# Call Deck vs Altos

The clearest difference is rating: Call Deck at 5.0 against Altos's 1.0. Call Deck also leads on iOS requirement (10.0 vs 14.4). Altos's advantage is update cadence (every 3 weeks vs every 3 months). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Call Deck holds the better App Store score, 5.0 against 1.0. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

Call Deck ships an update every 3 months, Altos every 3 weeks. Both last shipped on November 3, 2026.

## The numbers

| Metric | Call Deck | Altos |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/call-deck/id1277078038/reviews)** | [1.0 (1 ratings)](https://appshunter.io/ios/app/altos-air-analyzer-co2-check/id1562104053/reviews) |
| Number of ratings | 1 | 1 |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 weeks** |
| Monetization | Free | Free |
| Size | 19 MB | 43 MB |
| Requires iOS | **10.0** | 14.4 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Flatzap, LLC](https://appshunter.io/developer/1099057484) | [Woodenshark LLC](https://appshunter.io/developer/1236101386) |

## What reviewers say

### Call Deck

[App page](https://appshunter.io/ios/app/call-deck/id1277078038)

Organize contacts into shareable groups called "Decks." Choose to make your Decks public or private, inviting specific users to private groups. Easily share and access contact lists on your mobile device.

**Highlights:** Create contact groups (Decks), Public and private sharing options, Invite users to private Decks, Search and add public Decks, Access shared contacts on mobile

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Altos

[App page](https://appshunter.io/ios/app/altos-air-analyzer-co2-check/id1562104053)

Monitor your indoor air quality to optimize your environment for better focus and well-being. This app connects to a CO2 meter to provide real-time data and alerts, helping you maintain optimal air for productivity and rest.

**Highlights:** Real-time CO2 level updates, Brain Fuel graph visualization, Fresh air push notifications, Real-time home screen widget, CO2 concentration statistics

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Call Deck free?

Call Deck is free to download, with no in-app purchases.

### Is Altos free?

Altos is free to download, with no in-app purchases.

### Which has better reviews, Call Deck or Altos?

Call Deck is rated higher. Call Deck averages 5.0 out of 5 from 1 ratings, while Altos averages 1.0 from 1 ratings.

### Do Call Deck or Altos have ads?

Neither Call Deck nor Altos shows ads.

### Which is updated more often, Call Deck or Altos?

Call Deck ships an update every 3 months, and Altos every 3 weeks. Most recently, Call Deck was updated on November 3, 2026 and Altos on November 3, 2026.

---

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