GFR Calculator: Estimating renal function

The efficiency or function of your kidneys can be estimated by means of different formulas. All these formulas include the lab-value "serum creatinine", because the concentration of creatinine in your blood correlates inversely with your kidney function: If kidney function declines, serum creatinine rises. Thus, kidney function can be estimated from a routine measurement of creatinine in your blood.

A commonly used equation is the Cockcroft-Gault formula, which estimates creatinine clearance. This estimated creatinine clearance equates precisely with the glomerular filtration rate (GFR), which is the best measure for renal function. Another formula for estimating the GFR is the Modification of Diet in Renal Disease (MDRD) Study equation.

Please note: The GFR formulas have been developed in study populations of patients suffering from chronic kidney disease. In healthy subjects they may provide less precise estimations. Furthermore they are not valid for children.

Did you know...?

  • GFR is lower at older ages. From the age of 20 to 30 years, GFR decreases by approximately 1.0 ml/min/1.73 m2 per year with inter-individual variation even among healthy individuals.

  • Creatinine generation is proportional to the total muscle mass. Therefore, it is usually higher in men than in women, in younger than in older individuals, and in blacks than in whites.

Calculate your renal function

Please fill in decimal places with dots, for example: 1.5 mg/dl or 62.3 kg.

Stages of chronic kidney disease on the basis of GFR

Defined by the level of GFR, there are 5 stages of chronic kidney disease (according to NKF-KDOQI Guidelines [1]). Stage 1 is the earliest, while Stage 5 represents kidney failure or end-stage renal disease (ESRD), respectively.

Stages of chronic kidney disease according to NKF-KDOQI Guidelines [1]

Content last updated
  1. KDOQI Clinical Practice Guidelines for Chronic Kidney Disease: Evaluation, Classification and Stratification. Am J Kidney Dis 2002; 39 (Suppl 1): 1-222. (last visited 05.05.2010)
  2. Kuhlmann U, Walb D, Böhler J, Luft FC: Nephrologie. Thieme, 5th edition, 2008.