# Prism vs Vitamin D Window Widget

The clearest difference is in-app purchases: Vitamin D Window Widget at none against Prism's 1. Vitamin D Window Widget also leads on iOS requirement (18.0 vs 26.0). Prism's advantage is device support (3 vs 1). On price, update cadence and ads there is nothing between them.

Both are free to download. Prism sells 1 in-app purchase, starting at $1.99 per month. Vitamin D Window Widget asks for nothing beyond the download.

Prism ships an update every 11 days, Vitamin D Window Widget every 2 weeks. The most recent releases landed on October 11, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | Prism | Vitamin D Window Widget |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (2 ratings)](https://appshunter.io/ios/app/vitamin-d-window-widget/id6759223422/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 11 days** | Every 2 weeks |
| Monetization | — | Free |
| Size | 3 MB | 2 MB |
| Requires iOS | 26.0 | **18.0** |
| Devices | **iPhone, iPad, Apple Watch** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [剑炜 陈](https://appshunter.io/developer/1868267178) | [Airhopping, SL](https://appshunter.io/developer/1339572434) |

## 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 |


### Vitamin D Window Widget

[App page](https://appshunter.io/ios/app/vitamin-d-window-widget/id6759223422)

This app displays the optimal times of day for natural vitamin D production based on your location and the sun's elevation. It offers real-time sun schedules, smart widgets for home screen access, and notifications to help you maximize your sun exposure.

**Highlights:** Real-time sun schedule, Smart widgets, Daily schedule updates, Dynamic Island countdown, Location-based calculations, Offline functionality, Solar-themed design

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

**In-app purchases:** none


## Frequently asked questions

### Is Prism free?

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

### Is Vitamin D Window Widget free?

Vitamin D Window Widget is free to download, with no in-app purchases.

### Do Prism or Vitamin D Window Widget have ads?

Neither Prism nor Vitamin D Window Widget shows ads.

### Which is updated more often, Prism or Vitamin D Window Widget?

Prism ships an update every 11 days, and Vitamin D Window Widget every 2 weeks. Most recently, Prism was updated on October 11, 2026 and Vitamin D Window Widget on October 10, 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.*