Convert Spreadsheets
Between Any Format
Convert spreadsheets between XLSX, XLS, CSV, TSV, ODS, JSON, and HTML. Fully private — your files never leave your device.
Upload spreadsheet(s)
Drag & drop or click to select
Accepted: XLSX,XLS,CSV,TSV,ODS,XLSB,FODS,TXT
What Is Excel Conversion?
Excel conversion is the process of changing a spreadsheet from one file format to another — for example, from XLS to XLSX, from CSV to Excel, or from a workbook to JSON or HTML. Different formats serve different needs: XLSX is the modern standard for Excel and many other tools; XLS is the legacy binary format; CSV and TSV are universal for data exchange; ODS is used by LibreOffice and others; JSON and HTML are common for web and APIs.
Converting between formats matters for compatibility, data portability, and legacy support. Older systems often produce or expect XLS or CSV. Newer apps and cloud services prefer XLSX or JSON. Databases and ETL pipelines frequently use CSV or TSV with specific delimiters. By converting with our online tool, you avoid installing software and keep your data on your device.
Our online Excel converter runs entirely on your device. You select one or more files, preview the data and choose a sheet if the workbook has several, pick the output format and any options (delimiter, headers, pretty print, all sheets or one), then click Convert & Download. The result is generated on your device and downloaded immediately. No upload means no privacy risk and no file size limits.
Use cases include migrating from legacy XLS to XLSX, preparing CSV or JSON for imports, publishing tables as HTML, batch-converting multiple files to the same format, and quickly viewing or re-exporting data from ODS or other spreadsheet formats. The tool is free, works on desktop and mobile, and requires no account or registration.
Discover Features
Wide format support, data preview, multi-sheet and batch conversion, and full privacy — all on your device
Wide Format Support
Convert between XLSX, XLS, CSV, TSV, ODS, JSON, and HTML. Upload from XLSX, XLS, CSV, TSV, ODS, XLSB, FODS, or TXT. All processing happens on your device with no server upload.
Data Preview
See your data in a table before converting. Preview the active sheet with sticky header and row/column counts so you know exactly what will be exported.
Multi-Sheet Support
Workbooks with multiple sheets are fully supported. Switch between sheets via tabs, preview each one, and choose to export all sheets or only the active sheet.
Batch Conversion
Upload multiple files at once. Each file appears in the list with its status; convert one or click Convert All to process every file to the same output format and options.
Privacy-First
Files are read and converted entirely on your device. Nothing is sent to any server. Your spreadsheets never leave your device — close the tab and nothing remains.
Instant Download
After conversion, the result downloads immediately. No waiting, no email required. You see a success message with the output file size so you can confirm the conversion.
How to Convert
Four steps: upload, preview and select sheet, choose format, convert and download
Upload your spreadsheet
Drag and drop one or more files onto the upload area, or click to browse. Supported input formats include XLSX, XLS, CSV, TSV, ODS, XLSB, FODS, and TXT. Multiple files can be added for batch conversion.
Preview data & select sheet
After parsing, view a table preview of the active sheet (first 50 rows). If the workbook has multiple sheets, use the tabs to switch between them. The active sheet is used for single-sheet export formats.
Choose output format
Select the target format from the grid: XLSX for modern Excel, XLS for legacy Excel, CSV or TSV for plain text, ODS for OpenDocument, JSON for data interchange, HTML for web tables, or TXT for plain text.
Convert & download
Optionally open Conversion options to set delimiter (CSV/TSV), JSON style, or whether to include all sheets. Click Convert & Download (or Convert All for multiple files). The converted file downloads immediately.
Free vs Paid — Excel Converter
Get started free, upgrade when you need more power.
Unlock the Full Power of Excel Converter
Remove daily limits, process larger files up to 500 MB, enable batch processing, and get priority support.
All Tools Bundle includes:
- All 60+ tools & 21 viewers included
- Unlimited daily uses
- 500 MB file size limit
- All advanced features
- Batch processing
- All export formats
- Priority email support
User Q&A
Real questions about Excel conversion and answers from the OnlinePCTools team
“I have an old .xls file from 2003 and need to open it in Google Sheets. What should I do?”
Priya Sharma
Data Analyst, Bangalore, India
Upload your .xls file here and choose XLSX as the output format. Convert & Download. The resulting .xlsx file is the modern Excel format that Google Sheets and most tools open without issues. Your file is converted entirely on your device, so it never leaves your computer.
— OnlinePCTools Team
“Can I export only one sheet from a workbook to CSV for a database import?”
James Wilson
Backend Developer, London, UK
Yes. Upload the workbook, click the tab for the sheet you want, then select CSV as the output format. In Conversion options you can set the delimiter (comma, semicolon, tab, or pipe) and whether to include headers. Click Convert & Download to get a single CSV file for that sheet.
— OnlinePCTools Team
“Are my financial spreadsheets sent to your servers? We have strict compliance requirements.”
Maria Santos
Finance Manager, São Paulo, Brazil
No. Conversion happens entirely on your device. Nothing is uploaded to our or any third-party server. For compliance, you can use the tool on an air-gapped machine if needed.
— OnlinePCTools Team
“I need to convert several CSV files to one Excel workbook with multiple sheets. Is that possible?”
Alex Chen
Research Assistant, Toronto, Canada
This tool converts from spreadsheets to one output format at a time. To get one workbook with multiple sheets from several CSVs, you would convert each CSV to XLSX and then combine them in Excel or another app, or use a script. Here you can batch-convert many files to the same format (e.g. all CSVs to XLSX) quickly.
— OnlinePCTools Team
Use Cases
Common scenarios where spreadsheet format conversion saves time and solves compatibility issues
Data Analysis
Convert XLS or ODS exports to XLSX or CSV for use in Python, R, or Excel. Get JSON for web apps or APIs. Preview data before converting to ensure the right sheet and structure.
CRM Import/Export
Export contacts or lists from CRM as XLSX or CSV, then convert to CSV with the correct delimiter (comma or semicolon) for import into another system or email campaigns.
Financial Reporting
Convert legacy XLS reports to XLSX for modern tools, or to CSV/TSV for data pipelines and reporting systems. Use multi-sheet export to keep all tabs in one workbook.
Legacy Migration
Move from old .xls or proprietary formats to XLSX or ODS for long-term archiving and compatibility with LibreOffice, Google Sheets, and Microsoft 365.
Web Publishing
Convert spreadsheets to HTML for embedding tables in websites or documentation. Export to JSON for web apps or static site generators.
Database Feeds
Export database results as CSV or XLSX, then convert to another delimiter or JSON for ETL, APIs, or data warehouses. Use batch conversion for multiple exports.
FAQ
Frequently asked questions about the Excel Converter
Q1. What formats can I convert?
Q2. Is my data safe?
Q3. Can I convert multiple sheets?
Q4. What's the max file size?
Q5. Will formulas be preserved?
Q6. CSV vs XLSX?
Q7. Can I convert to JSON?
Q8. Does it work on mobile?
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