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#NUM!

Excel #NUM! Error Applies to: Windows 7, Windows 10, Windows 11

What it means

A formula produced a number too large or small for Excel to represent, or received an invalid argument.

Also seen as: #NUM!

Quick fix steps

  1. Check for impossible operations, like SQRT() of a negative number.
  2. If using an iterative formula, check File > Options > Formulas > Enable iterative calculation is configured correctly.
  3. Break a complex formula into smaller steps in helper cells to find exactly which part produces the invalid number.
For the full step-by-step walkthrough, see Understanding Excel Formula Errors (#REF!, #VALUE!, and More).

Frequently Asked Questions

Does #NUM! mean I typed a letter where Excel expected a number?
That would usually trigger #VALUE! instead — #NUM! specifically means the calculation produced a number Excel can't represent or handle, like an impossibly large result or an invalid input to a math function.
Is this related to Excel's maximum number size?
It can be — Excel has upper limits on the numbers it can display and calculate, and a formula that exceeds those limits (through exponential growth, for instance) will show #NUM!.

Other error codes

#REF! — #REF! Error

A formula is pointing to a cell that no longer exists — usually because a row, column, or sheet it referenced was deleted.

#VALUE! — #VALUE! Error

The formula received the wrong type of data — commonly text where it expected a number.

#DIV/0! — #DIV/0! Error

The formula is dividing by zero or by an empty cell.

#N/A — #N/A Error

A lookup formula (VLOOKUP, MATCH, XLOOKUP, INDEX/MATCH) couldn't find a matching value.