# Zero CO2 vs Climate Timer

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.

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

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.

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.

## The numbers

| Metric | Zero CO2 | Climate Timer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (4 ratings)](https://appshunter.io/ios/app/zero-co2-get-climate-neutral/id1534365588/reviews)** | [3.0 (1 ratings)](https://appshunter.io/ios/app/climate-timer/id6444170266/reviews) |
| Number of ratings | **4** | 1 |
| Positive reviews | **100.0% of reviews** | 50.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Every 3 days** | Every 11 months |
| Monetization | Free with in-app purchases | **Free** |
| Size | 40 MB | 30 MB |
| Requires iOS | **15.5** | 16.1 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 12+ | 4+ |
| Developer | [Caramba App Development](https://appshunter.io/developer/349530108) | [MAKOTO SASAKI](https://appshunter.io/developer/908850577) |

## What reviewers say

### Zero CO2

[App page](https://appshunter.io/ios/app/zero-co2-get-climate-neutral/id1534365588)

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:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Plant your tree | $0.99 | one-time |


### Climate Timer

[App page](https://appshunter.io/ios/app/climate-timer/id6444170266)

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:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked 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.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*