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XLSX to CSV Converter — Free, Local, No Upload

The short answer: An .xlsx workbook stores data as a ZIP of XML parts that only spreadsheet apps read reliably. Converting XLSX to CSV flattens one sheet into a single plain-text table with a header row, so any tool — from a data pipeline to a text editor — can consume it. Choose the separator and optionally add a UTF-8 BOM (EF BB BF) at the start of the CSV. Check how the target application decodes the text.

How to convert XLSX to CSV

Convert XLSX to CSV now

The button opens the Excel Converter with XLSX → CSV preselected — it runs entirely in your browser and nothing is uploaded.

Open Excel Converter

Local in your browser — nothing is uploaded

  1. Open the converter

    The button above opens the Excel Converter with the CSV output already selected.

  2. Drop your XLSX file

    Add the file (up to 50.0 MiB); .xlsx workbooks are read sheet by sheet and CSV files are parsed with explicit quoting rules.

  3. Convert and download

    Press Convert to process the workbook in a dedicated worker. When the result appears, press Download to save it. Cancel stops an in-progress run.

Conversion facts

Input format
XLSX
Output format
CSV
Max file size
50.0 MiB
Max dimensions
Worksheet XML ≤ 200.0 MiB · Output ≤ 32.0 MiB · ≤ 256 columns
Quality
Value-level — formulas use cached values, styles dropped
Processing
Local in your browser — nothing is uploaded

XLSX

XLSX → CSV

What to watch

Only cell values survive: formulas contribute their cached value (never recalculated), styles, merged cells and column widths are dropped, and dates become ISO strings. One sheet converts per run — pick it from the sheet list. Input is capped at 50 MiB (the ZIP may expand to 200 MiB of worksheet XML) and output at 32 MiB; wider files should be split before converting.

Keep converting

Related conversions

Continue with Toolars

  • The tool behind this page

    Excel Converter

    Convert .xlsx workbooks to CSV or JSON, or CSV back to .xlsx, entirely in the browser — values only, with an optional UTF-8 BOM marker (EF BB BF) for CSV. Check decoding in your target app. Inputs up to 50 MiB, outputs up to 32 MiB.

  • Not sure which tool fits the job?

    Structured Data Converter

    CSV ⇄ JSON already lives there — this pair page deliberately does not duplicate it.

Frequently asked questions

What exactly survives the conversion?
Only cell values. Formulas contribute the value cached by the app that saved the file — they are never recalculated — and styles, merged cells, and column widths are dropped. Date cells become ISO strings like 2026-09-20.
Why is there a UTF-8 BOM option?
The UTF-8 BOM option adds the bytes EF BB BF at the start of the CSV. Toolars writes that marker, but does not verify how your version of Excel or another target app decodes the file. Check the imported text there.
What are the file limits?
Inputs up to 50.0 MiB are converted locally in your browser (a .xlsx ZIP may expand to 200 MiB of worksheet XML), and outputs are capped at 32 MiB with at most 256 columns. Anything past a limit is refused with a clear message instead of being silently truncated.