Online Tools

Some useful tools and calculators I've created using PHP.

ISBN Check Digit

A random script to calculate the check digit for an ISBN number. It also provides a link to the book-search page on Wikipedia.

The calculator is available on the ISBN Check Digit page.

A simple script to calculate how much PayPal will charge for a given transaction amount.

The calculator is available on the PayPal Fee Calculator page.

A simple script to calculate roughly how much an electrical appliance will cost over a number of time periods..

The calculator is available on the Power Consumption Cost page.