Chi-Square Calculator

Calculate chi-square statistic to test if observed data matches expected distribution.

  • Free Online Tool
  • Instant Results
  • Mobile Friendly
  • No Installation
  • Secure & Private

Understanding This Calculator

Chi-Square Formula

Measures difference between observed and expected frequencies.

χ² = Σ [ (O - E)² / E ]

  • O: Observed Value
  • E: Expected Value

Example 1

Observed: 20, Expected: 10

  • (20 - 10)² / 10 = 100 / 10 = 10

Example 2

Observed: [10, 10], Expected: [10, 10]

  • (0)²/10 + (0)²/10 = 0 (Perfect fit)

How to Use

  • Enter observed frequencies.
  • Enter expected frequencies.

Frequently Asked Questions

How do I use the Chi-Square Test Calculator?

Enter your values in the input fields, and the result will appear instantly.

Is this calculator free to use?

Yes, this calculator is 100% free and does not require any registration or subscription.

Is it mobile-friendly?

Absolutely! Our tool is optimized for all devices, including mobile phones, tablets, and desktop computers.