How Many Days Are in a Fiscal Year?
Fiscal years aren't always 365 days. Here's how US federal, UK, and corporate 52/53-week fiscal years work, and how to count their days correctly.
A fiscal year is just the 12-month window a government or company uses for accounting. It doesn't have to match the calendar year. And depending on the convention, it doesn't even have to be 365 days.
Standard 12-month fiscal years
The US federal government runs October 1 to September 30. The UK government runs April 6 to April 5. Most companies either follow the calendar year or pick a similar 12-month window that suits their season.
The 52/53-week fiscal year
Plenty of retailers (think Apple, Walmart, Cisco) use a 52/53-week fiscal year that always ends on the same weekday, usually the Saturday closest to a fixed month-end. Most years come out to 52 weeks (364 days).
Every five years or so you get a 53-week year (371 days) to keep things lined up. That's the reason a quarterly report sometimes hides a mysterious 14-week quarter.
Counting days inside a fiscal year
For accruals, prorations, and SaaS billing, count actual days. Don't assume every month is 30. Our Date Difference Calculator gives the exact count (leap days included), and the Business Days Calculator gives you working days for SLAs and labor.