Margin of Error Calculator

Calculate the margin of error for a survey estimate (proportion or mean) based on your sample size and confidence level.

1. Choose estimate type

Proportion / Percentage Mean (continuous)

Proportion: % awareness, % top-2 box, % satisfied. Mean: average rating, spend, satisfaction score, etc.

2. Enter your inputs

Sample size (n)

Number of completed interviews for this estimate.

Observed / expected proportion (%)

If unsure, use 50% – it gives the maximum (worst case) margin of error.

Confidence level

95% is typical for brand, CX and tracker studies.

Population size (optional)

Used only for finite population correction (FPC) when n is large vs population.