PlanMaker ISERR: Separate calculation failures from unavailable values

The PlanMaker 2026 reference, 2024 reference and 2021 reference were retrieved and compared on October 15, 2026. They document this function’s core operation. Documented by 2021 is not an original introduction date; the first introduction and any last-working-version endpoint remain unverified. The 2026/NX manual family does not establish per-build availability in FreeOffice, mobile clients or every operating system.

The examples below are vendor-supported controls and independently modeled expectations. No native PlanMaker execution, screenshot capture or workbook interchange test was performed. Keep the distinction between documentation support and observed application behavior when applying the guide to an installed version.

=ISERR(Cell)

There is one required argument and no documented optional default. Use a single-cell reference such as A2 for the worked tests. The examples deliberately keep the inspected value in a visible source cell. The formulas use English function names. The one-argument call needs no list separator; nested helper formulas below use commas, which may need adjustment for the installed locale.

SoftMaker explicitly contrasts ISERR with ISERROR and says a cell containing NA() produces FALSE for ISERR. The help’s example occasionally abbreviates the label as #NA, but the defined exception is #N/A. Do not turn that typography into a new error category.

Create ErrorClasses with Value, Other_error, Missing and Any_error in A1:D1. Fill B2 =ISERR(A2), C2 =ISNA(A2) and D2 =ISERROR(A2) through row 8 after entering these A values:

Rows 3, 4 and 5 all make ISERR FALSE, but they are not interchangeable values. On a copy, change A2 to =NA(): B2 becomes FALSE, C2 becomes TRUE, and D2 remains TRUE. The error has been reclassified, not repaired. Changing it instead to numeric 12 makes all three flags FALSE.

Create RatioReview. Enter Numerator, Denominator, Result and Action in A1:D1. Use these A:B inputs: row 2 24,6; row 3 10,0; row 4 =NA(),2; row 5 0,4. Fill C2 =A2/B2 and this D formula through row 5:

=IF(ISNA(C2),"Await input",IF(ISERR(C2),"Investigate","Ready"))

C is expected to contain 4, a division error, #N/A, 0. D is Ready, Investigate, Await input, Ready. The ISNA reference explicitly describes propagation of an unavailable input through dependent arithmetic. That missing-value channel differs from a denominator that has been entered as zero.

In a copy, replace A4 with 8. C4 becomes 4, and D4 becomes Ready. The division failure on row 3 remains Investigate. Then change B3 to 5: C3 becomes 2, and every row is Ready. Keep the original sheet if you need to demonstrate both stages.

A two-branch formula such as =IF(ISERR(C4),"Investigate","Ready") would label the original missing result Ready. That formula implements the narrower predicate correctly, but its message is misleading. Use the three-state version when absence is a meaningful state.

ISERR is useful for triage, not for deciding that every non-#N/A failure is safe to ignore. A bad reference and a division by zero may require entirely different fixes. Preserve the failing source cells and inspect their actual error categories.

Do not infer native error tokens for untested malformed inputs from another spreadsheet. This guide uses only ordinary referenced results and the documented NA distinction. A range passed as one argument, direct arrays, imported specialized values and localized function names need separate target-version checks.

ISERROR is the broader predicate. ISNA handles the excluded category. IFNA can replace that category, but replacement discards information unless the original is retained elsewhere.

Record the PlanMaker version/build, edition, platform, language and workbook format. Recreate the original dataset, inspect the actual formulas and then apply the specified one-cell changes on a copy. Compare the original and changed outputs, not only a screenshot of the final values. Save/reopen and cross-product import results remain separate tests; neither was performed for this guide.