Why Does the UK Tax Year End on 5 April? (And Not a Normal Date Like Everyone Else’s?)

If you’ve ever looked at your calendar, seen “Tax Year Ends – 5 April” and thought, “Why? Why not the end of March? Or 1 January like a sensible country?” — congratulations, you’re officially British. Confused and mildly irritated by bureaucracy.

So, why does the tax year end on 5 April? Buckle up — it’s time for a tale of old calendars, ancient kings, and some truly awkward accounting decisions that we just never bothered to fix.

Blame the Romans. Obviously.

Once upon a time, the UK used the Julian calendar, introduced by Julius Caesar in 45 BC — because who better to manage your timekeeping than a man in a toga?

Back then, the new year began on 25 March, also known as Lady Day. This was one of the quarter days — used for paying rent, settling debts, and probably deciding which cow belonged to whom.

So yes — 25 March was basically the OG tax deadline.

Then Along Came the Pope

Fast forward to 1582. Pope Gregory XIII (whose hobbies included maths and confusing nations) realised that the Julian calendar was out of sync with the sun by about 11 minutes per year. Over centuries, that added up. Seasons were drifting. Easter was wobbling. It was chaos.

So the Gregorian calendar was born, correcting the drift by skipping 10 days. Most of Europe said, “Cool, makes sense, let’s do it.”

Britain said, “Absolutely not. We’ll keep our weird calendar and our weird ways, thank you.”

We eventually gave in — but not until 1752. By then, the drift was up to 11 days.

The Year We Lost 11 Days (No, Really)

In 1752, the UK finally adopted the Gregorian calendar. To catch up, we jumped from 2 September straight to 14 September overnight.

People were understandably furious — “Give us back our 11 days!” they cried. (There were even riots, probably fuelled by the fear of missed birthdays and ghost rent payments.)

Now here’s the fun bit: the government didn’t want to lose out on 11 days of tax. Because, let’s face it — if there’s one thing more eternal than time, it’s tax.

So rather than adjusting the tax year to start on the new 25 March, they just pushed it 11 days later — to 5 April. And there it has remained ever since, quietly baffling freelancers, accountants, and anyone with a calendar.

Could We Change It?

Yes. Will we? Probably not. It’s tradition now — like warm beer, drizzle in July, and pretending to understand the offside rule.

Plus, imagine the chaos of adjusting every payroll system, HMRC form, pension contribution, ISA deadline… it's enough to make a spreadsheet cry.

Final Thoughts

So next time you're filing your tax return and muttering, "Why the 5th of April?", remember: it’s all thanks to Julius Caesar, a Pope, 11 missing days, and a government that refused to lose out on a single penny.

And honestly, there’s nothing more British than that.