Free Spreadsheet Converter for Excel, ODS and CSV: No Sign-up, No Upload
This spreadsheet converter is free, needs no sign-up or login, and your files never leave your browser. Nothing is uploaded, no watermark is added, and there is no account to create. Drop in an Excel workbook, an OpenDocument sheet or a plain CSV, pick the format you want, and save the result from your own device.
Spreadsheets often hold the numbers you least want to send to a stranger: payroll, customer lists, invoices, grades. Because the conversion runs inside the page, the workbook is read and rewritten on your device and no copy exists anywhere else. Every spreadsheet conversion here uses the built-in sheet engine, so none of them needs an extra engine download.
You can convert between Excel formats (XLSX, XLSB, XLS), OpenDocument (ODS and the single-file FODS), delimited text (CSV, TSV) and older interchange formats such as DBF, SYLK and DIF. You can also export a sheet as an HTML table, JSON, a Markdown table, SQL INSERT statements or a PDF. Add many files at once and download them together as a ZIP.
- Free
- No sign-up
- Never uploaded
- No watermark
Your files are converted on your device and never uploaded.
How to convert
- Add your spreadsheets by dragging them onto the page or by using the file picker.
- Check the detected format of each file; it is read from the file content, not only the extension.
- Choose the target format, for example XLSX, CSV, ODS, JSON or PDF.
- Adjust the options that appear for that format, such as the delimiter for CSV or TSV.
- Press Convert and wait for each file to finish.
- Download a single result directly, or download a batch together as one ZIP.
Features
- Reads XLSX, XLSM, XLSB, XLS, ODS, FODS, Apple Numbers, CSV, TSV, DBF, SYLK, DIF and PRN.
- Writes XLSX, XLSB, XLS, ODS, FODS, CSV, TSV, TXT, DBF, SYLK, DIF, HTML, JSON, Markdown table, SQL and PDF.
- Runs in your browser with no upload, no sign-up and no watermark.
- No engine download is needed for any spreadsheet pair.
- Batch conversion with one ZIP download.
- Format detection by file content, so a renamed file is still recognised.
- Options for each target, such as the CSV and TSV separators.
- CSV and TSV can also become JSON Lines, YAML, XML, a Markdown table or SQL.
Supported formats
| Format | Read | Write | Notes |
|---|---|---|---|
| HTML.html | Yes | Yes | The markup language of web pages. |
| Plain text (TXT).txt | Yes | Yes | Unformatted text with no styles, images or layout. |
| Excel (XLSX).xlsx | Yes | Yes | The default Excel format since 2007. |
| Excel macro-enabled (XLSM).xlsm | Yes | No | XLSM can be read but not created because macros cannot be generated; convert it to XLSX. |
| Excel binary (XLSB).xlsb | Yes | Yes | Excel’s binary workbook format: opens and saves faster on very large files. |
| Excel 97-2003 (XLS).xls | Yes | Yes | The Excel format used until 2003. |
| OpenDocument Spreadsheet (ODS).ods | Yes | Yes | The spreadsheet format of LibreOffice Calc and OpenOffice. |
| Flat ODS (FODS).fods | Yes | Yes | OpenDocument spreadsheet stored as one plain XML file instead of a ZIP. |
| Apple Numbers.numbers | Yes | No | Numbers is Apple’s proprietary format, so it can be read but not created; convert it to XLSX or CSV. |
| CSV.csv | Yes | Yes | Comma-separated values: one row per line, plain text with no formatting. |
| TSV.tsv | Yes | Yes | Tab-separated values: like CSV but split on tabs. |
| dBase (DBF).dbf | Yes | Yes | The table format of dBase, also used by shapefiles and old accounting software. |
| SYLK.sylk | Yes | Yes | Symbolic Link: a text spreadsheet interchange format from Microsoft Multiplan. |
| DIF.dif | Yes | Yes | Data Interchange Format, created for VisiCalc in 1979. |
| PRN.prn | Yes | No | PRN is a printer-style text export that is read only here; convert it to CSV. |
| JSON.json | Yes | Yes | JavaScript Object Notation: the usual format for web APIs. |
| Markdown table.md | No | Yes | A table written with pipes and dashes, rendered by GitHub and most Markdown tools. |
| SQL INSERT.sql | No | Yes | A script of INSERT statements that loads the rows into a database table. |
About the formats
Excel formats: XLSX, XLSM, XLSB and XLS
XLSX is the default Excel format since 2007: a ZIP of XML files that holds multiple sheets, formulas and charts. XLS is the older Excel 97-2003 format and is limited to 65,536 rows per sheet, so a long table converted to XLS may not fit. XLSB is Excel binary, which opens and saves faster on very large workbooks but is less common outside Excel.
XLSM is an XLSX workbook that can carry VBA macros. It can be read here but not created, because macros cannot be generated. When you convert an XLSM, only the cell data is read; macros are not run and are not kept. If you need to keep macros, use Excel itself.
OpenDocument and Apple Numbers
ODS is the spreadsheet format of LibreOffice Calc and OpenOffice, an open ISO standard. FODS stores the same content as one plain XML file instead of a ZIP, which makes it easy to compare in version control or process with a script.
Apple Numbers files can be read and converted to XLSX or CSV, but Numbers is a proprietary format and cannot be created here. PRN, the space-aligned text a spreadsheet writes when you print to file, is read only: convert it to CSV.
CSV, TSV and plain text
CSV is one row per line, values separated by commas, with no formatting at all. It opens in every spreadsheet and database tool. TSV is the same idea split on tabs, which is safer when the data itself contains commas. Neither format stores formulas, colours, column widths or more than one sheet.
Converting a workbook to CSV, TSV, TXT or JSON exports only the first sheet, and formulas become their calculated values. If you need every sheet, convert each one to its own file first or choose a workbook format such as XLSX or ODS.
Older interchange formats: DBF, SYLK and DIF
DBF is the table format of dBase, still used by shapefiles and some accounting software; its field names are limited to 10 characters. SYLK is a text interchange format from Microsoft Multiplan. DIF, the Data Interchange Format, was created for VisiCalc in 1979. You are unlikely to choose these for new work, but they are handy when an old program insists on them.
Spreadsheet to JSON, Markdown, SQL, HTML and PDF
Exporting to JSON gives you rows as records, ready for a script or an API. A Markdown table is written with pipes and dashes and renders on GitHub and most Markdown tools. SQL produces a script of INSERT statements that loads the rows into a database table. HTML writes a plain table that opens in any browser.
PDF prints cell values only. Charts, images and cell styling are dropped, so treat it as a simple printout rather than a copy of how the sheet looked in Excel. HTML pages can also go the other way: tables in a web page become rows and columns in XLSX, CSV or JSON.
Privacy: how it works
- Your spreadsheets stay on your device. The page reads each file with the browser's file API, converts it with code running in the tab, and hands the result back as a download. No upload happens, so there is no copy of your file on our servers to protect, delete or leak.
- There is nothing to sign up for and no login. The converter does not ask for an email address, and it does not need to know who you are to do its job.
- You can check the claim yourself: open your browser developer tools, watch the Network tab while a file converts, and you will see no request that carries your file.
- A workbook can carry more than the visible cells: hidden sheets, comments and personal names in the file properties. Since the file is never uploaded, none of that leaves your device, but remember it travels with the converted file when you share it yourself.
Tips
- Check the first row: CSV and JSON exports treat it as the column names, so put your headers there.
- Convert to XLSX rather than XLS unless an old program requires it, because XLS stops at 65,536 rows.
- If a CSV opens with broken accents, the problem is usually the text encoding in the program that opens it, not the file.
- Use TSV instead of CSV when your cells contain commas, such as addresses.
- Split a multi-sheet workbook into one file per sheet before exporting to CSV, since only the first sheet is exported.
- Remember that formulas become plain values in CSV, TSV, TXT and JSON, so keep the original workbook.
- For SQL and JSON output, make sure every row has the same columns so each record has the same fields.
- Keep dates as real date cells, and check a few of them in the output because each format writes dates its own way.
- Convert a few rows first when you are unsure about an option, then run the whole batch.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial, no credit card and no watermark added to your results. Ulkaa Tool does the conversion with your own device, so there is no server bill to pass on to you.
Are my files uploaded?
No. Your spreadsheets are read and converted inside your browser and are never sent to Ulkaa or to anyone else. The result is created on your device and you save it from there.
Do I need an account?
No. There is no sign-up and no login. Open the page, add your files and convert. An Ulkaa account is not needed for anything on this tool.
Is there a file size limit?
No limit is set by us. The real limit is your device: the conversion uses your own memory and processor, so very large files can be slow, and a very big batch may need to be split into smaller runs.
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