Doom SaverFree tool
Screen Time Calculator
How much of your life your phone takes at your current daily screen time, in days a year and years of your life.
Published By Samina Jameel
Multiply your daily screen time by the years you have left, then divide by 24. At 4 hours a day, a 30 year old who lives to 73 will spend about 7.2 years of the rest of their life on their phone, or 10.8 years of their waking life.
Put in your own numbers below. Every half hour a day you cut gives you back about 7.6 days a year.
Full 24 hour days, over the 43 years to age 73.
Counting only waking hours, with 8 hours of sleep a night.
1,460 hours a year.
4 hours out of 16 awake.
Given back to you every year.
At 4 hours a day, age 30. Change the numbers above; nothing you type leaves this page.
How the calculator works
It uses three simple sums, so you can check any result by hand.
- Each year: hours a day × 365 ÷ 24 gives full days a year.
- Rest of your life: hours a day × years left ÷ 24 gives years, counting all 24 hours of a day.
- Waking life: hours a day × years left ÷ 16 gives years of the time you are awake, assuming 8 hours of sleep. The CDC recommends at least seven hours of sleep a night for adults (CDC).
It assumes your screen time stays the same every year, which it will not. Treat the result as a picture of your current habit, not a forecast.
Screen time over a lifetime, worked out
The same sums for common amounts of daily phone use, over 50 years:
| Phone a day | Each year | Of your waking day | Over 50 years | Waking years, over 50 |
|---|---|---|---|---|
| 1 hour | 15.2 days | 6% | 2.1 years | 3.1 years |
| 2 hours | 30.4 days | 13% | 4.2 years | 6.3 years |
| 3 hours | 45.6 days | 19% | 6.3 years | 9.4 years |
| 4 hours | 60.8 days | 25% | 8.3 years | 12.5 years |
| 5 hours | 76 days | 31% | 10.4 years | 15.6 years |
| 6 hours | 91.3 days | 38% | 12.5 years | 18.8 years |
| 7 hours | 106.5 days | 44% | 14.6 years | 21.9 years |
| 8 hours | 121.7 days | 50% | 16.7 years | 25 years |
For a sense of scale: the app analytics firm Sensor Tower estimates that in 2025 people spent about 3.6 hours a day in mobile apps worldwide (State of Mobile 2026). That is a modelled industry estimate rather than a measured census, but at that rate 50 years comes to about 7.5 years of full days.
How to find your real daily screen time
Guessing is not good enough. People are poor judges of their own phone use. A review of 47 studies comparing what people reported with what their devices logged found the two agree only moderately, and estimates were accurate in only about 5% of the studies (Parry et al., 2021). On Android, open Settings, then Digital Wellbeing, for your time today and the last seven days. This guide shows where it is on each phone and which numbers to read.
What to do with the number
A large number on its own changes little. What tends to work is changing the moment of use: putting a pause in front of the apps that eat your time, or a visible clock inside them. How to stop doomscrolling covers ten approaches with the research behind each.
Common questions
How many years of my life will I spend on my phone?
Multiply your daily screen time in hours by the years you have left, then divide by 24. At 4 hours a day with 43 years to go, that is about 7.2 years, or 10.8 years of waking life.
How do you calculate screen time per year?
Multiply hours a day by 365, then divide by 24 for full days. Four hours a day is 1,460 hours, or about 60.8 days, a year.
What is the average daily screen time?
Estimates vary by country and by how use is measured. Sensor Tower, an app analytics firm, estimates about 3.6 hours a day in mobile apps worldwide in 2025. Ofcom measured UK adults online for 4 hours 30 minutes a day in May 2025, 77% of it on smartphones. More figures, with sources.
How much screen time is too much?
There is no single safe number. Researchers look at what the time displaces, such as sleep, work and people, more than the hours themselves. A useful test is whether you would choose to spend that much time on purpose.
Does this calculator save what I type?
No. The sums run in your browser and nothing you enter is sent anywhere or stored.
Sources
- Sensor Tower (2026). State of Mobile 2026. sensortower.com/blog/state-of-mobile-2026
- Ofcom (2025). Online Nation 2025. www.ofcom.org.uk
- Centers for Disease Control and Prevention, National Center for Health Statistics (2026). Mortality in the United States, 2024, Data Brief No. 548. www.cdc.gov/nchs/products/databriefs/db548.htm
- United Nations, Department of Economic and Social Affairs (2024). World Population Prospects 2024. www.un.org/development/desa/pd/world-population-prospects-2024
- Centers for Disease Control and Prevention. About Sleep. www.cdc.gov/sleep/about/index.html
- Parry, D. A., Davidson, B. I., Sewall, C. J. R., Fisher, J. T., Mieczkowski, H. and Quintana, D. S. (2021). A systematic review and meta-analysis of discrepancies between logged and self-reported digital media use. Nature Human Behaviour, 5. doi.org/10.1038/s41562-021-01117-5
Doom Saver shows you the number while it is still growing
Grim, a hooded knight, sits on top of the apps you choose with a running timer for today, and falls apart as the minutes add up. Free on Google Play.
Get it on Google Play