# Doubling Time Calculator vs Countdown 321

The clearest difference is in-app purchases: Doubling Time Calculator at none against Countdown 321's 4. Doubling Time Calculator also leads on iOS requirement (13.0 vs 18.6). On price, ads and device support there is nothing between them.

Both are free to download. Countdown 321 sells 4 one-off in-app purchases. Doubling Time Calculator asks for nothing beyond the download.

## The numbers

| Metric | Doubling Time Calculator | Countdown 321 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (2 ratings)](https://appshunter.io/ios/app/countdown-321/id6499282435/reviews)** |
| Number of ratings | — | **2** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | — | Every 5 months |
| Monetization | — | Free |
| Size | 41 MB | 59 MB |
| Requires iOS | **13.0** | 18.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Stage Coding](https://appshunter.io/developer/1637068135) | [Later Creative LLC](https://appshunter.io/developer/1444959285) |

## What reviewers say

### Doubling Time Calculator

[App page](https://appshunter.io/ios/app/doubling-time-calculator/id1619683812)

**Features:** macOS Compatibility

**In-app purchases:** none


### Countdown 321

[App page](https://appshunter.io/ios/app/countdown-321/id6499282435)

Track time until future events or elapsed time since past milestones. Customize with personal photos and colors, and share your countdowns as images. Receive notifications for important dates and import birthdays automatically.

**Highlights:** Countdown and count-up tracking, Customizable widgets for home and lock screens, Personalized backgrounds and styles, Event notifications and milestone alerts, Birthday import from contacts, Shareable countdown images

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Bread-sized tip | $1.99 | one-time |
| Full Version | $2.99 | one-time |
| Peanut Butter-Sized Tip | $2.99 | one-time |
| Jam-Sized Tip | $3.99 | one-time |


## Frequently asked questions

### Is Doubling Time Calculator free?

Doubling Time Calculator is free to download, with no in-app purchases.

### Is Countdown 321 free?

Countdown 321 is free to download, with in-app purchases available.

### Do Doubling Time Calculator or Countdown 321 have ads?

Neither Doubling Time Calculator nor Countdown 321 shows ads.

---

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