# Stirz - Calc & Smart Alarm — Wake Up with Math Challenges

> Math-based smart alarm clock with customizable wake-up challenges. (iPhone/iPad app by Kosuke Yamanaka.)

- Source: https://appshunter.io/ios/app/stirz-calc-and-smart-alarm/id6449697827 (this page in markdown: same URL + `.md`)
- Developer: [Kosuke Yamanaka](https://appshunter.io/developer/1690125217)
- Category: Health & Fitness, Lifestyle
- Price: Free with in-app purchases
- Rating: 4.75/5 from 4 App Store ratings · 2 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.0 · 147 MB
- Languages: Japanese
- Released: 2023-07-19
- Data updated: 2026-06-01
- Monetization: freemium
- User reviews in markdown: https://appshunter.io/ios/app/stirz-calc-and-smart-alarm/id6449697827/reviews.md

## What is Stirz?

Wake up your mind with Stirz! Our unique alarm system ensures you start your day on a smart note. With our new Smart Alarm feature, wake up gently during your light sleep phase. When it's time to wake up, you'll need to solve a set number of calculation questions to silence the alarm. Start each day with an invigorating mental exercise and a gentle wake-up routine that gets your brain going!

Free plan, you can: 
 - Smart Alarm
 - Set the number of calculation questions needed to turn off the alarm, ranging from 1 to 5.
 - Challenge yourself with two-digit calculations.
 - Choose from five basic alarm sounds to find the wake-up call that works best for you.
 
With the Stirz Plus plan, you can: 
 - Enjoy an ad-free experience.
 - Test your skills with three-digit calculations.
 - Access exclusive premium alarm sounds for a unique wake-up call.
 - Choose your wake-up song from your own music library.

------
Information about Stirz Plus Subscription
 - The Stirz Plus subscription will be charged from App Store account upon purchase.
 - The Stirz Plus subscription will auto-renew 24 hours before the end of each subscription period. The renewal will be of the same type and at the same price as the original subscription.
 - To avoid automatic renewal, you must cancel the Stirz Plus subscription at least 24 hours before it expires.
 - You can manage or cancel your Stirz Plus auto-renewable subscription by accessing your user settings in the App Store after the purchase.
 - It is not possible to cancel the Stirz Plus subscription during the active subscription period.

Privacy Policy: https://cob-app.com/2023/07/02/privacy-policy-stirz/
Terms of Service: https://cob-app.com/2023/07/02/terms-of-service-stirz/

## Key features

- Smart Alarm for gentle wake-ups
- Math calculation challenges to disable alarm
- Customizable number of math problems (1-5)
- Two-digit and three-digit calculation options
- Basic and premium alarm sound selection
- Wake-up to personal music library (premium)

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Plus: Unlock all features | $3.99 | per month |
| Plus: Unlock all features | $19.99 | per 6 months |
| Plus: Unlock all features | $31.99 | per year |


## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/stirz-calc-and-smart-alarm/id6449697827/reviews.md

### 1/5 — Doesn't work

*2025-10-30*

Whenever i press "start" the alarm just instantly goes off and doesn't stay on for the night no matter what time I have it set to

### 2/5 — No la recomiendo

*2023-11-02*

La idea es buena y útil, pero tiene muchísimos fallos. Llegué tarde a un examen y no lo pude hacer por culpa de la alarma que no sonó y esto me ha pasado varias veces. Hay veces que de repente empieza a sonar, otras en las que cuando la pones empieza a sonar y tienes que hacer cálculos… Tiene muchos fallos no la recomiendo. Lo que hago yo es ponerme esta alarma y después me pongo la del móvil por si acaso esta no suena.

## Frequently asked questions about Stirz

### How does Stirz's Smart Alarm work?

The Smart Alarm feature aims to wake you up during your light sleep phase, which is generally a gentler and more refreshing experience than being woken abruptly from deep sleep.

### What kind of math problems does Stirz use?

The free version offers two-digit calculations, while the Stirz Plus subscription allows for more challenging three-digit calculations. You can set the number of problems required to turn off the alarm from 1 to 5.

### Can I use my own music as an alarm with Stirz?

Yes, the Stirz Plus subscription includes the ability to choose your wake-up song from your own music library, offering a personalized wake-up experience.

### How much does Stirz Plus cost?

Stirz Plus offers several subscription options: $3.99 per month, $19.99 for six months, and $31.99 for a year. These prices are charged via your App Store account.

### How do I cancel my Stirz Plus subscription?

You can manage or cancel your auto-renewable Stirz Plus subscription by accessing your user settings in the App Store after purchase. Cancellation must be done at least 24 hours before the subscription period ends.

### Is Stirz available on Android devices?

Based on the provided data, Stirz is currently supported on iPhone and iPod. Information regarding Android compatibility is not available.

### How often is Stirz updated?

The latest version of Stirz was released on October 16, 2023. The app was initially released on July 19, 2023, suggesting a relatively active update schedule.

### What is the age rating for Stirz?

Stirz has an age rating of 4+, making it suitable for a wide range of users. The app's content is considered appropriate for young children and older audiences.

## Version history (last 4 releases)

### 1.1.2 — 2023-10-16

- Bug fixes implemented

### 1.1.1 — 2023-09-01

- Bug fixes implemented

### 1.1.0 — 2023-08-08

New feature: Smart Alarm
 - Tracks your physical movements before wake-up, utilizing one of four preset intervals (10, 15, 20, or 30 minutes) to identify your light sleep phase for a gentler wake-up experience.
 - For optimal results, place the device on your bed, close to your pillow.
 - The Smart Alarm feature can be turned off at your convenience.

### 1.0.0 — 2023-07-19

No release notes.

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## More apps by Kosuke Yamanaka

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All apps by Kosuke Yamanaka: https://appshunter.io/developer/1690125217

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-01.*