Frequently asked questions

No. The file is read and parsed entirely inside your browser using a Web Worker. openbigcsv.com does not upload, store, or log the contents of your file.

The page itself needs to load once from the internet, but once loaded, parsing a file does not require a network request — your file never goes anywhere.

The free browser tool is designed for up to about 300,000 rows in a single tab, depending on your device's available memory and the number of columns. For files in the tens of millions of rows and beyond, use Row Zero, which is free to start and connects directly to data warehouses.

CSV, TSV, and plain delimited TXT files with a header row. For Excel (XLSX), Parquet, or JSONL files, or for a live connection to a data warehouse, use Row Zero.

Excel worksheets are limited to 1,048,576 rows, and performance degrades well before that as formulas and formatting recalculate across the full grid. Google Sheets limits a spreadsheet to 10 million cells total across all sheets. A file bigger than that — or just large in file size — can slow down or crash both applications.

This tool is read-and-export only: search, sort, and export a filtered subset, but no in-place cell editing. For editing, formulas, and saved workbooks, open the file in Row Zero instead.

No. Opening, searching, sorting, and exporting a file on openbigcsv.com does not require an account. An account is only needed if you continue the same file in Row Zero.

Yes. openbigcsv.com is built and operated by Row Zero, Inc., the company behind the Row Zero spreadsheet. The free viewer here solves one narrow problem — opening a big file quickly — while Row Zero is the full connected-spreadsheet product, with plans starting at $0. See pricing.

If you arrive here already signed in to Row Zero, the site recognizes that and swaps the signup button for a direct link back into your account. If you're seeing a signup prompt anyway, you can still sign in normally at rowzero.com — no duplicate account is created.