ISERROR Function in Excel

What this does

ISERROR returns TRUE for every error type: #N/A, #VALUE!, #REF!, #DIV/0!, #NAME?, #NUM! and #NULL!. Its close relative ISERR does the same but excludes #N/A, which is often what you actually want. The warning that belongs on this function is that blanket error suppression hides real bugs — a formula wrapped in ISERROR keeps working after someone deletes the column it referenced, silently returning a fallback instead of the #REF! that would have told you. Prefer the narrower test whenever you can name the error you expect. Keep the inputs visible and clearly labelled and the whole thing stays auditable — anyone who opens the file later, including you, can see at a glance exactly what feeds the result and change one assumption without hunting through the formula. The difference between a quick fix and a sheet you can trust is the extra minute you spend validating “iserror function in excel”. Start on a copy or a tiny sample, keep the affected formula visible, and compare the result with the tool above before you touch the real workbook. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. The point is a calculation you can defend to a CFO or an auditor, but the practical win is that someone else can open the file and understand what happened without asking you.

A worked example

Counting how many rows in a calculated column are broken: =SUMPRODUCT(--ISERROR(D2:D500)) gives a data-quality figure worth watching. Distinguishing the two cases explicitly: =IF(ISNA(lookup), "not found", IF(ISERROR(lookup), "formula error", lookup)) handles each on its own terms. ISERROR is the broadest error test, and knowing when NOT to use it is what keeps a workbook debuggable. A practical tip before you scale it up: build it once on a small block of test data, confirm the number against the tool on this page, and only then point it at your real sheet. That one habit catches almost every mistake while it is still cheap to fix, long before a wrong figure reaches a report or a colleague.

In Google Sheets

Google Sheets handles this almost identically to Excel. The formula syntax above is the same, and the menu lives under a slightly different label rather than a ribbon tab. Use the platform toggle at the top of the page to switch every keyboard shortcut between Windows and Mac, and expect at most cosmetic differences in naming. Nothing on this page is behind a login: the tool runs entirely in your browser, the formula is shown in full with one-click copy, and the steps work the same on Windows and Mac. That is the whole promise here — the exact answer, a way to prove it on your own numbers, and just enough context to make it stick. Here is the takeaway for “iserror function in excel”: copy the answer if you are busy, but if you have a spare few minutes, rebuild the example in Excel yourself with the tool above open beside it. That single pass — type it, run it, watch the result move when you change an input — is what turns a formula you found into a technique you trust. Keep your inputs labelled and referenced, never hard-coded, and the same sheet stays correct and auditable as it grows. Done that way, you will not need to look this up again, and you will be the person others ask.

Common mistakes

• Blanket-wrapping every formula, which hides #REF! and #NAME? faults that should be fixed rather than suppressed.
• Using ISERROR where ISNA was meant, so a legitimate "not found" and a genuine bug get the same treatment.
• Writing =IF(ISERROR(x), fallback, x), which evaluates x twice — IFERROR does it once.

Frequently asked questions