100% private — files never leave your device

Convert spreadsheets
instantly & privately

Drop an XLSX, CSV, or TSV file — pick your output format — download. No uploads, no sign-ups, no tracking. Everything runs in your browser.

Start Converting
XLS
report.xlsx
2.4 MB
Name
Date
Total
Alice
Jan 12
$340
Bob
Jan 15
$520
CSV
.csv
1.1 MB
TSV
.tsv
1.1 MB

Supported Formats

XLS

XLSX

Microsoft Excel workbook with full formatting support

CSV

CSV

Comma-separated values for universal compatibility

TSV

TSV

Tab-separated values for data with commas in fields

Three steps. Zero uploads.

Your file goes straight from your disk to the converter running in your browser. Nothing ever touches a server.

1

Drop your file

Drag and drop or browse. XLSX, CSV, and TSV up to 50 MB.

2

Pick your format

Choose your target format. Multi-sheet XLSX files get a sheet picker.

3

Download instantly

One click. Your converted file downloads immediately — no waiting.

Try it now

Free, private, and instant. No account needed.

1
Upload
2
Processor
3
Download
📄
Drop your file here or click to browse
XLSX, CSV, TSV · Max 50 MB
⇄

File Converter

Convert between XLSX, CSV, and TSV formats.

∖

Sheet Merger

Combine multiple spreadsheets into one.

Coming soon
▢

Row Filter

Filter and export rows matching your criteria.

Coming soon
📄

CSV

Comma-separated

📄

TSV

Tab-separated

📊

XLSX

Excel workbook

Converting your file…

✅

Conversion complete

Your files stay on your device

No server, no cloud, no third-party processing. The converter is a Web Worker that runs entirely in your browser's sandbox.

100% Client-Side

Everything runs in a Web Worker in your browser. Nothing is uploaded anywhere.

Instant Results

No server round-trips. Conversion starts the moment you click Download.

No Sign-Up Required

No account, no email, no cookies. Just convert and go.

Frequently Asked Questions

▸ How do I convert XLSX to CSV online?
Drop your XLSX file into the converter, choose CSV as the output format, and click Download. Everything runs in your browser — no upload required.
▸ Is it safe to convert spreadsheets online?
Yes. The converter runs entirely in your browser using a Web Worker. Your files are never sent to a server.
▸ What file formats are supported?
XLSX (Excel), CSV, and TSV. You can convert between any combination.
▸ Is there a file size limit?
50 MB. Processing happens locally, so speed depends on your device.
▸ Can I convert a multi-sheet XLSX file?
Yes. When you upload a multi-sheet XLSX, a sheet picker lets you choose which one to convert.
▸ Do I need to install anything?
No. Works in any modern browser — no extensions or plugins needed.

Need monitoring for your spreadsheets?

Downfor Sheets scans your Google Sheets for broken formulas, duplicates, and data quality issues — automatically.

Learn More