# Callisto Calendar vs Do

The clearest difference is price: Callisto Calendar at Free against Do's $2.99. Callisto Calendar also leads on update cadence (every 2 weeks vs every 3 months). Do's advantage is in-app purchases (none vs 1). On ads, device support and iOS requirement there is nothing between them.

Callisto Calendar is free to download; Do costs $2.99 up front. Callisto Calendar sells 1 one-off in-app purchase. Do asks for nothing beyond the download.

Callisto Calendar ships an update every 2 weeks, Do every 3 months. The most recent releases landed on June 1, 2026 and September 16, 2026 respectively.

## The numbers

| Metric | Callisto Calendar | Do |
| --- | --- | --- |
| Price | **Free** | $2.99 |
| Rating | **[2.7 (3 ratings)](https://appshunter.io/ios/app/callisto-calendar/id1497394819/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 60.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 2 weeks** | Every 3 months |
| Monetization | Free with in-app purchases | — |
| Size | 11 MB | 2 MB |
| Requires iOS | **16.0** | 17.0 |
| Devices | iPhone | iPhone |
| Age rating | 4+ | +4 |
| Developer | [Duraid Abdul](https://appshunter.io/developer/1417002529) | [Code with Beto](https://appshunter.io/developer/1735070532) |

## What reviewers say

### Callisto Calendar

[App page](https://appshunter.io/ios/app/callisto-calendar/id1497394819)

This app helps you organize your schedule with intuitive event creation, powerful search, and multiple calendar views. It offers smart reminder suggestions and integrates astronomical data for planning.

**Highlights:** Natural language event creation, Powerful event search, Event notes and URL editing, Week and Month calendar views, Smart reminder suggestions, Sunset, sunrise, and moon phase data

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Callisto Pro | Free | one-time |


### Do

[App page](https://appshunter.io/ios/app/do-simple-task-manager/id6479227548)

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

**In-app purchases:** none


## Frequently asked questions

### Is Callisto Calendar free?

Callisto Calendar is free to download, with in-app purchases available.

### Is Do free?

Do costs $2.99, with no in-app purchases.

### Do Callisto Calendar or Do have ads?

Neither Callisto Calendar nor Do shows ads.

### Which is updated more often, Callisto Calendar or Do?

Callisto Calendar ships an update every 2 weeks, and Do every 3 months. Most recently, Callisto Calendar was updated on June 1, 2026 and Do on September 16, 2026.

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