This tool calculates an expression, while you are typing it.
If you'd like to know if there's an error on a receipt, the range of numbers of an RSA-2048-Key, or what's the result of 3456789^20*765512376^10*(876766776+123456789)^30/(7865-1491), then LiveCalc will be of use to you.
Typing the above expression into a typical calculator might be highly error-prone, and it might fail with the question about the RSA-Key. But with LiveCalc you can insert this expression simply via copy-and-paste or drag-and-drop into the input field, and you'll get the result immediately and in realtime. If you want to change something in your expression, just change, move and modify it. You will always see live which effect the modification has on the result.
This works far beyond the usual range of numbers. That doesn't mean that it's only interesting for "Numeric Freaks". You can use it for all kinds of everyday calculations, where you would easily lose the overview while typing into a simple calculator, or you like to compare different calculations in different windows.