Date & Time

DAYS360 Function in Excel

Returns the number of days between two dates based on a 360-day year.

Syntax

  • =DAYS360(start_date, end_date, [method])

Arguments

  • start_date (required): Start date
  • end_date (required): End date
  • method (optional): FALSE=US, TRUE=European

Examples

  • =DAYS360("1/1/2024", "12/31/2024") - Days in 360-day year - Result: 360

Excel DAYS360 function documentation

  • DAYS360 computes day counts based on a 360-day year financial convention.
  • Syntax: =DAYS360(start_date, end_date, [method]). Common in bonds and accounting schedules.
  • Use DAYS360 when contracts specify 30/360 rules instead of actual calendar days.
  • Category reference: [/categories/date-time/](/categories/date-time/).

DAYS360 syntax and method argument

  • start_date and end_date are required and should be valid date serials.
  • method FALSE or omitted uses US (NASD) 30/360 behavior.
  • method TRUE uses the European 30/360 convention with different month-end handling.
  • Always document the chosen convention for audit consistency in finance models.

Step-by-step: accrue monthly interest

  • Step 1 - Enter loan start date in A2 and end date in B2.
  • Step 2 - Compute day count: =DAYS360(A2,B2).
  • Step 3 - Convert to year fraction by dividing result by 360.
  • Step 4 - Multiply principal * rate * (DAYS360/360) for accrued interest.

DAYS360 vs DAYS vs YEARFRAC

  • DAYS360 follows contractual 30/360 assumptions for standardized finance calculations.
  • DAYS uses actual calendar differences and is better for operations reporting.
  • YEARFRAC can represent multiple basis options, including actual/actual approaches.
  • Combine presentation labels with [TEXT](/functions/text/) when exporting reports.

Worked examples to copy

  • US method default: =DAYS360(A2,B2).
  • European method: =DAYS360(A2,B2,TRUE).
  • Accrual fraction: =DAYS360(start_date,end_date)/360.
  • Interest estimate: =principal*rate*DAYS360(A2,B2)/360.

People also ask

  • Why use DAYS360 instead of DAYS? - Financial contracts often require 30/360 conventions.
  • What does method TRUE mean? - It applies European 30/360 counting rules.
  • Can DAYS360 differ a lot from DAYS? - Yes, especially around month-end dates.
  • Is DAYS360 good for payroll? - Usually no; payroll often uses actual calendar days.

Common errors

  • Different from actual calendar days

Use cases

  • Financial calculations
  • Interest accrual
  • Accounting

Frequently asked questions

  • What is DAYS360 used for? DAYS360 calculates days between dates using a 360-day year (12 months × 30 days). This convention is used in finance for interest calculations, bond pricing, and accounting where standardized month lengths simplify calculations.
  • Why use 360-day year instead of actual days? The 360-day convention makes interest calculations simpler and more predictable. Each month has exactly 30 days, so monthly interest is exactly 1/12 of annual. Many bonds, loans, and financial instruments use this convention.
  • What's the difference between US and European method? Method FALSE (US/NASD): adjusts end-of-month dates specially. Method TRUE (European): if either date is 31st, it becomes 30th. US method is more common in American finance; European method is used in some international contexts.

Editorial review

  • Reviewed by Excel.Directory Editorial Team. Updated May 2026.

When to use DAYS360

  • Financial calculations — common Date & Time scenario for DAYS360.
  • Interest accrual — common Date & Time scenario for DAYS360.
  • Accounting — common Date & Time scenario for DAYS360.

DAYS360 in the Date & Time category

  • Browse all Date & Time functions at /categories/date-time/ for related formulas.
  • DAYS360 syntax: =DAYS360(start_date, end_date, [method])
  • start_date (required): Start date
  • end_date (required): End date
  • method (optional): FALSE=US, TRUE=European
  • Confirm DAYS360 arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.

Formula checklist before you copy down

  • Confirm DAYS360 arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.
  • If results look wrong, check for text stored as numbers and invisible spaces with TRIM.
  • Spot-check three known input rows manually against expected output.

Related Excel functions

  • DAYS (/functions/days/): Returns the number of days between two dates.
  • DATEDIF (/functions/datedif/): Calculates the number of days, months, or years between two dates.
  • YEARFRAC (/functions/yearfrac/): Returns the fraction of the year represented by the number of days between two dates.

Errors to watch for

  • Different from actual calendar days — review causes on linked error pages in the directory.

Copy-paste audit workflow

  • Enter DAYS360 on three test rows with known expected output documented on a QA tab.
  • Fill down only after absolute references are locked on lookup tables and rate tables.
  • Compare against manual calculation or a calculator for financial and statistical functions.
  • Search this directory for comparison guides when choosing between similar functions in the same category.

DAYS360 worked examples to copy

  • =DAYS360("1/1/2024", "12/31/2024") — Days in 360-day year. Expected result: 360.

DAYS360 reference summary for crawlers and offline review

  • DAYS360 belongs to the Date & Time category in Excel. Returns the number of days between two dates based on a 360-day year.
  • Full syntax: =DAYS360(start_date, end_date, [method]). Open /functions/days360/ for parameters, FAQs, and related pages.
  • Common mistakes: Different from actual calendar days
  • Pair this function with comparison guides when another Excel formula might fit the same task better.
  • Review fix-excel-formula-errors when unexpected errors appear after upgrading Excel or sharing across locales.