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FileConversion.co

Convert XLS to XLSX

Upload a file, confirm or change the source and target formats, then convert.

Drag & drop files here or browse. Max file size 100 MB for your account. Sign up or view pricing.

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Conversion results

Converted files are automatically deleted after 8 hours. Please download files before they are deleted.

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How your files are processed

Files are uploaded and processed on our servers, then made available for download.

What this tool does

Cell grids and formulas are read from XLS; values and formatting are emitted to XLSX, dropping features the sink format cannot represent.

Exports that flatten to plain text drop workbook-only objects; binary targets retain more sheet metadata.

  • XLS — Workbook formats carry sheet topology, cell types, and formula AST until export.
  • XLSX — Sink either preserves binary sheet features or flattens to row text only.
  • Locale — Decimal separators and date epochs reinterpret on import unless locale metadata travels with the file.

How to convert XLS to XLSX?

  1. Choose file — upload a XLS file that matches this page (allowed extensions apply).
  2. Convert to XLSX — lock the target format if needed, then start the job and wait for status updates.
  3. Download — grab the finished file from your job link before the retention window ends.

Why convert XLS to XLSX?

XLS may carry pivots and macros XLSX cannot round-trip; CSV trades structure for ingest speed into databases.

XLS might carry charts or macros XLSX cannot represent, so plan validation after conversion.

Typed binary workbooks catch formula errors early; plain CSV defers validation until import—choose based on whether downstream wants richness or frictionless piping.

Common reasons to convert XLS to XLSX

  • Load XLSX into Snowflake when nightly jobs expect XLSX but finance emails XLS.
  • Upload XLSX to BigQuery for dashboard SQL when extracts land as XLS.
  • Open XLSX in Google Sheets when budgets need comments trapped in XLS mail.
  • Open XLSX in Excel when vendor XLS breaks macros until columns match templates.
  • Import XLSX into Airtable when sync accepts only XLSX but partners send XLS.

Will converting XLS to XLSX affect quality or file size?

Plain values and headers usually survive into the next format.

Formulas, charts, and macros often flatten—spot-check totals and dates before production imports.

XLS vs XLSX

XLS (XLS)

XLS is classic Excel before 2007. Moving to XLSX aligns with modern Excel and cloud co-editing; CSV strips to values when BI tools forbid binaries.

XLSX (XLSX)

XLSX is Excel’s current workbook with sheets, formulas, charts, and tables. CSV flattens everything to plain rows for databases. ODS mirrors spreadsheets inside LibreOffice Calc.

XLS to XLSX decides whether Tableau, SAP imports, or finance analysts double-click the file successfully.

Troubleshooting

  • Delimiters: comma vs semicolon vs tab must match the importer; locale changes decimal separators.
  • Formulas: CSV stores values; complex formulas, pivots, and charts usually drop on flatten export.
  • Sheet scope: multi-sheet workbooks may export one sheet or split files—confirm which sheet feeds the pipeline.
  • Types: dates and long integers can import as text—set column types after import.
  • Upload fails or stalls: refresh the page, try a different browser, or disable strict content blockers for this session.

XLS to XLSX FAQ

Row and column counts matter more than extensions. Wide CSV files or deeply nested JSON can take longer to parse than tiny configs.

Yes. Upload a file, confirm the output format, run the job, and download the result from the status page.

Use the From/To menus on this converter or open another slug page if the pair you need is supported. Unsupported combinations will not appear as selectable options.

CSV flattens to values; complex formulas may disappear unless the target format supports them. XLSX↔ODS keeps more structure than CSV↔anything. Recompute critical totals after conversion.

XLSX opens in Excel and Google Sheets; CSV opens everywhere but loses formulas; ODS targets LibreOffice. Send XLSX that mirrors your recipient’s toolchain.