I found out today that the tax year in the UK ends on April 5, and a new tax year starts on April 6. When I first read this, I was absolutely incredulous and I had to find out why. It turns out it’s because the tax system has been in place since before January 1 was considered the first day of the new year. For most of the second millennium, New Year’s Day was March 25 in England, chosen for religious reasons to coincide with Good Friday one particular year. But you may say that April 5 and March 25 are separated by almost a dozen days. Well, part of the Gregorian Calendar reform was to move New Year’s Day to January 1. England didn’t do that until 1752. In 1752, the name of the day that ended the tax year changed, but the actual day did not, so the tax year end advanced by the same number of days as the calendar moved backwards.
This means when you get your W-2 equivalent (a few of which I saw today), it lists your wages and tax withheld for the April 6 to April 5 year. If you need to file a US tax return because you’re a US citizen, you have to manually add up all the money you earned in the calendar year in order to report the right amount of income. Or hire someone to do it from all your pay stubs. That was sure fun.