Chi-square calculator
Run Pearson’s chi-square test of independence on a 2×2 count table and inspect expected counts and low-count warnings. The calculation runs in your browser; your inputs stay on this device.
Chi-square test of independence
Enter a 2 × 2 table of observed counts. The calculator reports expected counts and warns when the large-sample approximation is weak.
Formula and assumptions
Pearson X² = Σ (observed − expected)² ÷ expected, with one degree of freedom for a 2×2 table. Expected counts under 5 trigger a warning because the large-sample approximation may be weak.
These estimates assume independent observations and simple random samples where applicable. They do not adjust for complex designs, weighting, clustering or multiple comparisons. Read the result with the underlying study design in mind.
More statistics tools
Open the complete statistics workbench
Frequently asked questions
Are my inputs sent to PulseLake?
No. The calculation runs in your browser; the form does not submit the values, and these calculators do not use a server-side analysis service.
Do these results handle weighting or complex survey samples?
No. The methods assume independent simple random observations and do not account for weighting, clustering, repeated measures or nonresponse.
Does statistical significance establish practical importance?
No. Review the interval and whether effects of that size matter for the decision. A non-significant result does not prove groups are identical.
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