Excel (XLSX) to CSV, JSON & Markdown
Most "convert XLSX online" services want you to upload the spreadsheet first, which is exactly what you cannot do with a payroll export, a customer list or anything else under an NDA. This tool unzips the workbook in your own browser — an .xlsx is a ZIP of XML parts — reads the shared string table and the cell styles, and hands back the sheet as text. Every sheet in the workbook is listed with its row count, so you can pick the one you need. Dates are the part everyone gets wrong: Excel stores them as a day count from 1899-12-30 (the 1900 leap-year bug included) and only the cell's number format says whether 45000 means a quantity or a date, so the format is read and genuine dates come out as ISO 8601 instead of five-digit numbers. Formula cells export their last calculated value, booleans become TRUE and FALSE, and empty cells keep their column position so rows stay aligned. Output as CSV with the delimiter your locale expects, as JSON keyed by the header row, or as a Markdown table to paste into a README.
How to use
- Drop an .xlsx or .xlsm file, or click to choose one.
- Pick the sheet you want — the row count is shown next to each name.
- Choose the output: CSV, JSON, or a Markdown table.
- Say whether the first row is a header; JSON uses it for the keys.
- Copy the result, or download it as a file.
Frequently asked questions
- Is my spreadsheet uploaded anywhere?
- No. The workbook is unzipped and parsed in your browser with fflate and the built-in XML parser. Nothing is sent to a server, and closing the tab discards it.
- Why do my dates come out as numbers in other converters?
- Because Excel stores a date as a serial number — days since 1899-12-30 — and only the cell's number format marks it as a date. A converter that ignores the style table sees 45000, not 2023-03-15. This one reads the format and writes ISO dates.
- What about formulas?
- Excel caches the last calculated value of every formula in the file, and that is what you get. The formula itself is not re-evaluated, so a workbook saved with stale results exports those results.
- Which files are supported?
- .xlsx and .xlsm — the ZIP-based formats Excel has used since 2007. The old binary .xls is a different format and is not supported; open it in Excel or LibreOffice once and save as .xlsx.
- Can it handle a password-protected workbook?
- No. An encrypted .xlsx is not a readable ZIP, so it fails to open. Remove the password in Excel first.
- Why semicolons instead of commas?
- Locales that use a comma as the decimal separator (most of Europe) expect a semicolon between fields, and Excel opens such files correctly. Pick whichever your spreadsheet program expects.
Guides on this topic
Related tools
CSV to Excel (XLSX) Converter
Turn CSV or TSV into a real .xlsx file in your browser, with leading zeros, long IDs and codes like SEPT1 kept exactly as typed.
CSV Viewer & Sorter
View CSV / TSV data as a sortable, searchable table — open a file or paste rows, no spreadsheet required.
CSV → HTML / Markdown / JSON Table
Convert CSV to an HTML `<table>`, a Markdown table, or a JSON array of objects — auto-detects the delimiter.
CSV ↔ JSON Converter
Convert CSV to JSON and JSON back to CSV, with a delimiter option.
Markdown Table to CSV Converter
Convert a GitHub-flavored Markdown table into CSV, TSV or semicolon-separated rows, in your browser.
Markdown Table Generator
Paste CSV, TSV, or pipe-delimited data and get a properly aligned GitHub-flavored Markdown table.