How to open a CSV file that is too big for Excel
- Choose the file. Drop a CSV, TSV or TXT file of any size above. The encoding (UTF-8, Windows-1252, UTF-16…) and the delimiter (comma, semicolon, tab or pipe) are detected automatically.
- Scroll right away. The first rows appear in a second. While the rest of the file is indexed you see the progress and the row count growing.
- Search, filter or jump. Type a value to keep only the matching rows, in one column or in all of them, or go straight to row 3,500,000.
- Export what you need. Download the filtered rows as CSV, or as Excel files of up to 1,048,576 rows each, ready to open in Excel.
Private by design: nothing is uploaded
The file is read by your own browser, a few megabytes at a time. It is never sent to a server, so a 3 GB export with customer data, logs or transactions stays on your computer. The page only downloads its own code and, if you open or export Excel files, open-source spreadsheet libraries from this same site.
You can check it in the Network tab of your browser's developer tools, or disconnect from the internet after the page loads and keep working.
Why Excel cannot open your CSV
An Excel worksheet holds at most 1,048,576 rows and 16,384 columns. When a CSV has more lines, Excel warns that the file was not loaded completely and silently drops everything after row 1,048,576. Large files also use a lot of memory: the 32-bit versions of Excel can run out of it well before the row limit, and Excel can change your data on the way in by removing leading zeros, turning long IDs into scientific notation and converting text that looks like a date.
This viewer never builds a spreadsheet in memory. It scans the file once to remember where every 128th row starts (taking line breaks inside quoted fields into account) and then reads only the rows on screen. That is why it can open CSV files with tens of millions of rows and several gigabytes, and it shows every value exactly as it is written in the file.
What you can do with it
- Look inside a huge exportDatabase dumps, CRM and e-commerce exports, server logs, bank or analytics data with millions of lines.
- Count rows and columnsKnow the exact number of records before importing, and spot rows with a different number of columns.
- Find and filter recordsKeep the rows where a column contains, equals or starts with a value, or where a number is above or below a threshold.
- Split a CSV for ExcelExport to .xlsx files of up to 1,048,576 rows, each with the header row, frozen and with filters.
- Check a columnEmpty and filled cells, distinct values, minimum, maximum and average of numbers, most frequent values.
- Fix the encodingSwitch between UTF-8, Windows-1252, UTF-16 and other encodings if accents look wrong, and export as UTF-8.
Other ways to work with a CSV over a million rows
- Power Query and the Data Model in Excel (Data › From Text/CSV › Load To… › Only Create Connection, with “Add this data to the Data Model”) can summarize more than 1,048,576 rows in a PivotTable, but you cannot see or edit them as a sheet.
- Splitting the file into chunks below the limit works with any tool, including the export of this page.
- Command line and code:
wc -l counts lines (not rows, if fields contain line breaks), and Python with pandas or DuckDB can query large files if you are comfortable writing code.
Known limitations
- Sorting the whole multi-gigabyte file is not supported. Sorting works on up to 1,000,000 rows that fit in memory, so filter first and then sort the result.
- It is a viewer: cells cannot be edited in the page. Filter and export, then edit the result in Excel.
- Excel files (.xlsx, .xls, .ods) are read completely into memory with SheetJS, so their practical limit is your device's memory (roughly a few hundred thousand rows on a phone). CSV files have no such limit.
- Searching reads the whole file, so on a 5 GB file a search takes as long as reading 5 GB from disk. You can cancel it and keep the matches found so far.
- Each Excel file exported has at most 1,048,576 rows and 16,384 columns, and cells are cut at 32,767 characters, which are Excel's own limits. Values are exported as text or plain numbers, without formatting.
- Very large exports are created in your browser's temporary storage before downloading; make sure the disk has enough free space.