CUMPRINC_ADD Function (LibreOffice Calc)

• Introduced: First release not established; documented by LibreOffice 3.3.
• Supported in: Documented in LibreOffice 26.8 Help and registered in 26.8.1.1. No retirement is established.
• Scope: Desktop Calc, English compatibility function name and semicolon-separated formulas. A suffix does not by itself mean deprecated or retired.
• Checked: October 14, 2026. Eight reference calculations and the function-specific documentation were checked. Complete financial wrapper guards were not inspected. No native execution is claimed.

CUMPRINC_ADD is the Analysis add-in’s cumulative-principal function. It returns the signed principal repaid over the requested payment interval, excluding interest. It is separately registered from core CUMPRINC even when ordinary inputs produce the same amounts. Function-specific Help.

LibreOffice’s documentation describes _ADD names as compatibility variants associated with Excel 2003 behavior and recommends the unsuffixed functions for standards-oriented results. Keep the exact original function name when evaluating an imported workbook.

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

• Rate: interest rate per payment period; the references use positive rates.
• Nper: total count of equal payment periods.
• PV: positive initial loan amount in these examples.
• StartPeriod, EndPeriod: inclusive payment numbers; use integers with 1≤StartPeriod≤EndPeriod≤Nper.
• Type: documented timing flag, 0 for end-of-period payments or 1 for beginning-of-period payments.

All six arguments are required. Keep the rate and total count in the same period unit. These examples deliberately use ordinary integer counts and valid intervals; they do not establish every argument-conversion or validation branch.

These references use a constant-payment amortization model. Noninteger values are displayed to twelve decimal places; intermediate calculations retain greater precision.

For the twelve-payment loan in the first example, periods 1 through 3 repay approximately 238.919714574243 of principal. The documented cash-flow sign convention gives −238.919714574243 in the independent model, so the remaining positive balance is 1000+CUMPRINC_ADD(.01;12;1000;1;3;0), approximately 761.080285425757.

The full twelve-payment principal total is −1000. That is not the total payment outflow: interest adds approximately −66.185464140100. Keep principal reduction separate from borrowing cost in a schedule or summary.

The first end-of-period payment is approximately −88.848788678342. With interest −10, its principal component is −78.848788678342. This direct balance recurrence independently checks the cumulative add-in calculation.

For the 24-payment loan at 0.5% per period, the first twelve principal portions sum to approximately −485.041840313371; the second twelve sum to −514.958159686629. They add to −1000. With beginning timing, the first payment has no interest, so its full approximately −87.969097701328 amount reduces principal.

Use a positive rate and principal, positive integer total count, an inclusive interval within that count and Type 0 or 1 for the ordinary model shown. These are explicit assumptions for the reference calculations, not a claim that every other input produces a particular LibreOffice error.

The current financial worksheet wrapper was not included in the inspected source set. Its exact coercion and validation branches therefore remain unverified here. Fractional counts, other timing flags, zero-rate behavior, blank cells, text and extreme values were not executed. Do not copy Apache OpenOffice or core-function edge behavior onto this compatibility name without separate evidence.

CUMPRINC, PPMT, PMT.

• Function-specific Help and compatibility note
• Versioned Analysis add-in registration

The references establish the documented ordinary model. Native execution, exceptional-input behavior and cross-product equivalence remain unverified.