YEARFRAC Function (Gnumeric)

=YEARFRAC(start_date, end_date, [basis])

start_date — Required. Beginning date serial or date-cell reference.

end_date — Required. Ending date serial or date-cell reference.

basis — Optional. Day-count convention, default 0 (US 30/360). Gnumeric 1.12.62 accepts 0 through 4; unsupported values and invalid dates give #NUM!.

The official Gnumeric date header and gnumeric_yearfrac code define the basis table:

On a narrow screen, scroll this table sideways to see every column.

Gnumeric formulas here use commas and DATE(year,month,day) to avoid regionally ambiguous date strings. The output is numeric, and changing the cell’s date format does not change the underlying fractional value. A 0.00 format can hide meaningful precision, so add more decimal places when comparing bases.

The interval January 1 through July 1, 2024 contains 182 elapsed days (2024 is a leap year). Try these formulas:

On a narrow screen, scroll this table sideways to see every column.

Results are rounded here for display; sheet cells can show additional digits. These are independently calculated expectations, not results obtained by executing Gnumeric 1.12.62. For basis 1 the actual/actual method may depend on whether the interval spans years; test the precise required convention in your installed version before using it for financial reporting.

Reproducible input table

Expected D2: approximately 0.498630137. Formatting A2 and B2 as dates and D2 as a number with nine decimals makes the comparison easier.

If E2 contains an annual fee (for example 1200), a simple Actual/365 prorated fee for the A2–B2 interval is:

=E2*YEARFRAC(A2,B2,3)

With the example dates and E2=1200, the independently calculated expected result is approximately 598.3561644 before currency rounding. Apply your organization’s contractual day-count convention instead of assuming Actual/365 is universally correct.

Check the order of user-entered dates before calculating:

=IF(B2<A2,"Check date order",YEARFRAC(A2,B2,3))

This guard is useful for preventing an unexpected negative or reversed-duration report; it is a validation policy, not an assertion that Gnumeric necessarily rejects reversed dates.

• #NUM!: the tagged source rejects an invalid date or a basis outside its accepted range of 0–4. Check input cells and selected basis.
• Unexpected fraction: the default is US 30/360, not actual-day / 365. Specify basis explicitly in financial models.
• End-of-month differences: US and European 30/360 can disagree at month ends. Test the convention required by your contract and audit a known example.
• Leap days: 2024 has 366 days, but basis 3 still divides actual elapsed days by 365. That is an intentional definition, not a leap-year adjustment.
• Locale and dates: enter dates with DATE() or references to validated date cells; CSV strings like 03/04/2024 may parse differently.
• Excel/LibreOffice compatibility: day-count basis codes 0–4 are common, but exact edge cases (1900 date system, month ends, actual/actual intervals) and imported date-system settings require target-application testing. No cross-application native equivalence was established in this review.

DATE · DAYS360 · YEAR · EDATE · EOMONTH

• Gnumeric public function catalogue — checked October 11, 2026; the public project lists YEARFRAC as Complete / No Testsuite.
• Gnumeric 1.12.62 Date/Time implementation — help_yearfrac, gnumeric_yearfrac, and the function descriptor, inspected October 11, 2026.
• Gnumeric 1.12.62 day-count basis definitions — GNM_DATE_BASIS_HELP, inspected October 11, 2026.

The syntax and behaviour are based on the Gnumeric references cited above. The sample calculations were independently checked; they are expected results, not outputs observed in Gnumeric. Test locale-sensitive text conversion and imported files in your own installation. View the example-check record.

Official YEARFRAC reference · Editorial standards