How to Open 1GB CSV in Browser
Excel crashed trying to open a huge CSV? You don't need to install any software. GigaSieve can stream-open files of any size directly in your browser.
Why this is safe
GigaSieve uses the browser's File API to read your file directly from disk. The file never leaves your computer - no upload, no server processing.
The Problem
Microsoft Excel has a hard limit of about 1 million rows. Google Sheets is even worse at 10 million cells. When you try to open a CSV larger than these limits, the app either crashes, freezes, or silently truncates your data.
The Solution: Streaming
Instead of loading the entire file into memory, GigaSieve reads your file in small chunks (1MB at a time). This means you can preview, search, and analyze files of virtually any size - 1GB, 10GB, or more.
Step-by-Step
- Open GigaSieve
Go to /app
- Drop your CSV file
Drag the file into the drop zone, or click to browse
- Wait for scanning
Progress bar shows how much has been parsed. For 1GB, expect 10-30 seconds.
- Explore & Filter
Use the filter box to search. Results appear instantly in the virtual scroll viewer.
Performance Tips
- Close other browser tabs to free up RAM
- Use Chrome or Edge for best performance (Firefox works but is slower)
- If your CSV has many columns, filtering may be slower - try filtering by line content instead
FAQ
Will this work offline?
Yes, once the page is loaded, you can disconnect from the internet. Processing is 100% local.
Is my data sent anywhere?
No. The file is read directly from your disk using the browser's File API. There's no upload step.
Can I edit the CSV?
GigaSieve is read-only. It's designed for analysis and filtering, not editing.