Spreadsheet Converter
Upload any spreadsheet and convert it to XLSX, CSV, TSV, ODS, or JSON instantly. All processing happens in your browser — your files never leave your device.
Drop a spreadsheet here or browse
XLSX · XLS · CSV · ODS · TSV
About Spreadsheet Converter
Spreadsheet data rarely stays in one format. Data exported from a CRM arrives as CSV. An accountant sends an Excel XLSX file. LibreOffice users work in ODS. JavaScript applications need JSON arrays. Moving between these formats without the right tool means either opening heavyweight spreadsheet software or relying on server-based converters that upload your financial, client, or business data to unknown services.
Our Spreadsheet Converter uses SheetJS — the industry-standard JavaScript library for spreadsheet parsing and generation — to read XLSX, XLS, CSV, TSV and ODS files and write them back out as XLSX, CSV, TSV, ODS or JSON. After uploading a file, the tool displays a table preview of the first 20 rows, along with the total row and column count, so you can confirm the content before converting. The first sheet in the workbook is the one converted: if your file has several sheets, move the one you need into first position before uploading.
A sample product table is loaded the moment the page opens, so you can try every output format before committing your own data — and the "Load demo" link brings it back at any point. Conversion is value-based: cell contents come across intact, while formatting, charts and merged-cell layouts are not carried into the output.
The JSON output uses the first row as property names, producing an array of objects that can be fed directly into a REST API, database seeding script, or JavaScript application. The TSV format is useful when your data contains commas inside cell values (addresses, descriptions, names with initials) since tab-separated values avoid the CSV quoting complexity.
How to Use Spreadsheet Converter
- 1Drop a spreadsheet onto the upload area or click to browse — XLSX, XLS, CSV, TSV and ODS are accepted.
- 2Preview the data table to confirm the content and column structure is correct — the header row and the first 20 rows are shown.
- 3Check the row and column count beside the filename to confirm the whole file was parsed.
- 4Pick the output format in the "Convert to" row — XLSX, CSV, TSV, ODS or JSON.
- 5Click "Convert & Download" — the file is generated and saved in a single step.
- 6Click "Load demo" at any time to swap your file for the built-in sample table.
Use Cases
- →Convert Excel XLSX exports to CSV for data pipeline and ETL workflow processing
- →Export spreadsheet data as JSON for consumption by a REST API or JavaScript application
- →Open LibreOffice ODS files and convert them to Excel-compatible XLSX format
- →Transform CSV exports from databases or analytics tools into structured JSON objects
- →Convert a legacy XLS file from an old system into modern XLSX or plain CSV
- →Change TSV files to CSV for compatibility with tools that only accept comma-separated input
Tips
- ✓The first row is used as property names when exporting to JSON — keep column headers clear and descriptive
- ✓TSV is ideal for data containing commas in cell values (addresses, product names with commas)
- ✓Large files with thousands of rows may take a few seconds to process in the browser
- ✓When converting to JSON, nested data from merged cells may need manual restructuring afterward
- ✓Use the demo file to explore the tool's behavior before uploading your own data
- ✓The first sheet is the one converted — reorder your sheets before uploading if you need a different one
- ✓JSON is an output format only; to bring JSON data in, use our Data Converter instead
- ✓XLS is accepted as input, but the output list writes the modern XLSX instead of the legacy format
- ✓The preview caps at 20 rows for speed — the full file is still converted, however many rows it has
- ✓The whole file is held in your browser's memory, so very large workbooks depend on your device rather than a server limit
- ✓Conversion carries cell values, not styling — colours, fonts, column widths and charts do not survive the trip
- ✓A file that cannot be parsed, because it is corrupted or password-protected, raises an on-screen message rather than downloading a broken file
Frequently Asked Questions
You can upload files in XLSX, XLS, CSV, ODS, and TSV formats. Output formats include XLSX (Excel), CSV, TSV, ODS (LibreOffice), and JSON.
When you choose JSON as the output format, the converter uses the first row of the spreadsheet as the property names (keys) for each object. Every subsequent row becomes one object in the resulting array.
No — all conversion happens entirely in your browser using SheetJS. Your file is never sent to any server.
If the file cannot be parsed — because it is corrupted, password-protected, or in a format the tool does not support — an error message appears.
The first sheet in the workbook. If your file has several sheets, move the one you need to the first position in Excel or LibreOffice before uploading. The preview table always shows the sheet that will be converted, so you can confirm before downloading.
There is no enforced limit, but the entire file is held in your browser's memory while it is parsed. Files in the tens of megabytes normally convert fine; much larger workbooks can get slow or run out of memory depending on your device.
CSV (Comma-Separated Values) uses a comma to separate fields, while TSV (Tab-Separated Values) uses a tab character. TSV is often preferred when data contains commas.