Survey Sample Size Calculator

Survey Sample Size Calculator lets you cochran’s sample estimate is z²p(1−p)/e² with an optional finite population correction. Enter your own values or load the worked example.

Copy or download the computed result
Adjust confidence z score
See the processing method and limits

Method and calculation

Cochran’s sample estimate is z²p(1−p)/e² with an optional finite population correction.

Inputs and settings

Survey Sample Size Calculator accepts Confidence Z score (minimum 0.000001); Expected proportion (minimum 0.0001, maximum 0.9999); Margin of error (fraction) (minimum 0.0001, maximum 0.5); Population (0 = unlimited) (minimum 0).

Worked example

Survey Sample Size Calculator example — Confidence Z score: 1.96; Expected proportion: 0.5; Margin of error (fraction): 0.05; Population (0 = unlimited): 0. Computed output: { "sampleSize": 385 }

Output and limitations

Survey Sample Size Calculator: Assumes a simple random sample for a population proportion, excluding design effects and nonresponse.

Technical references: JavaScript numerical operations

Survey Sample Size Calculator FAQs

How does Survey Sample Size Calculator work?

Survey Sample Size Calculator applies the following rule to your input: Cochran’s sample estimate is z²p(1−p)/e² with an optional finite population correction. The worked example on this page uses the same processor as the result button.

What should I check in Survey Sample Size Calculator?

Survey Sample Size Calculator has these boundaries: Assumes a simple random sample for a population proportion, excluding design effects and nonresponse. Start by checking the confidence z score field against the units or format shown.

Can I try an example in Survey Sample Size Calculator?

Survey Sample Size Calculator provides this sample: { "sampleSize": 385 }. Use the sample button to reproduce it, then replace the inputs with your own values.