EFFECT_ADD Function (OpenOffice Calc)

• Introduced: First release not established; documented by OpenOffice.org 3.3.
• Supported in: Apache OpenOffice 4.1.16; no final supported release is established.
• Scope: English desktop Calc, Analysis add-in compatibility identity and semicolon-separated formulas.
• Checked: October 14, 2026. One ordinary English-name formula was directly entered and recalculated in 4.1.16 on Linux x86-64, Build 9816. The table contains independent references; the failed generated-ODF import is separate.

EFFECT_ADD converts a nominal annual rate into its effective annual rate for a specified number of equal compounding periods. It is the Analysis add-in compatibility function; OpenOffice’s core effective-rate function has the English name EFFECTIVE. Release implementation.

=EFFECT_ADD(NominalRate;Periods)

• NominalRate: positive annual nominal rate as a decimal, such as 0.12 for 12%.
• Periods: positive integer number of compounding periods per year.

Both arguments are required. The add-in declares Periods as a signed 32-bit integer. These examples use exact positive integers, rather than relying on fractional conversion.

These values follow the stated mathematical formulas and the inspected integer-input contract. They are not presented as eight native executions. Results are rounded to twelve decimal places where needed.

A nominal annual 12% compounded monthly uses periodic rate 0.12/12=0.01. Its effective annual rate is (1.01)^12-1, approximately 0.126825030132, or 12.6825030132%. Entering 12 instead of 0.12 would describe a nominal rate of 1200%.

With one compounding period, the effective rate equals the nominal 12%. Two periods produce 12.36%; four produce approximately 12.550881%. The larger effective amount comes from interest on earlier interest, not a change to the nominal quote.

For nominal r and m periods, the helper calculates (1+r/m)^m-1. Independently multiplying the m identical growth factors reproduces the answer. For fixed positive r, increasing the compounding frequency approaches EXP(r)-1; that limiting expression is an independent mathematical comparison, not another native case.

NOMINAL_ADD performs the inverse conversion for the same positive integer m. Preserve the full unrounded effective result when doing a round-trip; rounding an intermediate percentage can create a visible discrepancy. A nominal annual quote and an effective annual growth rate should not be labeled interchangeably.

The source rejects NominalRate≤0 and Periods<1. Those guards were inspected, while the saved reference cases cover ordinary positive rates and periods from 1 through 365. No zero-rate, invalid, overflow or precision-limit execution is claimed.

This is a fixed-rate, equal-compounding-period calculation. It does not incorporate fees, changing interest rates, actual-date day counts or irregular cash flows. The interface uses an integer period count; the behavior of a fractional or nonnumeric argument is outside the tested scope.

The directly entered English formula =EFFECT_ADD(0.12;12) produced the saved result 0.126825030132. The English entry and its serialized identity were reviewed together; an ODF canonical spelling alone cannot distinguish every core function from its compatibility add-in.

An earlier generated ODF used fully qualified Analysis service names. All eight import-path attempts for this function displayed #NAME?, despite passing recalculation controls. Those errors do not establish that the English function is unsupported. They also do not count as successful reference-case executions. Do not copy a fully qualified storage name into a normal formula expecting it to behave like the English name.

EFFECTIVE, NOMINAL, FV.

• Function-specific release implementation
• Separate English and ODF add-in identities

Only the single direct-entry case above is successful native function evidence in this guide. The remaining table values and explanatory identities are independently calculated. The failed generated-ODF workbook, including its informational attribute-load warning, is retained separately. No original XLSX execution, other locale, platform or release is implied.