Thanks for the quick responses, really helpful. That last bit of script is really sensible, stops the possible clog up of the page scripting to.
Last two questions, thanks in advanced,
Ss there anyway to have the script load the values upon page load if I had default values?
For example http://jsfiddle.net/clarkysite/XKPxe/
So that on page load it generates the values from the defaulted inputs, then when a new value is entered it continues as it does now?
And also is there anyway to add a prefix to the result, for example a letter or symbol?
Thanks for all your help, very much appreciated!