Excel（.xlsx）をマークダウン表に変換する無料オンラインツール

Convert Excel (.xlsx / .xls / .csv) files to Markdown tables. Each sheet becomes a GFM pipe table. Runs entirely in your browser — safe for confidential data.

Excelファイル（.xlsx / .xls / .csv）をここにドロップ、またはクリックで選択

Supported formats: .xlsx ／ .xls ／ .csv ／複数ファイル選択可

ファイルはブラウザ内で処理されます

What the Excel to Markdown Converter can do

This free online tool converts Excel (.xlsx / .xls / .csv) files to Markdown tables entirely inside your browser. Your spreadsheet data is never uploaded, and each sheet is rendered as a GFM pipe table.

Supported Excel formats (.xlsx / .xls / .csv)

Supports .xlsx (Excel 2007+), .xls (Excel 97-2003), and .csv (comma-separated values). The format is auto-detected on upload.

Preserved after conversion: sheet structure, pipe tables, header rows

Each sheet name becomes an `##` heading and the rows are rendered as a GFM pipe table (`| col1 | col2 |`). The first row of each sheet is treated as the table header.

Not reflected in Markdown: merged cells, formulas, charts, images

Merged cells, charts, shapes, images, and formulas themselves cannot be expressed as Markdown tables and are dropped. Formulas are output as their calculated values.

Three steps to convert an Excel file to a Markdown table

Drag and drop your .xlsx file, or click to select one.
Press the "Convert to Markdown" button and check the per-sheet tables in the preview pane.
Copy to clipboard, or download the .md file.

Your Excel file is never sent to any server

How in-browser conversion works (SheetJS)

This tool uses the SheetJS (xlsx) library to parse the .xlsx directly in your browser and convert it to Markdown tables in JavaScript. No file content is ever sent to sakutto servers.

Why it's safe for confidential Excel data

Because nothing is transmitted, you can safely convert confidential spreadsheets such as sales data, customer lists, and HR records. Close the tab and no data remains.

Use cases for Excel to Markdown conversion

Pasting Excel tables into GitHub README files or issues while preserving the sheet structure.
Passing spreadsheet data to ChatGPT or Claude as a clean Markdown table to reduce token usage.
Importing tables into Obsidian or Notion as Markdown for your knowledge base.

Converting other formats to Markdown

Why Excel to Markdown Converter on sakutto is safe

Many online tools upload your files to external servers for processing. This tool never sends your Excel files (.xlsx / .xls / .csv) to any server — everything is processed entirely in your browser.

* Some AI-powered tools require server-side processing. Tools that send data to a server will always notify you beforehand.

Comparison	Typical online tools	sakutto
Where data is sent	Uploaded to external servers	Nowhere — processed in your browser
Data leak risk	Risk during transfer and server storage	No risk — no network transfer occurs
External traffic	File data travels over the internet	No file data appears in network logs
Offline use	Not possible (server required)	Works offline after initial load

How browser-based processing works

WebAssembly (WASM): Processes Excel files (.xlsx / .xls / .csv) in your browser at near-native speed. No server communication occurs.
Web Workers: Runs on a background thread separate from the main thread, so your browser stays responsive during processing.
After processing, your browser automatically frees the data from memory. No Excel files (.xlsx / .xls / .csv) remains outside your device.

For IT security teams: How to verify

You can verify that sakutto never sends your Excel files (.xlsx / .xls / .csv) externally by checking the Network tab in your browser's DevTools while using the tool. You'll see that no requests involving your Excel files (.xlsx / .xls / .csv) are made. This can also serve as documentation for your IT security team.

Frequently asked questions about the Excel to Markdown Converter

Can I convert .xls and .csv files too?

Yes. In addition to .xlsx, this tool supports .xls (Excel 97-2003) and .csv (comma-separated values). The format is auto-detected on upload.

How are multi-sheet Excel files converted?

Each sheet becomes a `## Sheet name` heading followed by a Markdown table. All sheets are placed in a single .md file in order, preserving the workbook structure.

Are formulas and merged cells preserved?

Formulas are output as their calculated values (the formulas themselves are not preserved). Merged cells go beyond what Markdown tables can express, so they are unmerged in the output.

Are my files stored anywhere?

No. All processing happens inside your browser. Neither the .xlsx file nor the Markdown output is sent to or stored on sakutto servers.