Extinction strain rate „a‟, like laminar flame speed, is a fundamental characteristic of fuel-oxidizer combination. Available data for „a‟ from counter flow diffusion flame experiments from earlier studies using opposed jet (straight and contour nozzles) and Tsuji burners have been compiled; data from a Tsuji burner developed in our laboratory to cross-check earlier results is also included in the analysis. Geometric and associated boundary conditions and strain rate definitions are shown to be responsible for the observed variations in „a‟ obtained using specific burner for a given fuel-oxidizer combination. Measured variations in „a‟ with geometric parameters, cylinder diameter in case of Tsuji type and nozzle separation in opposed jet type with straight nozzle, are shown to tend to similar asymptotic values (about 375−1 for CH4Air, for instance), which can be taken to be the extinction strain rate. Numerical results obtained using FLAMEMASTER [1] is shown to follow the same asymptotic trend. The opposite trend, that is, decreasing extinction global strain rate with increasing L/D observed by Sarnacki et al [2] using contour nozzles is due to the use of actual nozzle separation distance instead of the effective separation distance known as free floating length, LFF in calculating strain rate. The corrected strain rates obtained by using the effective separation distance is shown to be consistent with the other results and the asymptotic value matches reasonably well with local strain rates reported in Sarnacki et al [2]. © 2018 Combustion Institute. All rights reserved.