Open CSV files too big for Excel.
Find the rows you need and take them back to Excel. Free, with no signup.
Works best in Chrome
When Excel says no
Microsoft ExcelThis data set is too large for the Excel grid. If you save this workbook, you'll lose data that wasn't loaded.
Excel stops at 1,048,576 rows. MegaCSV opens every row, however many there are, and shows them as rows and columns, with the true row number on every row.
Other messages it gets you past
- ExcelThis data set is too large for the Excel grid.
- ExcelFile not loaded completely.
- Excel for MacNo Power Pivot or Data Model, so no way past 1,048,576 rows.
- Google SheetsThis action would increase the number of cells above the limit of 10,000,000 cells.
- LibreOffice CalcThe maximum number of rows per sheet was exceeded.
- Notepad++File is too big to be opened by Notepad++.
- pandasMemoryError: Unable to allocate 51.0 GiB for an array.
Your rows on screen in a tenth of a second.
A 5 GB file with 48 million rows shows its first rows in 0.1 s and is read to the last row in 5.1 s, ready to scroll, search and filter. Excel stops at 1,048,576 rows, about 2% of that file.
Seconds until you see your data
Opening a 5 GB CSV. Scale is compressed so MegaCSV's bars are visible.
- MegaCSV0.1 s to the first rows
- MegaCSV, every row5.1 s to read all 48 million rows
- Cloud tools33 min just to upload 5 GB at 20 Mbps
Measured, not promised
| 1 GB | 5 GB | 20 GB | |
|---|---|---|---|
| Rows | 9,732,075 | 48,273,484 | 191,964,560 |
| First rows on screen | under 0.1 s | 0.1 s | under 0.1 s |
| Every row read and counted | 1.3 s | 5.1 s | 20.2 s |
| Find a word in every row | 2.1 s | 5.4 s | 24.0 s |
| Filter (country is IN) | 1.6 s | 8.9 s | 43.0 s |
| Export the filtered rows to CSV | 4.2 s | 19.3 s | 82.9 s |
| Open it again later | 0.1 s | 0.1 s | 0.1 s |
MacBook Air (M1, 8 GB RAM), Chrome, November 2026. Test files made up of order rows with 12 columns.
Three steps, no formulas
- Choose your file. Rows appear while the rest is still being read.
- Add a filter. vendor contains Acme
- Export to Excel. 12,408 rows fit in one sheet; bigger results are split for you.
Filter without formulas
Pick a column, a condition and a value. Add as many conditions as you need; a row shows when it meets all of them.
vendor contains Acme
amount is a number between 10,000 and 50,000
No formulas, no code. Export the matching rows to Excel; results bigger than one sheet are split for you.
Split it for an import
Parts of 1,048,575 rows for Excel, 50,000 for Salesforce or 25,000 for NetSuite, each with the header row. Quotes and line breaks inside cells stay intact.
Keep your values as they are
Leading zeros, long account numbers and dates stay exactly as written, in the grid and in the Excel file you export.
How it compares
| MegaCSV | Excel | Google Sheets | Power Query | |
|---|---|---|---|---|
| Rows | No limit | 1,048,576 | About 330,000 at 30 columns | No limit, but a preview only |
| Works on Mac | Yes | Yes | Yes | Partly; no Data Model |
| Filter without formulas | Yes, pick a column and a condition | Up to the row limit | Up to the cell limit | Menus and steps |
| Back to Excel | One click, split to fit | — | Download | Load to sheet, row limit applies |
| Price | Free | Microsoft 365 | Free | Included in Excel for Windows |
Excel gave up. Now what?
The same questions come up every day on Reddit and under YouTube tutorials. Here's what people said, and what MegaCSV does about it.
“Excel… just dumps the rest of the data.”
MegaCSV opens every row and shows the true count.
“Can I use an external program? No. That's my main issue.”
Nothing to install. It runs in the browser you already have.
“HOW DO WE DO IT ON A MAC”
Works in Safari, Chrome, Edge and Firefox on a Mac.
“I don't need probably 85% of it.”
Filter to the rows you need and export just those.
“How do you export the 10 million records to a csv file?”
Export to CSV or Excel in one step, split to fit if needed.
“I have to do this on a monthly basis!”
Files you've opened before open again instantly.
Who it's for
Anyone handed a CSV that Excel can't hold.
- Finance and audit
- General ledger dumps, bank and payment exports, monthly ERP extracts.
- IT and migrations
- Old database exports headed for a new system.
- Research and students
- Lab and survey data, public datasets, dissertation files, on Windows or Mac.
- Marketing and e-commerce
- Orders, ad reports, crawls and Search Console exports.
At a glance
- Largest file tested
- 20 GB, 192 million rows
- Row limit
- None
- Signup or install
- None
- Works best in
- Chrome
- Works on
- Windows, Mac, Linux, ChromeOS
- Price
- Free
Questions
How do I open a CSV file that's too big for Excel?
Open it in MegaCSV. Choose the file and every row appears in seconds, with no row limit. Find or filter the rows you need, then export them back to Excel.
What is the maximum number of rows in Excel?
1,048,576 rows per sheet (about 10.5 lakh), and 16,384 columns. Anything past that is cut off when Excel opens a CSV. MegaCSV has no row limit and splits exports so each part fits in one Excel sheet.
Why does Excel say “This data set is too large for the Excel grid”?
The file has more rows than one sheet can hold, so Excel loads only the first 1,048,576 and drops the rest. Open the whole file in MegaCSV, filter it down, and export a part that fits.
Can I open a large CSV file on a Mac?
Yes. MegaCSV runs in Safari, Chrome, Edge or Firefox on a Mac. You don't need Power Pivot or the Data Model, which Excel for Mac doesn't have.
Will it change my data?
No. Values show exactly as they are in the file: leading zeros, long account numbers and dates stay as written. Excel exports keep IDs and long numbers as text.
How do I split a large CSV into smaller files?
Open the file, choose Export, and pick a size: 1,048,575 rows to fit Excel, 50,000 for Salesforce imports, 25,000 for NetSuite, or your own number. Every part gets the header row.
Which browser works best?
Chrome. It saves exports straight to a folder you pick and remembers the files you've opened. Edge works the same way. Safari and Firefox open, filter and export files too; for files over 5 GB, use Chrome.
Do I need to install anything or sign up?
No. It works in your browser, so there's nothing to install and no account to create. That also means no IT ticket on a work laptop.
How big a file can it open?
Files of tens of gigabytes and hundreds of millions of rows. The practical limit depends on your computer; MegaCSV tells you if a file is larger than it can handle comfortably.
Is MegaCSV free?
Yes. Opening, finding, filtering and exporting are free, with no row limit and no trial period.
Open your file now.
Works best in Chrome