Confidence Level Z Value Tool
Convert confidence levels to z critical values and margin of error.
Use this free online Confidence Level Z Value Tool to map common confidence levels to corresponding normal critical z-values. It is useful for analysis, reporting, coursework, and experiment planning when you need quick statistical evidence without building a spreadsheet. The form focuses on Confidence level (%), Population std dev (sigma), Sample size n and returns Confidence Inputs, Result, so you can move from input to answer without setting up a spreadsheet or custom script. Run one realistic example, adjust the inputs, and compare how the result changes before you copy or share it. Treat the result as a statistical aid: sample quality, independence, distribution assumptions, and context still determine whether the conclusion is valid.