Modify the truth table by pressing the output column values you wish to change. The values cycle between 0, 1, and d (don't care).
The x !y icon computes and views the minimized sum-of-products expression. The truth table icon above it goes back to the truth table.
The green + adds a new variable, up to a maximum of 10. There is no way to modify the characters used for the variables.
The red x removes a variable, down to a minimum of 2.
(KarnaughCalc is based on a small portion of Logisim, an open-source, Java-based application for designing digital circuits built by the same author.)
(KarnaughCalc is licensed under a Creative Commons Attribution-Share Alike 3.0 License. Based on the original at http://www.cburch.com/karnaugh/.)