# Prism vs Sky Dose

The clearest difference is update cadence: Sky Dose at every 4 days against Prism's every 11 days. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Prism sells 1 in-app purchase, starting at $1.99 per month and Sky Dose sells 2 in-app purchases, starting at $3.99 per month. Whichever you choose, the download price is not the number that matters.

Prism ships an update every 11 days, Sky Dose every 4 days. The most recent releases landed on October 11, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | Prism | Sky Dose |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 11 days | **Every 4 days** |
| Size | 3 MB | 51 MB |
| Requires iOS | 26.0 | 26.0 |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, iPad |
| Age rating | 4+ | 12+ |
| Developer | [剑炜 陈](https://appshunter.io/developer/1868267178) | [besserly UG (haftungsbeschrankt)](https://appshunter.io/developer/1886013171) |

## What reviewers say

### Prism

[App page](https://appshunter.io/ios/app/prism-sunlight-tracker/id6758259341)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Prism Premium (Monthly) | $1.99 | per month |


### Sky Dose

[App page](https://appshunter.io/ios/app/sky-dose-vitamin-d-tracker/id6760735495)

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $3.99 | per month |
| Yearly | $29.99 | per year |


## Frequently asked questions

### Is Prism free?

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

### Is Sky Dose free?

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

### Do Prism or Sky Dose have ads?

Neither Prism nor Sky Dose shows ads.

### Which is updated more often, Prism or Sky Dose?

Prism ships an update every 11 days, and Sky Dose every 4 days. Most recently, Prism was updated on October 11, 2026 and Sky Dose on October 14, 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.*