Free Margin of Error Calculator
Calculate the margin of error for a confidence interval given the z-value, standard deviation, and sample size.
Margin of Error
2.3520
Standard Error1.2000
Relative Margin (%)19.6000
Margin of Error vs Z-Value
How to Calculate Margin of Error
Formula
E = z * (sigma / sqrt(n))
The margin of error is the half-width of the confidence interval. It depends on three factors: the confidence level (via z), the variability of the data (sigma), and the sample size (n). A smaller margin of error means a more precise estimate.
Example Calculation
z = 1.96, SD = 12, n = 100. What is the margin of error?
- 01Standard Error = 12 / sqrt(100) = 12 / 10 = 1.2
- 02Margin of Error = 1.96 * 1.2 = 2.352
- 03The sample mean will be within +/- 2.352 of the population mean with 95% confidence.
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