EFFECT_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.

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; LibreOffice documents the unsuffixed counterpart as EFFECT. 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.

=EFFECT_ADD(NominalRate;Periods)

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

Both arguments are required. The reference model uses positive rates and positive integer frequencies. Fractional-period conversion and endpoint validation are outside the checked scope.

These references use the annual compounding relationship. Noninteger values are displayed to twelve decimal places; intermediate calculations retain greater precision.

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 independent compounding formula is (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 ordinary references use positive rates and integer frequencies from 1 through 365. No zero-rate, invalid, overflow or precision-limit execution is claimed. The documented syntax alone does not establish a particular error code or fractional-frequency conversion rule.

This fixed-rate compounding model does not include fees, changing interest rates, actual-date day counts or irregular payments. The current financial worksheet wrapper was not inspected, so its complete input guards are unverified. The reference calculation and documented purpose must not be mistaken for native execution or a guarantee of agreement with another spreadsheet product.

EFFECT, NOMINAL, FV.

• 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.