Computes areas (probabilities) under a chi-square curve. Chi-square values are never negative and the curve is right-skewed, so tests using it (goodness-of-fit, independence) rely on the right tail.
The buttons above the chart choose which area is shaded and reported:
The calculator works in both directions — edit whichever value you know:
You can also drag the boundary line(s) directly on the chart. The banner beside the buttons reports the current area.
Set Degrees of freedom with the number box or the slider. More df shifts the curve rightward and makes it more symmetric.