# Fluid Simulation vs Sleep

The clearest difference is rating: Fluid Simulation at 4.9 against Sleep's 4.3. Fluid Simulation also leads on monetization model (free with in-app purchases vs subscription) and review sentiment (96% vs 60%). Sleep's advantage is ads (none vs shown) and iOS requirement (13.0 vs 15.0). On price, in-app purchases and device support there is nothing between them.

Both are free to download. Fluid Simulation sells 15 in-app purchases, starting at $1.00 per 7 days and Sleep sells 12 in-app purchases, starting at $2.99 per 7 days. Whichever you choose, the download price is not the number that matters.

Fluid Simulation holds the better App Store score, 4.9 against 4.3. That said, the two scores are not equally well evidenced: Fluid Simulation has 90K ratings behind it against 9.8K, so its average is the more settled of the two. Written reviews point the same way: 96% of Fluid Simulation's written reviews are positive against 60% of Sleep's.

Fluid Simulation ships an update every 2 days, Sleep every 3 weeks. Both last shipped on October 28, 2026.

## The numbers

| Metric | Fluid Simulation | Sleep |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.9 (90K ratings)](https://appshunter.io/ios/app/fluid-simulation-antistress/id1443124993/reviews)** | [4.3 (9.8K ratings)](https://appshunter.io/ios/app/sleep/id1447478883/reviews) |
| Number of ratings | **90K** | 9.8K |
| Positive reviews | **96.2% of reviews** | 59.9% of reviews |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 2 days** | Every 3 weeks |
| Monetization | **Free with in-app purchases** | Subscription |
| Size | 70 MB | 61 MB |
| Requires iOS | 15.0 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Pavel Dobryakov](https://appshunter.io/developer/1443124992) | [Mosaic S.r.l.](https://appshunter.io/developer/570748343) |

## What reviewers say

### Fluid Simulation

[App page](https://appshunter.io/ios/app/fluid-simulation-antistress/id1443124993)

Engage with mesmerizing fluid dynamics simulations on your device. This app offers a visually stunning and calming experience, perfect for stress relief and relaxation. Explore swirling liquids and gases with simple touch controls.

**Highlights:** Interactive fluid dynamics, Stress relief and calming experience, Gorgeous visuals, Simple touch controls, Liquid, gas, and water simulation, Psychedelic and trippy visuals

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (15)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Fluid Premium | $1.00 | per 7 days |
| Fluid Premium | $3.00 | per month |
| Premium | $4.99 | per year |
| Fluid Premium | $6.00 | per month |
| Fluid Premium | $10.00 | per year |
| Premium | $0.49 | one-time |
| Particles | $0.99 | one-time |
| Particles | $1.99 | one-time |
| Fluid Premium | $3.00 | one-time |
| Fluid Simulation | $3.69 | one-time |
| Fluid Premium | $20.00 | one-time |
| Fluid Simulation | $23.00 | one-time |
| Discount | $29.99 | one-time |
| Fluid Premium | $30.00 | one-time |
| Fluid Simulation | $33.00 | one-time |

**What reviewers like**

- 🌈 Beautiful and mesmerizing visuals
- 🧘‍♀️ Calming and relaxing experience
- 👍 Intuitive and easy to use
- 🎨 Customizable settings and presets
- ⭐️ High-quality graphics and animations

**What reviewers complain about**

- 💰 Premium features locked behind paywall
- 🔒 Limited customization options in free version
- 🐛 Occasional crashes or performance issues
- 📱 Smaller screen size can make controls tricky

**Reported bugs**

- Subscription issues and inability to access premium features
- Crashes or freezes when changing certain settings

**Requested features**

- Ability to save and share custom presets
- Option to change background color
- Slower animation speed for more control
- Integration with music or audio playback
- Support for larger screens and TVs


### Sleep

[App page](https://appshunter.io/ios/app/sleep/id1447478883)

Drift off to sleep with a variety of soothing content, including narrated stories, guided meditations, and ambient sounds. Manage stress and anxiety to improve sleep quality and establish a consistent bedtime routine.

**Highlights:** Bedtime stories, Sleep meditations, Extensive sound library, Fade out timer, Bedtime reminder

**Features:** Vision Pro support

**In-app purchases (12)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly Pro | $2.99 | per 7 days |
| Weekly Pro with Free Trial | $2.99 | per 7 days |
| Weekly Premium with Free Trial | $3.99 | per 7 days |
| Weekly Bundle - Free Trial | $3.99 | per 7 days |
| Weekly Bundle - No Free Trial | $3.99 | per 7 days |
| Help fall asleep | $4.99 | per 7 days |
| Weekly Premium with Free Trial | $4.99 | per 7 days |
| Weekly Bundle | $4.99 | per 7 days |
| Weekly Bundle with Free Trial | $4.99 | per 7 days |
| Bundle - Weekly - Free Trial | $6.99 | per 7 days |
| Bundle - Weekly | $6.99 | per 7 days |
| Monthly Pro with Free Trial | $9.99 | per month |

**What reviewers like**

- 🌙 Relaxing and calming sounds
- 🌟 Customizable sound mixing
- 🕰️ Sleep timer feature
- 🌊 Variety of nature/ambient sounds
- 📚 Soothing bedtime stories

**What reviewers complain about**

- 💰 Excessive premium subscription cost
- 🔒 Limited free features
- 🙄 Aggressive upselling for premium
- 🔇 Subpar quality of some free sounds
- 🤖 Robotic/unnatural narration in stories

**Reported bugs**

- Sound playback stops when screen is locked
- Frequent app crashes on older devices

**Requested features**

- More free sound options
- Ability to save custom sound mixes
- Integration with smart home devices
- Offline mode for sound playback
- Personalized sleep tracking and analysis


## Frequently asked questions

### Is Fluid Simulation free?

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

### Is Sleep free?

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

### Which has better reviews, Fluid Simulation or Sleep?

Fluid Simulation is rated higher. Fluid Simulation averages 4.9 out of 5 from 90K ratings, while Sleep averages 4.3 from 9.8K ratings.

### Do Fluid Simulation or Sleep have ads?

Fluid Simulation shows ads; Sleep does not.

### Which is updated more often, Fluid Simulation or Sleep?

Fluid Simulation ships an update every 2 days, and Sleep every 3 weeks. Most recently, Fluid Simulation was updated on October 28, 2026 and Sleep on October 28, 2026.

---

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