What is the Two-Proportion z Statistic Calculator?
Calculate the pooled z statistic for two independent proportions. ITS Research Solution keeps the interactive tool above the explanation so you can calculate first and then review the method used.
Formula or method
z = (p1−p2) / √[p(1−p)(1/n1+1/n2)], using the pooled proportion p.
How to use this tool
Enter the requested values using consistent units, run the calculation and review the main result plus any supporting values. Compare two event proportions from independent groups.
Interpretation and limitations
For small cell counts, exact alternatives may be more appropriate. Always check source data, units, rounding and discipline-specific requirements before using a result in assessed, published, regulated or high-stakes work.
Frequently asked questions
How is this result calculated?
z = (p1u2212p2) / u221a[p(1u2212p)(1/n1+1/n2)], using the pooled proportion p.
Can I use this result in formal academic or research work?
Use it as a transparent calculation aid, then verify the assumptions, units, rounding and any institution-, journal- or field-specific requirements before formal use.