
  • Women: the same result × 0.85
  • Ideal body weight (Devine): 50 kg for men or 45.5 kg for women + 2.3 kg per inch over 5 feet
  • Adjusted body weight: ideal + 0.4 × (actual − ideal)
  • Units: creatinine in µmol/L ÷ 88.4 = mg/dL; 1 lb = 0.4536 kg; 1 in = 2.54 cm

Which weight to use differs between hospitals. A common rule, used here for the highlighted result, is actual weight if it is below ideal weight, adjusted weight if actual weight is more than 130% of ideal, and ideal weight otherwise.

Key Terms

  • Creatinine: a waste product made by muscles and removed by the kidneys.
  • Creatinine clearance: the volume of blood cleared of creatinine per minute, in mL/min.
  • Ideal body weight: an estimate of lean weight from height and sex (Devine formula).
  • Adjusted body weight: ideal weight plus 40% of the extra weight above it.
  • eGFR: estimated glomerular filtration rate, standardized to 1.73 m² of body surface.

Worked Example

A 72-year-old woman weighs 140 lb, is 5 ft 4 in tall and has a serum creatinine of 1.3 mg/dL.

  • Weight = 140 × 0.4536 = 63.5 kg; ideal weight = 45.5 + 2.3 × 4 = 54.7 kg
  • Actual weight is 116% of ideal, so ideal weight is used
  • CrCl = (140 − 72) × 54.7 ÷ (72 × 1.3) × 0.85 = 33.8 mL/min
  • With actual weight it would be 39.2 mL/min

Real-Life Examples

  • Drug dosing checks: many antibiotics and blood thinners list doses by CrCl bands such as 30 to 50 mL/min.
  • Older adults: a 72-year-old woman with a creatinine of 1.3 mg/dL has a CrCl of about 34 mL/min.
  • Obesity: a 45-year-old man weighing 120 kg at 180 cm with 106 µmol/L creatinine has 132 mL/min with actual weight but 102 mL/min with adjusted weight.
  • Study: see how age, weight and creatinine each change the estimate.

Creatinine Clearance vs eGFR

  • CrCl (Cockcroft-Gault) gives mL/min for the person’s own body size and uses weight. It is often used for drug dosing.
  • eGFR (CKD-EPI 2021) gives mL/min/1.73 m² for a standard body size and does not use weight. It is used to stage kidney disease.
  • Both are estimates from serum creatinine; a measured 24-hour urine clearance is more direct.

CrCl by Age and Creatinine (70 kg man)

Values in mL/min. Multiply by 0.85 for a woman of the same weight.

Serum creatinineAge 30Age 50Age 70Age 85
0.7 mg/dL1531259776
0.9 mg/dL119977659
1.0 mg/dL107886853
1.2 mg/dL89735745
1.5 mg/dL71584536
2.0 mg/dL53443427
3.0 mg/dL36292318

Limits of Creatinine Clearance Estimates

Creatinine comes from muscle, so the equation assumes average muscle for a person’s age, sex and weight. It overestimates kidney function in people with little muscle, such as frail older adults or people with amputations, and can underestimate it in very muscular people. Body weight from fat does not make creatinine, which is why ideal or adjusted weight is used for people with obesity.

The equation needs a steady creatinine level. In acute kidney injury, creatinine is still rising and the estimate is too high. Modern labs report eGFR from the CKD-EPI equation for staging kidney disease, while many drug labels were written using Cockcroft-Gault CrCl, so both are still in use.

Cockcroft and Gault derived the formula in 1976 from 249 men. The 0.85 factor for women was a suggested correction for lower average muscle mass, not measured directly.

Common Mistakes to Avoid

  • Mixing creatinine units. 1.0 mg/dL is 88.4 µmol/L; choose the right unit.
  • Using actual weight in obesity. It overestimates clearance; use adjusted weight.
  • Using it in acute kidney injury. The equation needs a stable creatinine.
  • Treating CrCl as eGFR. They use different units and are not interchangeable.
  • Using it for children. Cockcroft-Gault is for adults only.

Frequently Asked Questions

Roughly 90 to 140 mL/min in healthy young adults, falling with age.

Use Cockcroft-Gault: (140 − age) × weight in kg ÷ (72 × creatinine in mg/dL), times 0.85 for women.

Commonly actual weight if below ideal, adjusted weight if over 130% of ideal, and ideal weight otherwise. Follow local policy.

Women have less muscle mass on average, so they make less creatinine at the same kidney function.

No. CrCl slightly overestimates GFR because a little creatinine is secreted by the kidney tubules.

It depends on the drug. Many labels change doses below 50 or 30 mL/min; check the drug’s prescribing information.

Divide by 88.4. For example, 106 µmol/L is 1.2 mg/dL.

No. Children need pediatric equations such as the bedside Schwartz formula.

The lab uses CKD-EPI, which ignores weight and reports per 1.73 m², so the numbers differ.

References & Sources

SourceUsed ForLink
Cockcroft DW, Gault MH (1976), Prediction of creatinine clearance from serum creatinine Nephron 16(1):31-41. The equation and 0.85 factor for women. https://pubmed.ncbi.nlm.nih.gov/1244564/
MSD Manual, Creatinine Clearance Estimate by Cockcroft-Gault Equation Calculator and notes on use. https://www.msdmanuals.com/medical-calculators/CreatinineCl_CG-en.htm