How to Count Days on a 360-Day Calendar with DAYS360 in Excel

Count days the way lenders do with DAYS360: 30-day months, accrued interest, and the US versus European month-end rule.

You will learn to

• Count days on a 30/360 basis
• Calculate accrued interest with DAYS360
• Compare the US and European methods

How it works

DAYS360(start_date, end_date, [method]) counts the days between two dates as if every month had 30 days and the year 360. Many loans, bonds and accounting systems use this 30/360 convention, so interest is the same every month.

The optional method changes how the 31st is treated. FALSE (US/NASD, the default) turns an end date of the 31st into the 1st of the next month unless the start date is the 30th or 31st. TRUE (European) simply treats every 31st as the 30th, so the two methods can differ by a day.

=DAYS360(B2,C2)