Aim: To compare various intraocular lens power calculation formulae to achieve emmetropia following Cataract surgery by phacoemulsification. Materials and Methods: The present prospective study was conducted in the department of Ophthalmology, Pacific Medical College & Hospital among 240 patients undergoing cataract surgery at this centre from January 2018 –June 2019. Comparative analysis was performed using Optical Coherence Biometry (Zeiss IOL master) to measure IOL power and compare residual postoperative spherical refraction after topical Phacoemulsification using four different formulae. After 6 weeks, the analysis was completed. For the purposes of this investigation, postoperative refraction was taken at 6 weeks for all four groups of patients implanted with IOLs using four different equations. For all formulas, an optimised lens constant and an IOL with a standardised "A" constant were utilised. The IOL Master offers automatic measurement, automatic right/left detection, a graphical user interface with the most commonly used IOL power calculation formulas (SRK/T, Hoffers Q, Holladay, and Haigis), and data transfer. Results: Mean AL and ACD was higher in SRK-T group in comparison to other groups and this was statistically significant. Mean residual SRE among small eyes was higher in Hoffer Q group followed by Holladay, SRK-T and Haigis groups. Conclusion: After analysis of results, we found that over all in all eyes Hoffers Q Formula is coming as most accurate. In Small eyes as well as in Normal eyes Hoffer Q IOL formula is most accurate followed by Holladay formula, SRK-T formula and Haigis formula and In case of Large eyes Holladay formula is coming better followed by Hoffer Q, Haigis and SRK-T formula.