How we calculate your website’s climate footprint

We calculate your website’s expected climate footprint based on the servers that power it, the data traffic between user and server, and the energy consumed by your visitors’ devices during a visit. These calculations form the basis of your membership and the support that goes toward certified climate projects worldwide.

How much electricity does a web server use?

We assume that a web server runs 24 hours a day, all year round. A typical power consumption for a smaller server is around 200 watts, although many hosting solutions run multiple websites on the same server, which reduces the total consumption per website.
To ensure a simple and fair calculation, we apply a fixed value of 200 watts per server.

How much electricity does a website visitor use?

Here, we take a standard laptop with a 17” screen as our reference point. It uses roughly 73 watts while in use.
We also include additional electricity consumption from the household router, which we estimate at 200 watts per household.
However, the most important factor in calculating visitor electricity usage is the number of page views.

How many page views do we base our calculations on?

We base our calculations on the number of monthly page views provided by the company.
If this is not possible, we use publicly available estimates or gross numbers from traffic tools as the basis.

How much electricity does one page view use?

Our variable for time spent per page view comes from Nielsen Online, which publishes monthly statistics in this field. Their average for time spent per page view is around 50 seconds, so we use 60 seconds as our parameter, providing a 20% buffer.
We include all hours of the day, as visitors may access your website at any time, whether it is a business site or otherwise. Some companies have higher traffic than expected, others lower.

How much electricity do the cables between servers and data centres use?

Electricity consumption in the data cables that connect servers and users is set to 1 watt per month per page view.
We use a standard month of 31 days, which gives a built-in buffer of around 2%, since most months are 28–30 days.
For high-traffic websites, we can provide more specific calculations.