# 海のカレンダー vs Billma

The clearest difference is in-app purchases: 海のカレンダー at none against Billma's 1. Billma's advantage is update cadence (every 6 weeks vs every 4 months) and iOS requirement (12.0 vs 15.0). On price, ads and device support there is nothing between them.

Both are free to download. Billma sells 1 in-app purchase, starting at $4.99 per month. 海のカレンダー asks for nothing beyond the download.

海のカレンダー ships an update every 4 months, Billma every 6 weeks. The most recent releases landed on October 12, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | 海のカレンダー | Billma |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | Yes | Yes |
| Update frequency | Every 4 months | **Every 6 weeks** |
| Size | 27 MB | 41 MB |
| Requires iOS | 15.0 | **12.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Akira Yamamoto](https://appshunter.io/developer/1401669011) | [ACTN K.K.](https://appshunter.io/developer/1519939443) |

## What reviewers say

### 海のカレンダー

[App page](https://appshunter.io/ios/app/id1502904539)

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

**In-app purchases:** none


### Billma

[App page](https://appshunter.io/ios/app/billma/id1519939441)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| BillmaPlus | $4.99 | per month |


## Frequently asked questions

### Is 海のカレンダー free?

海のカレンダー is free to download, with no in-app purchases.

### Is Billma free?

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

### Do 海のカレンダー or Billma have ads?

Both 海のカレンダー and Billma show ads.

### Which is updated more often, 海のカレンダー or Billma?

海のカレンダー ships an update every 4 months, and Billma every 6 weeks. Most recently, 海のカレンダー was updated on October 12, 2026 and Billma on October 6, 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.*