In case this website ever goes down, please make a note of the following alternatives: ic50.org and ic50.org.uk

Very Simple IC50 Tool Kit

Obtain IC50, EC50, etc, by online curve-fitting & get quality plots!

Point style:   x     +

Colour option:   Colour     Black and white (higher quality)

Paste in X, Y values:

Tick here and re-submit if curve-fit is bad.