Background: Glomerular Filtration Rate (GFR) will measure the filtration capacity of kidney. The estimated GFR play important role in clinical management of various diseases and altered renal function influence the use of the therapeutic agents. Serum creatinine estimation is simple and commonly used for estimation of GFR. These methods are simple, cost effective and required less time. Methods:The study comprised of 175 subjects, of these Children group comprised of 75 healthy childrens The adult and old age people comprised of 100 healthy individuals. In all the participants Serum creatinine are blood urea are estimated. In childrens eGFR was estimated by using Schwartz equations and Counahan-Barrad formula. In adult and old age people the eGFR was estimated by Cockcroft-Gault formula (CG) and Modification of Diet in Renal Disease (MDRD) and Mayo Clinic Quadratic Equation (MCQE). Results: Schwartz equation given a significantly (p< 0.001) higher GFR values in childrens when compared with Counahan-Barrad. Counahan-Barrad formulae included normal healthy childrens in to GFR ≤ 90 mL/min/1.73 m 2 . MCQE given a significantly (p< 0.001) higher GFR values in all age groups when compared with CG and MDRD. Both the CG and MDRD formulae included around 50% of population under category with a GFR less than <90 ml/min/1.73m 2 . Conclusion:It was concluded that the present study infers with some degree of reservation that Schwartz is a good formula to provide ease of use in the daily practice in childrens and MCQE formula is acceptable for normal adult and old age group people.