Open, chart and convert huge CSV & Excel files — privately in your browser.
Millions of rows. Nothing uploaded. Free.
Instant row counter
Count the lines in a CSV, TSV or TXT file of any size.
Drag and drop a file here
CSV, TSV or TXT, any size. Millions of lines are fine.
Your file never leaves your device. It is read by your browser in a background thread. Nothing is uploaded.
Curious how lines differ from records, or how to count rows from the command line? See the CSV row counter guide.
What works today, and what’s coming next
MegaRows is being built one tool at a time. Every tool follows the same rules: nothing to install, nothing uploaded and no artificial row limits.
Instant row counter
Available nowDrop a CSV, TSV or TXT file to see how many lines it has, which delimiter it uses and how many columns it has. The file is streamed through a background thread, so even a 10-million-line export is counted in under a second on a recent laptop.
Open the CSV row counterComing soon
Large CSV viewer
Open CSV files with millions of rows, then scroll, sort and search them, far beyond the 1,048,576-row limit of spreadsheet apps.
Charts with statistics
Plot any column in seconds, zoom into millions of points and see min, max, mean and more at a glance.
Convert CSV, Excel, JSON and PDF
Turn CSV into Excel, Excel into CSV, JSON into a table, or a table into a clean PDF, all in your browser.
Split, merge and compare
Split a giant file into smaller parts, merge many files into one, or compare two versions side by side.
Handles messy data
Detects separators, decimal commas and date formats automatically, and copes with quotes, blanks and odd rows.
Missing something?
Built for CSV files that are too big for Excel
Excel stops at 1,048,576 rows per sheet. Open a bigger CSV and it loads the first million or so rows, shows a warning that is easy to miss and leaves the rest behind. Save the file again and those rows are gone for good. Google Sheets has its own ceiling of 10 million cells per spreadsheet, which a wide export can hit long before a million rows.
Exports from databases, data loggers and analytics tools regularly run to tens of millions of lines. MegaRows is designed for exactly these files: it reads them in small chunks instead of loading everything into memory, so your device sets the limit, not an arbitrary cap.
Private by design: nothing is uploaded
Most online CSV tools upload your file to a server, process it there and send the result back. That is slow for big files, and it leaves a copy of your data on someone else’s computer: a real problem for customer lists, financial exports or anything covered by an NDA.
MegaRows works the other way round. Your browser reads the file straight from your disk, and the heavy lifting happens in a background thread (a Web Worker) on your own device. No server ever sees your data; the only thing ours receives is a message you choose to send through the feedback form.
You do not have to take our word for it. Open your browser’s developer tools, switch to the Network tab and count a file: no request carries your data. Our privacy statement explains the rest in plain English.
Typical online tools
- Row limits, often just 1,000 rows or a few megabytes
- Your file is uploaded to someone else’s server
- Dated, cluttered interfaces full of ads
MegaRows
- Millions of rows, limited only by your device
- Files are read locally and never uploaded
- A clean, modern interface with light and dark mode
Frequently asked questions
Is MegaRows free?
Yes. Everything available today is free to use and needs no account. Your files are processed on your own device, not on our servers, so a big file costs us nothing extra.
Are my files uploaded?
No. Files are opened and processed entirely inside your browser, in background threads (Web Workers). They are never sent to a server. You can check this yourself in your browser’s developer tools, in the Network tab.
How big can a CSV file be?
There is no fixed limit. Files are read in small chunks instead of all at once, so the practical limit is your device. We test with a 10-million-line CSV of over 400 MB, which the row counter handles in under a second on a recent laptop.
Which file formats are supported?
Today the row counter reads CSV, TSV and TXT files with comma, semicolon, tab or pipe separators. Excel (.xlsx) import and export, JSON conversion and PDF export are coming soon.
Can MegaRows open a CSV with more than 1,048,576 rows?
The row counter can already tell you exactly how many lines such a file has. The viewer, which will let you scroll, sort and search files far beyond Excel’s 1,048,576-row limit, is coming soon. Until then, our guide to opening CSV files that are too big for Excel explains the options that work today.
When will the viewer, charts and converters be available?
They are being built now and will launch here soon, but we would rather not promise a date we might miss. Tell us what you need through the feedback button: it shapes what ships first.
Do I need to install anything or create an account?
No. MegaRows runs in modern browsers such as Chrome, Edge, Firefox and Safari, on Windows, macOS and Linux. There is nothing to install and no account to create.