GFR Calculators

Use these GFR calculators to estimate kidney function for adults and children.

At this time, all laboratories should be using creatinine methods calibrated to be isotope dilution mass spectrometry (IDMS) traceable. In the US and other countries, nearly all methods from the major global manufacturers now have calibration traceable to an IDMS reference measurement procedure.¹ Consequently, the calculators for older non-standardized creatinine methods are no longer available on this web site. Learn more information about creatinine standardization.

GFR Calculator for Adults (for patients 18 and older)

In adults, the recommended equation for estimating glomerular filtration rate (GFR) from serum creatinine is the Modification of Diet in Renal Disease (MDRD) Study equation. The IDMS-traceable version of the MDRD Study equation is used.

IDMS-traceable MDRD Study Equation GFR Calculators for Adults
Conventional units » (for use primarily in the U.S.)	SI units » (for use outside of the U.S.)

GFR Calculator for Children

Currently the best equation for estimating glomerular filtration rate (GFR) from serum creatinine in children is the Bedside Schwartz equation for use with creatinine methods with calibration traceable to IDMS^{2, 3}. Using the original Schwartz equation with a creatinine value from a method with calibration traceable to IDMS will overestimate GFR. Read additional laboratory guidelines on calculating estimated GFR for children.

Bedside IDMS-traceable Schwartz GFR Calculator for Children
Conventional units » (for use primarily in the U.S.)	SI units » (for use outside of the U.S.)

Frequently Asked Questions About Estimated GFR Values

What are considered average estimated GFR (eGFR) values for adults?

The table below shows population estimates for mean (average) estimated glomerular filtration rate (eGFR) by age. These means, derived from the NHANES III survey of over 10,000 individuals, demonstrate that eGFR varies across age groups and that kidney function tends to decline with age. There is no difference between races or sexes when eGFRs are expressed per meter squared body surface area.

Reference Table for Population Mean eGFRs From NHANES III⁴

Age (Years)	Mean eGFR*
20-29	116 mL/min/1.73 m2
30-39	107 mL/min/1.73 m2
40-49	99 mL/min/1.73 m2
50-59	93 mL/min/1.73 m2
60-69	85 mL/min/1.73 m2
70+	75 mL/min/1.73 m2

*For diagnostic purposes the NKDEP recommends laboratories report eGFR values greater than or equal to 60 as "≥ 60 mL/min/1.73 m²," not as an exact number.

Can eGFRs be used in hospitalized patients?⁵

Estimated GFR derived from the MDRD Study equation can be used in patients who are in the hospital. However, it is important to pay attention to potential inaccuracies due to the non-steady state of serum creatinine, co-morbidities that cause malnutrition, and the use of medications that interfere with the measurement of serum creatinine.

For additional frequently asked questions, please visit www.kidney.org/professionals/KLS/gfr.cfm#faq.

References

1.Miller WG. Estimating glomerular filtration rate. Clin Chem Lab Med. 2009;47:1017–19.

2.Schwartz GJ, Muñoz A, Schneider MF, et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol. 2009:20(3):629–37.

3.Schwartz GJ and Work DF. Measurement and estimation of GFR in children and adolescents. J Am Soc Nephrol. 2009; Nov; 4(11): 1832–643.

4.Coresh J, Astor BC, Greene T, Eknoyan G, et al. Prevalence of chronic kidney disease and decreased kidney function in the adult US population: Third national health and nutrition examination survey. American Journal of Kidney Disease. 2003; 41 (1): 1-12.

5.Levey and Stevens, Frequently Asked Questions About GFR Estimates, copyright National Kidney Foundation, 2004.

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