Why video calls create carbon
With remote work and online classes now routine, video calls take up a large part of the day. Platforms such as Zoom, Teams and Google Meet are convenient, but an hour of HD video passes through data centers, CDNs and cell towers and uses a lot of energy. According to Purdue University and MIT research, an hour-long call with the camera on produces an estimated 54 g CO₂.
The most important variable is whether the camera is on. With it off, only audio and screen sharing are sent, which cuts carbon by about 96%. Someone with 10 hours of video calls a week who lowers their camera-on share from 70% to 30% saves about 1.1 kg CO₂ a year. The effect multiplies when a whole team does it.
Real figures vary with video resolution, number of participants, platform and local electricity mix. The calculator is a simple educational estimate and may differ from precise corporate reporting data.
Tips for using the calculator
Adjust the sliders to match your real habits and your current yearly CO₂ appears in real time. Use the "Reduce camera-on share" slider to simulate how much you save by cutting camera time.
Platform multipliers are reference values reflecting differences in encoding and data efficiency. Public data on per-platform energy use is scarce, so the margin of error is large. Focus on the relative difference between camera on and off rather than on absolute values.
Frequently asked questions
- Doesn't turning the camera off reduce engagement?
- The camera matters in presentations and discussions, but in listen-focused settings such as large webinars and lectures, switching it off has little effect on engagement. Turning it on selectively, depending on the situation, already makes a big difference.
- Which is greener, a voice call or a video call?
- A video call with the camera off uses about as much energy as a voice call. What matters is whether video data is sent. Screen sharing also creates a video stream, so sharing your screen only when needed helps too.
- Wouldn't holding fewer meetings be even more effective?
- Reducing the number of meetings is the most direct way to save. Replace anything that can be handled with shared documents, voice notes or Slack threads, and drop it. For more on switching to asynchronous collaboration, see the asynchronous collaboration guide below.
