Sumfern

Sumfern is a set of free US and Canada pay and tax calculators where every page shows its working. Each calculator lists the formula, walks through an example with round numbers you can check by hand, and links the official source behind the rates: IRS and Department of Labor for US wages and withholding, Canada Revenue Agency for GST and HST. Rates that change each year are named with the year, and a build check stops the page from publishing if a figure disagrees with its source. No sign-up, no ads in the way of the result, nothing stored about what you type. Built for people who want to verify a paycheck, an overtime bill or a tax figure instead of trusting a black box.