Creatinine Clearance (CrCl)
Estimate renal function with the Cockcroft-Gault equation to guide renally-cleared drug dosing.
Creatinine Clearance estimates how well a patient's kidneys are filtering — the single most common check before dosing a renally-cleared drug. See How Calculator Tools Work for the shared layout.
Inputs
- Age (1–120 years)
- Weight (kg)
- Sex (male/female)
- Serum creatinine, with a unit toggle between mg/dL and μmol/L
The formula
CrCl uses the Cockcroft-Gault equation:
CrCl = ((140 − age) × weight) / (72 × serum creatinine)...multiplied by 0.85 if the patient is female. If you entered creatinine in μmol/L, it's converted to mg/dL first (÷ 88.4) before the calculation runs.
Reading the result
| CrCl (mL/min) | Classification | Dose adjustment |
|---|---|---|
| ≥ 90 | Normal | Not required |
| 60–89 | Mild impairment | Not required |
| 30–59 | Moderate impairment | Recommended |
| 15–29 | Severe impairment | Recommended |
| < 15 | End-stage renal disease | Recommended — consider nephrology referral |
If the result needs dose adjustment, a "View dose adjustments" link takes you straight to Renal Dose Adjustment with the value carried over.
Results above 180 mL/min are capped at 180 with a warning — a value that high usually means hyperfiltration or a data-entry error, not genuinely elevated renal function.
Warnings you might see
- Elderly patient with low creatinine (age > 65, creatinine < 0.8 mg/dL): low creatinine can reflect reduced muscle mass rather than good renal function in older patients, so Cockcroft-Gault may overestimate true GFR — the tool suggests considering the CKD-EPI equation for a more accurate picture in this group.
References
Cockcroft DW, Gault MH. Nephron. 1976;16(1):31-41.