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Both calculators run independently — change the inputs on either side to compare results.

Margin of Error Calculator

Find the margin of error for a survey proportion at a chosen confidence level. Tells you how far a poll result might be from the true population value.

Sample Size (people)

Sample Proportion (%)

Z-Score (1.96 = 95%)

Probability

Sample Size Calculator

Determine the minimum sample size needed for a survey or experiment given your confidence level, margin of error, and population size. Prevents under-powered studies and over-budgeted data collection.

Population Size (N) (people)

Confidence Level

Margin of Error (%)

Response Distribution

Key differences

	Margin of Error Calculator	Sample Size Calculator
Category	Statistics	Probability
Inputs required	3	4
Result	Margin of Error (%)	Required Sample Size (samples)
What it does	Find the margin of error for a survey proportion at a chosen confidence level. Tells you how far a poll result might be from the true population value.	Determine the minimum sample size needed for a survey or experiment given your confidence level, margin of error, and population size. Prevents under-powered studies and over-budgeted data collection.