Date & Time
DAYS360 function: count days under 30/360 US and European bond conventions
Calculate 30-day-month interest accrual periods using DAYS360 and understand how US (NASD) and European month-end rules differ.
30/360 day-count conventions in commercial paper and bonds
DAYS360(start_date, end_date, [method]) calculates the number of days between two dates assuming twelve 30-day months (360-day year). Set method to FALSE (or omit) for US NASD rules, or TRUE for European 30E/360 rules.
Over a full quarter from 2026-01-15 to 2026-04-15, DAYS360 returns 90 days regardless of February having 28 days.
=DAYS360(A2, B2, FALSE)Try the example
Use the original values or change them to test your understanding.