How to Use the Sample Size & Margin of Error Calculator
- Enter your total target population size (or leave large for infinite population).
- Select your desired Confidence Level (90%, 95%, or 99%).
- Enter your acceptable Margin of Error percentage (e.g. ±5%).
- The calculator computes the exact number of survey respondents required.
Key Features & Capabilities
- Cochran’s statistical sample size formula with Finite Population Correction (FPC).
- Supports 90%, 95%, and 99% critical Z-score confidence levels.
- Essential for market researchers, UX testers, and academic researchers.
Technical Architecture & Privacy
Sample Size & Margin of Error Calculator is engineered with a focus on performance, mathematical accuracy, and maximum user privacy. Operating entirely in-browser on the client side, all processing takes place locally within your browser's JavaScript engine. None of your financial numbers, text entries, or private inputs are ever transmitted to or stored on remote servers.