One JSON literal per line: A1=10, A2="text", A3=true or A4=null. At most 20 cells in A1:Z1000. Unspecified cells behave as blanks.
Choose a cell distinct from the supplied inputs.
Free local formula check
Check an Excel formula
Check a formula with explicit input cells. Get an actual local result; optional explanations are separate.
Excel formula checker
Enter → Check locally → Copy or open workbook.
Fictional inputs: A1=10, A2=20, A3=30. Result cell: B1.
Supported formulas use the same Rust workbook engine as our editor. Unsupported functions, references, cycles and resource limits report a validation failure. A successful calculation checks this case, not your business logic or complete Excel compatibility. No account or payment is required for local checks.
Explain or suggest a formula
Only your prompt and checked context items go to OpenRouter and the model provider selected by our server. Local checks need no provider. Optional assistance may be unavailable or rate limited. Suggestions are checked locally before you choose to use them.
Test a formula with the inputs you supply
Try a fictional SUM example, then replace its formula and literal input cells with your own test case. The result comes from the same local Rust workbook engine used by the editor.
How it works
- Enter the formula, a separate result-cell address and up to 20 explicit literal input cells.
- Choose Check formula to calculate locally and inspect a typed result or a clear validation failure.
- Copy the result or open the generated workbook in the existing editor. Optional explanations use only context you explicitly include.
Output and limitations
Calculation coverage is partial. Unspecified cells behave as blanks; external workbooks are not fetched. This tests supplied inputs, not intended business logic or complete Excel compatibility. Optional provider help can be limited or unavailable.
Keep a copy of your original workbook and review downloaded results before using them.
Frequently asked questions
Is the Excel formula checker free?
Local deterministic checks need no account or payment. Optional external assistance is separate and may be rate limited or unavailable.
Are my formulas sent to an AI service?
Local checks stay in this browser. Only the prompt and context items you explicitly select in Optional formula explanation go to OpenRouter and the model provider selected by our server.
Does a successful check prove my spreadsheet is correct?
No. It proves the supported local engine computed this formula with the supplied inputs. Review missing inputs, business rules and compatibility with your target spreadsheet application.
Can I open the result in a workbook?
Yes. Open generated workbook in editor passes the checked XLSX to the existing workbook editor without another upload. Formula expressions and calculated results are retained.
Is my workbook uploaded to a server?
The anonymous browser file tools process workbook contents locally. The website still makes ordinary requests for pages and sample files. Read the privacy page for details.
Which Excel files can I open?
Choose XLSX files with a combined size of 128 MiB or less. Legacy XLS files and password-protected or encrypted workbooks are not supported.
Related workbook tools
Prefer an assistant connection? Set up XLSX Formula Checker MCP.