Sample Size Calculator

Calculate the required sample size for surveys and research studies with confidence intervals and margin of error

Study Parameters

Confidence Level (%)

How confident you want to be in your results

Margin of Error (%)

Acceptable range of error in your results

Expected Proportion (%)

Expected percentage of positive responses (use 50% if unknown)

Finite population (known total size)

Formula

n = (Z² × p × (1-p)) / e²

Common Study Types

Results

Set your study parameters and click Calculate to see the required sample size

Sample Size Guidelines

Confidence Levels

90%: Exploratory research

95%: Standard for most studies

99%: High precision required

99.9%: Critical applications

Margin of Error

±1-2%: High precision studies

±3-5%: Standard surveys

±5-10%: Exploratory research

>±10%: Preliminary studies

Best Practices

Use 50% proportion if unknown

Account for non-response rate

Consider practical constraints

Pilot test when possible

Tips

Enter the dimensions in the same unit for consistency.
Results update automatically as you type.
Use the unit selector to convert between different measurement systems.

Sample Size Calculator

Study Parameters

Formula

Common Study Types

Results

Sample Size Guidelines

Confidence Levels

Margin of Error

Best Practices

Tips

Volume Calculators

Finance Calculators

Sample Size Calculator

Study Parameters

Formula

Common Study Types

Results

Sample Size Guidelines

Confidence Levels

Margin of Error

Best Practices

Tips