BTC51 Browser Extension
Your Complete Bitcoin Dashboard
Track Bitcoin price, 51% attack cost, Fear & Greed index, and more - right in your browser toolbar.
Features
Real-Time Price
Live BTC price from CoinGecko, Binance, or Coinbase with 7-day mini chart
51% Attack Cost
Real-time calculation based on current hashrate and hardware prices
Fear & Greed Index
Live market sentiment with extreme value alerts
Halving Countdown
Block-based countdown to the next Bitcoin halving
Portfolio Tracker
Track holdings, cost basis, and P/L - all stored locally
Price Alerts
Set unlimited price targets with browser notifications
Converter & Tools
Quick converter, DCA calculator, fee estimator, address validator
Multi-Language
English, Chinese, Spanish, Japanese, Arabic
Dark & Light Themes
Choose your preferred theme or follow system settings
New Tab Dashboard
Optionally replace your new tab page with a full Bitcoin dashboard featuring daily Satoshi quotes and Bitcoin obituary archive.
Privacy First
All data stored locally on your device. No accounts, no tracking, no analytics.
Data Sources
Price data from CoinGecko, Binance, Coinbase. Network data from mempool.space. Sentiment from Alternative.me.
Requirements
Chrome 88+ or any Chromium-based browser (Edge, Brave, Opera)
Keyboard Shortcut
Press Ctrl+Shift+B (Windows/Linux) or Cmd+Shift+B (Mac) to open quickly