Comparison

Zero CO2 vs Climate Timer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Zero CO2

This app tracks your phone's carbon footprint from data usage and helps you offset emissions by planting trees. Monitor your CO2 output and see how your reforestation efforts compensate for it, receiving certificates for each planted tree.

Highlights
  • Monitors phone carbon footprint
  • Tracks CO2 emissions from data usage
  • Compensates emissions by planting trees
  • Visualizes CO2 emissions and tree compensation
  • Provides certificates for planted trees
Features
Read full description

ZeroCO2 monitors your phone's carbon footprint and keeps track of the CO2 emissions from your device. These CO2 emissions come from the data usage of your device. All cloud-services, emails, search queries, social network activities etc, are facilitated by large Data Centers, which consume large amounts of electricity to keep your data streams flowing. Over its lifetime, an iPhone can emit up to 60 kilograms of CO2. This electricity typically does not come 100% from green sources, and therefore leads to CO2 emissions. That's equivalent to more than 300 kilometers driving in a petrol-fueled car. Do you want your phone to become CO2-neutral? Then use the app to plant trees to compensate your emissions! With its comprehensive graphs, you can easily monitor how much CO2 you emit, and how your planted trees compensate these emissions. With every planted tree, you receive a certificate that proves the authenticity and shows the location of the planted tree. Prevent climate change, and become a carbon-neutral iPhone user! Note: Trees are planted by our partner Tree-Nation, the worldwide platform to reforest the world and fight climate change. All trees planted by Tree-Nation are certified by the best in class and most renowned certification standards that exist in this field. For this, Tree-Nation works with third-party certification organizations such as VCS, Gold Standard, and Plan Vivo.

About

Climate Timer

Track critical climate change deadlines and lifelines, discover positive news, and manage personal actions. Customize your experience with background themes and home screen widgets.

Highlights
  • Climate change deadline countdown
  • Renewable energy and land protection data
  • Climate news updates
  • Personal climate action planner
  • Customizable background themes
  • Home screen widget support
Features
Read full description

This application displays information published on "ClimateClock.world" and manages climate change self-action. 1. DEADLINE Time left to limit global warming to 1.5℃. 2. LIFELINE • World's energy from renewables • Land protected by indigenous people • Loss & Damage owed by G20 nations • Loss & Damage owed by G7 nations • Green Climate Fund 3. News Good news about climate change. 4. My actions Set My Actions against climate change for housing, transportation, food, consumer goods, and leisure. 5. Background selection • Theme color • Specified color • Image (Switching display of global warming-related images at 1-minute intervals from the free material site "Pixabay.com") 6. Widget Can place DEADLINE widget on home screen The display content accesses "ClimateClock.world" every 24 hours and downloads the latest. The displayed contents are subject to change. The content is displayed according to the device language, but as of November 2022, it is only available in English and Portuguese. (Default language is English, news is always in English only)

Screenshots

Zero CO24 screens
Climate Timer4 screens

Verdict

The call

The clearest difference is review sentiment: Zero CO2 at 100% against Climate Timer's 50%. Zero CO2 also leads on rating (5.0 vs 3.0) and update cadence (every 3 days vs every 11 months). Climate Timer's advantage is in-app purchases (none vs 1) and ads (none vs shown). On price, device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Zero CO2 sells 1 one-off in-app purchase. Climate Timer asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Zero CO2 holds the better App Store score, 5.0 against 3.0. Both are backed by a comparable volume of ratings — 4 and 1 respectively. Written reviews point the same way: 100% of Zero CO2's written reviews are positive against 50% of Climate Timer's.

UpkeepUpdate frequency

Zero CO2 ships an update every 3 days, Climate Timer every 11 months. The most recent releases landed on September 11, 2026 and September 20, 2026 respectively.

Scorecard7 real differences · 3 level
Zero CO2 versus Climate Timer: the parameters behind the verdict, then further details
ParameterZero CO2Climate Timer
PriceFreeFree
Rating5.0 (4 ratings) — better3.0 (1 ratings)
Positive reviews100.0% of reviews — better50.0% of reviews
Number of ratings4 — better1
Update frequencyEvery 3 days — betterEvery 11 months
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPodiPhone, iPad
Requires iOS15.5 — better16.1
Further details — not scored
Size40 MB30 MB
Age rating12+4+
DeveloperCaramba App DevelopmentMAKOTO SASAKI

Customer experience

Zero CO2

All ratings4 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Climate Timer

All ratings1 ratings
Positive0.0%
Neutral100.0%
Negative0.0%
Written reviews2 reviews
Positive50.0%
Neutral50.0%
Negative0.0%

In-app purchases

1 purchases

Zero CO2

One-time1
  • Plant your tree$0.99
None

Climate Timer

No in-app purchases

Questions

Is Zero CO2 free?
Zero CO2 is free to download, with in-app purchases available.
Is Climate Timer free?
Climate Timer is free to download, with no in-app purchases.
Which has better reviews, Zero CO2 or Climate Timer?
Zero CO2 is rated higher. Zero CO2 averages 5.0 out of 5 from 4 ratings, while Climate Timer averages 3.0 from 1 ratings.
Do Zero CO2 or Climate Timer have ads?
Zero CO2 shows ads; Climate Timer does not.
Which is updated more often, Zero CO2 or Climate Timer?
Zero CO2 ships an update every 3 days, and Climate Timer every 11 months. Most recently, Zero CO2 was updated on September 11, 2026 and Climate Timer on September 20, 2026.

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