ACCRINTM Function (Gnumeric)

• Introduction: Listed in the grouped 0.33–0.35 release notes. This establishes an introduction within that group; the exact first release among those three is not isolated.
• Source support: Registered in the Gnumeric 1.12.62 plugin. No retirement is established. The last functioning application version is unverified for this guide.
• Evidence dates: Gnumeric 1.12.62 source was retained October 13–14, 2026 and reviewed October 15. Historical introduction evidence, GOffice 0.10.61 source and the calendar reference were retrieved October 15 where cited. Independent calendar or exact-rational calculations are labeled reference results; no native Gnumeric, headless application or GUI execution was performed.

=ACCRINTM(issue,maturity,rate,[par],[basis])

The first three arguments are required. issue and maturity are worksheet dates, rate is a positive annual rate, par is a positive face amount defaulting to 1000, and basis defaults to 0. Enter 6% or 0.06 for six percent, rather than 6. The source rejects rate zero and par zero, even though a zero-rate mathematical accrual could otherwise be imagined.

The callback computes par*rate*A/B, where A is the day count from issue to maturity and B is the annual denominator associated with the issue date. It does not compound the rate or calculate periodic coupons. The amount does not include return of principal.

The local financial day-count helper uses actual date-serial differences for bases 1–3. For basis 4 it uses 30 times the month difference plus the day-of-month difference. Basis 0 adds a special February-start adjustment for a same-year interval ending outside February. These are the inspected implementation rules; do not silently substitute a different function’s month-end algorithm. The main fixture uses the 15th of each month to avoid that ambiguity.

In basis 1, choosing the issue year’s denominator is not the same as splitting every multi-year interval across each year’s length. This implementation detail matters for comparisons with another financial library.

Create MaturityAccrual. Put =DATE(2026,1,15) in B2, =DATE(2026,7,15) in B3, 6% in B4 and 1000 in B5. Put basis values 0,1,2,3,4 in A8:A12. In B8 enter =ACCRINTM($B$2,$B$3,$B$4,$B$5,A8) and fill down.

The reference interest amounts are 30,29.753424657534,30.166666666667,29.753424657534,30. The actual interval has 181 days, while the chosen 30-day-month calculation has 180. Format the outputs as amounts without replacing their underlying formulas with rounded captions.

An equal issue and maturity date gives A=0 and returns zero when the rate and par are otherwise valid. A reversed interval is rejected when the computed day count is negative. This differs from requiring a strictly positive interval in every related security function. Invalid basis integers and failed date conversions also produce #NUM! in this callback.

For the original basis-0 fixture, change par from 1000 to 2500. Accrued interest scales from 30 to 75. Adding principal would give 2575 as a simple maturity amount for this example; ACCRINTM alone returns only 75. Changing the annual rate from 6% to 3% halves the original 1000-par interest to 15.

Now examine a separate basis-1 interval from December 31, 2023 to January 2, 2024, with par 1000 and rate 6%. The source-model amount is 120/365, approximately 0.328767123288, because both actual days use the issue-year denominator. If the interval is split at January 1, the two calls use 60/365 and 60/366 respectively. Their sum is approximately 0.328317987873, not the original amount. Splitting a calculation can therefore change the result under this implementation’s basis-1 convention.

Use DATE expressions or validated date cells rather than ambiguous typed strings. A date display and an interest-amount display serve different purposes. An unexpectedly large amount often indicates an annual rate entered as a whole number or principal mistakenly added twice.

The guide certifies documented basis integers 0–4 and ordinary numeric inputs. Fractional basis coercion, blank/text inputs, extreme dates and localized parsing were not natively tested. This is an arithmetic tutorial, not a recommendation about investment terms or a universal day-count convention. ACCRINT is a separate function with its own unresolved source issue and is not used as a cross-check here.

• Function-specific help and worksheet callback
• Gnumeric date-serial conversion and annual denominator
• Local financial day-count implementation
• Gnumeric official function catalogue

PRICEMAT, DATE.