# Otona Calendar vs Graffer電子署名アプリ

The clearest difference is rating: Otona Calendar at 4.1 against Graffer電子署名アプリ's 2.1. Otona Calendar also leads on update cadence (fortnightly vs every 5 weeks). Graffer電子署名アプリ'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. Otona Calendar sells 1 one-off in-app purchase. Graffer電子署名アプリ asks for nothing beyond the download.

Otona Calendar holds the better App Store score, 4.1 against 2.1. That said, the two scores are not equally well evidenced: Graffer電子署名アプリ has 173 ratings behind it against 10, so its average is the more settled of the two.

Otona Calendar ships an update fortnightly, Graffer電子署名アプリ every 5 weeks. The most recent releases landed on October 29, 2026 and August 21, 2026 respectively.

## The numbers

| Metric | Otona Calendar | Graffer電子署名アプリ |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.1 (10 ratings)](https://appshunter.io/ios/app/otona-calendar-simple-planner/id987143083/reviews)** | [2.1 (173 ratings)](https://appshunter.io/ios/app/graffer/id1484937227/reviews) |
| Number of ratings | 10 | **173** |
| Positive reviews | 41.7% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Fortnightly** | Every 5 weeks |
| Monetization | Free with in-app purchases | **Free** |
| Size | 49 MB | 14 MB |
| Requires iOS | 16.0 | **15.1** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Masaki Hirano](https://appshunter.io/developer/870094068) | [Graffer, Inc.](https://appshunter.io/developer/1484937226) |

## What reviewers say

### Otona Calendar

[App page](https://appshunter.io/ios/app/otona-calendar-simple-planner/id987143083)

A straightforward calendar app designed for immediate use without complex setup. It leverages your existing iOS calendar data, allowing seamless integration and immediate functionality. Features include event management, template creation, and availability searching.

**Highlights:** Template functionality, Event moving and copying, Availability search, Custom calendar creation, Immediate use without setup

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $3.99 | one-time |


### Graffer電子署名アプリ

[App page](https://appshunter.io/ios/app/graffer/id1484937227)

This app facilitates secure digital signatures using your My Number Card for online government services. It guides you through the process of verifying your identity and completing digital signatures without storing personal information on your device.

**Highlights:** Digital signature with My Number Card, Identity verification, Secure online government applications, No personal data stored in app, NFC/Felica compatible

**In-app purchases:** none


## Frequently asked questions

### Is Otona Calendar free?

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

### Is Graffer電子署名アプリ free?

Graffer電子署名アプリ is free to download, with no in-app purchases.

### Which has better reviews, Otona Calendar or Graffer電子署名アプリ?

Otona Calendar is rated higher. Otona Calendar averages 4.1 out of 5 from 10 ratings, while Graffer電子署名アプリ averages 2.1 from 173 ratings.

### Do Otona Calendar or Graffer電子署名アプリ have ads?

Otona Calendar shows ads; Graffer電子署名アプリ does not.

### Which is updated more often, Otona Calendar or Graffer電子署名アプリ?

Otona Calendar ships an update fortnightly, and Graffer電子署名アプリ every 5 weeks. Most recently, Otona Calendar was updated on October 29, 2026 and Graffer電子署名アプリ on August 21, 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.*