CUMIPMT Function (Gnumeric)

• Introduced: 1.1.6, according to the official release history. This was a development-series release.
• Availability: Supported in Gnumeric 1.12.62, based on the function-specific registration.
• Scope: Desktop; the fn-financial function module must be included and enabled.
• Checked: October 14, 2026. Documentation/source check; no new native test in Gnumeric 1.12.62.

This page concerns Gnumeric (GNOME’s spreadsheet application), not the identically named feature in another spreadsheet. The official Gnumeric Finance reference documents the signature and behaviour, and the public function catalogue lists the function’s implementation as Complete with Basic upstream testing (both checked 2026-10-13). The Gnumeric 1.12.62 release announcement confirms the target release exists, but this manuscript does not establish that every supported operating-system package ships identical binaries or that our examples ran in that version. Consult your distribution’s Gnumeric package and function list. These are finance functions, not optional add-ins asserted to be available on every platform.

Formula syntax below uses the English function name, decimal point and comma-separated arguments shown by the English Gnumeric reference. Some installations use a localized decimal separator and/or argument delimiter; check the on-screen Function Selector and adapt syntax rather than pasting commas blindly. Put percentage values in cells as numbers formatted as percentages (for example, 6% = 0.06); do not type the number 6 when you mean six percent.

CUMIPMT returns the total interest portion of fixed loan payments from a starting period to an ending period. This is useful when budgeting financing costs by quarter or fiscal year, validating an amortization schedule, or separating interest from principal on a debt. It does not return the outstanding loan balance, the total loan instalments, or an accrual by arbitrary calendar dates. The official Gnumeric Finance manual describes it specifically as cumulative interest paid on a loan. Gnumeric Finance manual, CUMIPMT, checked 2026-10-13.

=CUMIPMT(rate,nper,pv,start_period,end_period,type)

The six-argument ordering is documented. The shared manual note calls 0 the default, but the verified 1.12.62 registration requires six numeric arguments; therefore this guide requires an explicit type. The official reference does not establish all rounding/coercion behaviour for fractional periods; use integer payment numbers in reviewed examples. Gnumeric Finance manual, CUMIPMT.

These examples use a $12,000 initial loan, 6% nominal annual interest, 12 equal monthly repayments, and payment at the end of each month. Gnumeric’s finance manual calls the first argument rate and explicitly defines it as per period; therefore use 6%/12, not 6%, when payments are monthly. Use the conventional finance signs: the loan received is positive, while payments made by the borrower are negative. Gnumeric manual — CUMIPMT, CUMPRINC, PMT.

Keep full precision in B7 for follow-on calculations; formatting a cell to two decimals is different from manually rounding intermediate values. The PMT expression is consistent with the constant-payment annuity identity -12000*(0.005)/(1-(1.005)^-12). Independent calculation finds -$1,032.80 per month to cents.

Create an independent amortization check: put periods 1 through 12 in A12:A23. In B12 enter =IPMT($B$3,A12,$B$4,$B$5,0,$B$6); in C12 enter =PPMT($B$3,A12,$B$4,$B$5,0,$B$6); fill both down to row 23. This produces a proposed formula-by-formula comparison, not a recorded Gnumeric run. The first expected row is interest -60.00, principal -972.797156485; each row’s signed interest + principal should equal $B$7. Official Gnumeric manual — IPMT and PPMT.

With B3:B6 filled as above, enter each function directly in a free cell:

The negative sign denotes interest the borrower pays. To display an absolute expense total instead, a reporting-only formula such as =-CUMIPMT($B$3,$B$4,$B$5,1,3,$B$6) produces +165.383722724 without changing the underlying cash-flow convention. Do not mix negated and signed results in one reconciliation.

Independent hand calculation for the first three months

Using payment -1,032.797156485:

So interest in months 1–3 is -60 - 55.1360142176 - 50.2477085062 = -165.3837227238, matching the independent financial calculation above. The comparison to the Gnumeric formula is an expected result only, since this review did not execute Gnumeric.

If A12:A23 contain 1…12 and B12:B23 contain the expected IPMT expressions from the setup, then =SUM(B12:B14) is the independent months 1–3 interest total; compare it to =CUMIPMT($B$3,$B$4,$B$5,1,3,$B$6). Each subsequent three-month block can be checked in the same way. For a report with user-input period bounds E2=4 and E3=6, reference them directly with =CUMIPMT($B$3,$B$4,$B$5,E2,E3,$B$6); expected -121.168264316. Validate that 1 <= E2 <= E3 <= $B$4 before relying on a selected period window.

For an audit of all loan instalments, independently calculated all-period interest (-393.565877820) plus all-period principal (-12000.000000000) equals twelve payments (-12393.565877820), within floating-point tolerance. This provides a stronger check than verifying a single month. Related documented Gnumeric functions: IPMT, PPMT, PMT.

• rate entered as annual when periods are monthly: six percent per month is a very different loan. Use annual nominal divided by 12 only when the agreement actually calls for 12 equal monthly rate periods; real loan day-count terms can differ.
• Payment timing mismatch: with type=1, beginning-of-period payments alter the amortization (the first scheduled payment typically has no accrued first-period interest in the simple model). Do not compare those to a type=0 audit without changing the schedule. Specific Gnumeric native outputs for type=1 remain untested.
• Reversed or out-of-bounds periods: start_period > end_period, periods below 1 or above nper are unsuitable for an amortization interval; prevent them with input validation. The precise displayed error code is not claimed as observed.
• Zero/negative or text arguments: a zero rate requires special handling in some finance implementations; fractional period counts and text coercion were not tested here. Use a positive numeric periodic rate, positive present value, and whole period bounds for the reviewed examples.
• Irregular, floating-rate and balloon loans: the simple CUMIPMT model assumes constant periodic rate and regular instalments; construct a cash-flow schedule for nonstandard contracts instead.
• Rounding to cents: financial institutions often round each payment/interest entry, whereas worksheet formulas keep more precision. Reconcile at appropriate tolerance and avoid promising cent-for-cent lender-statement equality.
• Locale and function availability: use the English signature shown above as a reference, not an assertion about the argument separator on every installation.

• CUMPRINC — cumulative principal in the same interval
• IPMT — interest for one payment number
• PPMT — principal for one payment number
• PMT — equal repayment each period
• NPER — total number of periods

Official sources were checked on 2026-10-13:

1. Gnumeric manual — Finance function reference: exact Gnumeric signature, argument names, purpose and documented defaults; relevant function heading CUMIPMT. This is documentation evidence, not an execution trace.
2. Gnumeric official function catalogue: lists cumipmt as Complete / Basic; catalogue classification is not a guarantee that this manuscript’s test values passed a native session.
3. GNOME Gnumeric 1.12.62 release announcement: version context. The web reference is updated separately from specific installed builds, and the reviewed implementation is scoped to the checksum-verified official 1.12.62 source archive. No native application execution was performed.

Validation scope: Official documentation and checksum-verified Gnumeric 1.12.62 source were reviewed; example arithmetic was independently recalculated. Native Gnumeric execution, screenshots, locale/platform regression tests and workbook round-trips were not performed.