CUMPRINC Function (OpenOffice Calc)

• Introduced: First release not established; documented by OpenOffice.org 3.3.
• Supported in: Apache OpenOffice 4.1.16; this is a verified release, not a final supported version.
• Scope: Desktop Calc, English function names and semicolon-separated formulas.
• Checked: October 14, 2026. Eight ordinary reference formulas were recalculated from generated ODF in 4.1.16 on Linux x86-64, Build 9816. Source and independent arithmetic were checked.

CUMPRINC totals the principal portions of payments from StartPeriod through EndPeriod, inclusive. For a positive loan principal it returns repayments with a negative sign. It does not return the remaining positive balance or include interest. The native examples exercise the core CUMPRINC identity, not the separate CUMPRINC_ADD compatibility name. Release implementation.

=CUMPRINC(Rate;Nper;PV;StartPeriod;EndPeriod;Type)

• Rate: interest rate per payment period, strictly positive for these cumulative functions.
• Nper: total number of payment periods; use a positive integer for an ordinary schedule.
• PV: positive loan principal.
• StartPeriod, EndPeriod: inclusive payment numbers from 1 through Nper. The implementation floors these two arguments.
• Type: 0 for end-of-period payments or 1 for beginning-of-period payments. All six arguments are required.

The native column contains saved 4.1.16 results; independent references use high-precision arithmetic and the stated source rules. Values are shown to twelve decimal places where needed.

A 1000 loan at 1% per period over twelve end-of-period payments repays approximately 238.919714574243 of principal in the first three payments. The function returns the negative of that amount. The remaining balance is therefore 1000+CUMPRINC(.01;12;1000;1;3;0), approximately 761.080285425757.

Across all twelve payments, principal portions sum to −1000. Interest is additional: the payment total is approximately −1066.185464140100. Do not describe the −1000 principal total as the total borrowing cost.

Each principal portion equals the signed payment minus its signed interest portion. The first end-of-period payment has interest −10 and principal approximately −78.848788678342. Updating the outstanding balance and repeating this calculation independently reproduces the cumulative values.

For a 24-payment loan at 0.5% per period, the first twelve payments repay approximately 485.041840313371 of principal; the second twelve repay 514.958159686629. Their total is 1000. At beginning timing, the first payment has no interest and its entire approximately 87.969097701328 amount is principal.

The implementation requires positive rate, Nper and PV and a valid inclusive interval within the schedule. Its checks were reviewed without executing invalid cases. A rate of zero is rejected by this cumulative function; an ordinary zero-interest principal schedule can instead be written as equal principal installments.

StartPeriod and EndPeriod are floored. Type is best kept to 0 or 1; positive values follow the beginning-payment branch in the core helper. Keep rate and Nper in the same time unit. A monthly rate paired with a number of years describes a different schedule, even if the formula calculates successfully.

PPMT, CUMIPMT, PMT.

• Function-specific release implementation
• ScGetRmz calculation
• ScGetZw calculation

The generated ODF produced the informational load warning “Not all attributes could be read.” The sheet was hard-recalculated and saved separately. All eight ordinary function identities, inputs and results were reconciled; a stale SUM cache changed from 999999 to 3 and an uncached SUM returned 7. This establishes the stated examples, not every workbook style or invalid input. Other explanatory identities are independent calculations. The authoring-tool XLSX was not executed in OpenOffice, and its preview values are not the native results reported here.