Measure the Energy
of Any Website
See real-time power consumption, get efficiency ratings, and make the web sustainable. Free and open source.
Chrome
Firefox
Safari
Edge
Brave
Why Use Joule Energy Meter?
Real-Time Monitoring
See power consumption as you browse. Watch energy spike during heavy JavaScript or video playback.
Energy Grades
Every page gets an A+ to F grade. Compare sites and discover which are energy efficient.
Issue Detection
Identify energy-wasting elements: bloated JavaScript, unoptimized images, autoplay videos.
Carbon Footprint
See the environmental impact of your browsing. Small changes add up to big savings.
Privacy First
All analysis happens locally. No data leaves your browser. No tracking, no accounts.
Open Source
Fully open source. Audit the code, contribute improvements, or fork for your needs.
How It Works
Install the Extension
One click install from your browser's store. Works on Chrome, Firefox, Safari, Edge, and Brave.
Browse Normally
The extension runs in the background, analyzing every page you visit without slowing you down.
See the Impact
Click the icon to see real-time energy data. Badge shows the grade at a glance.
Sample Site Ratings
Energy grades for popular websites (lower is better)
Make the Web Sustainable
Every page view uses energy. Let's measure it, optimize it, and reduce it together.
Install Joule Energy Meter