Carbon Footprint of Firefox
IdleForest models one hour of Firefox use at about 22g of CO2.
Firefox browsing emissions come from active device energy, page complexity, media playback, extensions, and the web infrastructure behind each session.
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How this Firefox estimate is built
The estimate treats Firefox as a general-purpose browser where tab count, video-heavy pages, extensions, and session length are the main practical drivers.
- The 22gCO2e/hour estimate is in the same range as other active desktop browsing models.
- The yearly estimate uses 22gCO2e/hour x 3 hours/day x 365 / 1000 = 24.1kgCO2e/year.
- Tree offset math rounds 24.1kgCO2e/year divided by 20kgCO2e per tree-year up to 2 trees.
Calculation proof
How the estimate is calculated
Annual footprint formula
22g CO2e/hour x 3h/day x 365 / 1000 = 24.1kg CO2e/year
Tree offset formula
ceil(24.1kg CO2e / 20 kg CO2e per tree-year) = 2 rounded up
Source basis: This estimate combines the app's modeled hourly footprint, usage assumption, methodology notes, and linked research sources. It is directional and should be read as a transparent consumer estimate, not a vendor emissions disclosure.
What drives this estimate most
- Open tabs, video-heavy pages, and extensions can keep CPU and memory usage elevated.
- Long browsing sessions compound modest hourly energy demand into a meaningful yearly total.
- Device efficiency matters because the browser is only one part of the system load.
Assumptions and boundaries
- The estimate assumes active browsing rather than a single page load snapshot.
- It treats browser energy as a blend of app overhead, site complexity, and device behavior.
- It is designed as a habit-level estimate rather than a measurement of one exact tab setup.
Uncertainty note: Browser emissions are especially sensitive to browsing habits, tab count, extensions, and the complexity of the pages being rendered.
Yearly Impact Comparison
*IdleForest offsets ~200kg CO2/year on average per user.
Ways to reduce this footprint
- Close unused tabs and disable heavy extensions you no longer need.
- Prefer lighter browsing sessions on battery-efficient devices when possible.
- Reduce simultaneous media playback and script-heavy multitasking.
Estimate review
Who reviewed this estimate
Reviewed by: IdleForest Research Team
Role: Editorial Review
Organization: IdleForest
Last reviewed: May 10, 2026
These estimates are meant to help compare digital habits. They are directional, not exact reproductions of proprietary vendor accounting.
Sources
Nature Communications: The environmental sustainability of digital content consumption
Peer-reviewed life-cycle assessment covering web use, social media, video, music streaming, and video conferencing.
IEA: Data centres and data transmission networks
Provides broader context on the infrastructure behind cloud and network energy use.
MIT CEEPR: How much can we reduce CO2 by planting trees?
Supports the offset conversion used by IdleForest: roughly 20kg CO2 absorbed per mature tree per year, with wide real-world variation.
More questions about Firefox's carbon footprint
Does Firefox itself determine the carbon footprint?
Only partly. Website complexity, video playback, extensions, device efficiency, and electricity mix are usually the larger drivers.
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About IdleForest
IdleForest is a passive browser extension that plants trees while you browse, game, or stream. It uses your unused internet bandwidth to fund reforestation projects.
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