The arithmetic, for you

What a difference a day makes.

See how your Mondays add up and how much time could you take back over a year.

Enter your daily phone time to see what a year of phone-free Mondays could add up to. Try it for yourself, your household, or other group setting.

If you don’t know your average screen time, go to Settings on your phone, locate the Screen Time or Digital Wellbeing section, and tap the main chart or weekly graph to view your daily averages and app breakdown.

We’ve started off with 4.5 hours of use per day, as our team of researchers has concluded this is consistent with typical usage for young adults in Great Britain.

Source: IPA TouchPoints, 2025

A year of Mondays comes to

936

hours off the screen

whole days back

56.2

kg of CO₂e

Which is about as much CO₂ as is taken in by

2.6
mature trees in a year

All numbers are estimates

What if one in ten of us joined in? Those Mondays would add up to 1.2 billion hours away from our phones each year. That comes to about 72,000 tonnes a year, or what about 3.3 million mature trees take in over a year.

The method

These numbers are for illustrative purposes. Here’s how we worked them out.

Your time

We multiply the number of people by the number of phone hours not being used each Monday, then by the number of Mondays.

One person × 4.5 hours × 52 Mondays = 234 hours a year.

That’s almost ten full days’ worth of hours. What you do with them is up to you.

The carbon estimate

We use an illustrative digital-footprint estimate of 60 g CO₂e per hour, rounded from Mike Berners-Lee’s figure of 69 kg a year for an average smartphone user (about 3¼ hours a day, which works out to about 58 g an hour). Multiply that by your total hours for the carbon result.^⁠[1]

69 kg ÷ (3¼ h × 365) ≈ 58 g → 60 g an hour on the phone
234 hours × 60 g ≈ 14 kg CO₂e

A 1960s trade advertisement reading ‘Holy cow!’ above a photograph of a cow: the reaction to a year of screen time added up

If one in ten UK smartphone owners aged 16+ took part, we could reduce screen time by 1.2 billion hours each year. At an illustrative ~60 g CO₂e per active hour, that adds up to a footprint of about 72,000 tonnes of CO₂e. This is an estimate of the footprint associated with the avoided screen time, not a guaranteed emissions saving. Actual savings would be lower if replaced activities also use electricity or digital infrastructure.

For scale, that’s comparable to the annual CO₂ uptake of roughly 3.3 million mature trees, using a commonly cited average of 22 kg of CO₂ per mature tree per year, or about 45 trees for every tonne.^⁠[2] Actual uptake varies substantially by species, age, location and growing conditions.

1 mature tree, for a year = 22 kg
1,000 kg ÷ 22 kg ≈ 45 mature trees for a tonne
72,000 t ÷ 22 kg ≈ 3.3 million mature trees, for a year

It is a comparison in tree-years, not a claim that planting that many saplings would cancel anything out: a young tree takes in far less than a mature one.

The sources

Figure	Source	Scope
71 g CO₂e/hour	Istrate et al., Nature Communications 15:3724 (2024): 229 kg ÷ 3,230 hours a year	Global average; all digital content on all devices, networks and data centres
55 g CO₂e/hour	Carbon Trust white paper (2021, using 2020 data): video-on-demand streaming	Europe; electricity in use only, excludes manufacture; mostly TV viewing (UK: 48 g)
36 g CO₂/hour	IEA commentary, George Kamiya (2020): streaming video	Global 2019 average; electricity in use only
63 / 69 / 86 kg a year	Mike Berners-Lee, How Bad Are Bananas? (2020); set out by Everphone	Whole phone, including manufacture, at 1 h / ~3¼ h / 10 h a day; about 173 / 58 / 24 g an hour
~16 kg CO₂e a year	Cordella, Alfieri & Sanfelix, Journal of Industrial Ecology (2021)	One smartphone’s life cycle, replaced every two years, excluding networks
53 million	Finder (2025): 95% of UK adults aged 16+ own a smartphone	UK smartphone owners aged 16+: who “one in ten” is one in ten of

A few caveats

60 g an hour is the footprint of the activity, not emissions saved. Making and delivering a phone (about 15 kg a year, per Cordella et al., assuming a new phone every two years) is a fixed cost that doesn’t disappear when you put the phone down. Counting only what each extra hour adds, Berners-Lee’s figures give about 7 g an hour, or roughly 8,400 tonnes for the same 1.2 billion hours. This number tells you what those hours “weigh”, not what stopping them “saves”.
It’s whole-system (device, network and data centres), not phone-only. A phone’s own life cycle is about 16 kg a year (Cordella et al.). That’s roughly 10 g an hour at 4.5 hours a day, of which charging is about 1 g.
It’s indicative, not precise. Published figures run from a few grams to a few hundred grams an hour, depending on electricity mix, device and allocation method. Streaming is about 2–3 g an hour on France’s or Sweden’s grid. An early estimate of 3.2 kg an hour was later cut about eightfold by its own authors.

One household’s share of this is small: about 14 kg a person a year. Saying so is the point rather than an admission. The claim was always a collective one: it is what happens if one in ten UK smartphone owners keeps the same day, and at that size it is what about 3.3 million mature trees take in over a year. A campaign that made one household sound like that would be doing the thing this page was built to avoid.

And it is the smaller half of the story. Most of a phone’s emissions are spent making it, not using it, so the bigger lever by far is keeping the one you have for another year.

Why it matters

Every Monday · #MobileFreeMondays

Now go and get those hours.

Make the pledge as a personal commitment to try Mobile Free Mondays. No donation, petition, or proof required.

Count me in

A campaign by The Dead Good Club

Mobile Free Mondays · A Dead Good Club campaign

Every Monday · #MobileFreeMondays