GFR: the single best kidney function number
CKD-EPI 2021 is the current gold standard. It dropped the race coefficient and is used for staging chronic kidney disease worldwide.
MDRD is older but still seen in lab reports. Cockcroft-Gault gives creatinine clearance, preferred for drug dosing.
Schwartz is the paediatric formula using height and creatinine. ⚠ This tool is educational — always confirm with your clinician.