= Write My Formula

Excel #NUM! error fixer

Fix an Excel #NUM! error by checking the number Excel cannot use.

#NUM! means the formula handed Excel a numeric value it could not calculate with. Paste the formula, describe what the result should be, and get a repair path for formatted constants, iterative functions, invalid math inputs, and numbers outside Excel limits.

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Purpose-built inputs

A focused workflow for everyday spreadsheet work.

Structured formula builder

Task, table context, target range, and function hint keep the request specific.

Write / Explain / Fix modes

Generate a new formula, translate a pasted one, or diagnose common syntax issues.

Excel and Sheets toggle

Compatibility notes call out modern functions and platform-specific behavior.

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Common formulas

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Excel formula help

Get help writing, explaining, or fixing one Excel formula with range notes and checks before you paste.

AI Excel formula generator

Generate an Excel formula from plain English with range notes, an explanation, and checks before you paste.

Formula Bot alternative

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SheetSolver AI alternative

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Percentage formulas

Build percent of total, percent change, discount, markup, tax, tip, and completion-rate formulas.

Fix my Excel formula

Paste a broken formula and get a corrected version with checks for errors, text cells, ranges, and fallbacks.

Excel formulas not working

Fix formulas that stop calculating after imports, copied ranges, locale settings, or text-number mismatches.

Excel #VALUE! error

Repair formulas blocked by text values, hidden spaces, wrong argument types, dates, or subtraction syntax.

Excel #NAME? error

Fix formulas with misspelled functions, undefined names, missing quotes, or unsupported functions.

Excel #DIV/0! error

Fix formulas blocked by zero or blank denominators, ratio logic, averages, and IFERROR tradeoffs.

Excel #SPILL! error

Fix dynamic array formulas blocked by spill ranges, tables, merged cells, whole-column references, or changing array sizes.

Excel #NUM! error

Fix formulas blocked by invalid numeric values, formatted constants, non-converging IRR or RATE inputs, or numbers outside Excel limits.

Excel circular reference

Fix formulas that point back at their own result cell or need deliberate iterative-calculation checks.

Excel #REF! error

Repair formulas broken by deleted rows, moved cells, invalid references, or shifted lookup ranges.

VLOOKUP #N/A error

Fix lookup formulas that return #N/A because of exact-match settings, text-number mismatches, or range setup.

Date formulas

Create due dates, workday counts, month-end dates, date differences, and overdue checks.

FILTER formulas

Return matching rows for status, region, date, text, and threshold conditions.

Text formulas

Split, extract, join, trim, clean, and replace text from messy imported cells.

Data validation formulas

Block bad IDs, duplicate values, missing fields, and invalid entries with custom TRUE/FALSE rules.

XLOOKUP formulas

Return matching values with separate lookup and return ranges.

INDEX MATCH formulas

Build flexible lookup formulas for left lookups, two-way lookups, and older Excel files.

SUMIFS formulas

Total rows that match status, date, category, customer, or region rules.

Use case

Excel #NUM! error fixer for spreadsheet work.

Help Excel users fix one formula returning #NUM! by identifying whether the failure comes from invalid numeric arguments, formatted constants, iterative functions that cannot find a result, invalid math domains, or results too large or small for Excel.

What this page gives you

  • A focused fix pass for one formula returning #NUM!.
  • Checks for formatted constants, invalid numeric arguments, iterative-function convergence, impossible math inputs, and results outside Excel limits.
  • A revised formula direction you can test before hiding the numeric problem with a broad error fallback.

When to use it

Use this page when Excel returns #NUM! because the formula contains a number Excel cannot use, an iterative function such as IRR or RATE cannot find a result, or the calculation produces a value outside Excel limits. It is strongest when you can paste the formula and include the input values that drive the numeric result.

Do not use IFERROR as the first fix if the numeric problem affects the meaning of the result. A clean-looking fallback can hide a failed financial calculation, invalid input, or result-size problem that should be checked directly.

Worked example

An IRR formula can return #NUM! when the cash-flow pattern does not let Excel settle on a result within its iteration settings.

=IRR(B2:B12,0.1)

The formula supplies a starting guess for IRR, but the checks still tell you to confirm the cash flows contain the sign pattern needed for a meaningful rate before using the result.

Check before you paste

  • Remove currency symbols and thousands separators from constants typed directly inside formulas.
  • Check whether iterative functions such as IRR or RATE have inputs that can actually converge to a result.
  • Confirm the formula is not asking for invalid math, such as a square root of a negative number or a log of zero.
  • Restructure calculations that produce numbers outside Excel limits instead of only wrapping them in IFERROR.

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