The Margin of Error Calculator is an essential statistical tool designed to help researchers, analysts, and business professionals determine the accuracy of their sampling results. This powerful calculator enables users to compute precise confidence intervals for various types of statistical data, particularly useful in market research, opinion polls, and scientific studies. Whether working with proportion data or requiring specific confidence levels, the calculator provides accurate measurements that help validate your research findings and support data-driven decisions. Professionals can easily assess the reliability of their sample data and determine how well their results represent the entire population. For businesses conducting market research or organizations analyzing survey data, this tool ensures statistical rigor and helps maintain high standards of data accuracy. Start using our Margin of Error Calculator today to enhance the precision and credibility of your statistical analysis.
Type a sample size, pick a confidence level, and the calculator instantly shows your margin of error. A 95 % level with n = 400 returns ±4.9 %—the maximum error most national polls accept (AAPOR, 2021). Use the other mode to see how large a sample you need to hit any target MOE.
A margin-of-error tells you how far your sample result can stray from the real population value. Plug in sample size, deviation or proportion, and a confidence level—the calculator returns the ± error and a full confidence interval. Larger samples shrink the error: at n = 1 000 and p = 0.5 the 95 % MOE ≈ ±3.1 % (U.S. Census Bureau, 2022).
