# CalendarDuo vs Basic Calculator.

The clearest difference is in-app purchases: CalendarDuo at none against Basic Calculator.'s 1. Basic Calculator.'s advantage is update cadence (every 2 weeks vs every 4 months) and iOS requirement (13.0 vs 15.1). On price, ads and device support there is nothing between them.

Both are free to download. Basic Calculator. sells 1 one-off in-app purchase. CalendarDuo asks for nothing beyond the download.

CalendarDuo ships an update every 4 months, Basic Calculator. every 2 weeks. The most recent releases landed on October 15, 2026 and October 17, 2026 respectively.

## The numbers

| Metric | CalendarDuo | Basic Calculator. |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.7 (147 ratings)](https://appshunter.io/ios/app/basic-calculator/id6447476116/reviews)** |
| Number of ratings | — | **147** |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | Yes | Yes |
| Update frequency | Every 4 months | **Every 2 weeks** |
| Monetization | **Ad-supported** | Free with in-app purchases |
| Size | 41 MB | 69 MB |
| Requires iOS | 15.1 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Chun Lam](https://appshunter.io/developer/1565498900) | [Edison Largo](https://appshunter.io/developer/978541799) |

## What reviewers say

### CalendarDuo

[App page](https://appshunter.io/ios/app/calendarduo/id1589593639)

Easily manage and view holidays from two different countries simultaneously. This utility app offers instant switching between calendars, a dual-view display, and helpful tools like a world clock and currency exchange.

**Highlights:** Switch between two world calendars instantly, Duo-view with holidays from two countries, Daylight Saving Time dates, Currency exchange rate, World clock, Add notes

**Features:** macOS Compatibility

**In-app purchases:** none


### Basic Calculator.

[App page](https://appshunter.io/ios/app/basic-calculator/id6447476116)

A straightforward and user-friendly calculator app designed for quick calculations. It features a display log, a backspace key for corrections, and supports both decimal points and commas.

**Highlights:** Display log for calculations, Backspace key for corrections, Decimal point and comma support, Designed for quick calculations, User-friendly interface

**Features:** macOS Compatibility

**In-app purchases (1)**

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


## Frequently asked questions

### Is CalendarDuo free?

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

### Is Basic Calculator. free?

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

### Do CalendarDuo or Basic Calculator. have ads?

Both CalendarDuo and Basic Calculator. show ads.

### Which is updated more often, CalendarDuo or Basic Calculator.?

CalendarDuo ships an update every 4 months, and Basic Calculator. every 2 weeks. Most recently, CalendarDuo was updated on October 15, 2026 and Basic Calculator. on October 17, 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.*