# RayDay vs BigDose

The clearest difference is in-app purchases: BigDose at none against RayDay's 3. BigDose also leads on update cadence (every 2 days vs every 3 weeks). RayDay's advantage is iOS requirement (17.0 vs 26.0). On price, ads and device support there is nothing between them.

Both are free to download. RayDay sells 3 in-app purchases, starting at $4.99 per 7 days. BigDose asks for nothing beyond the download.

RayDay ships an update every 3 weeks, BigDose every 2 days. The most recent releases landed on October 17, 2026 and October 16, 2026 respectively.

## The numbers

| Metric | RayDay | BigDose |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.0 (2 ratings)](https://appshunter.io/ios/app/rayday-vitamin-d-tracker/id6761286896/reviews)** | — |
| Number of ratings | **2** | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 2 days** |
| Monetization | Free | — |
| Size | 28 MB | 10 MB |
| Requires iOS | **17.0** | 26.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Jakub Laszczyk](https://appshunter.io/developer/568719342) | [Grant Perry](https://appshunter.io/developer/1689489185) |

## What reviewers say

### RayDay

[App page](https://appshunter.io/ios/app/rayday-vitamin-d-tracker/id6761286896)

This app calculates your daily window for natural Vitamin D production based on your location and skin type. It provides solar path visualization, forecasts, and atmospheric data to help you optimize sun exposure safely.

**Highlights:** D-Window Calculator, Live Solar Path visualization, 7-Day D-Window Forecast, Skin Type Personalization, Smart Sun Exposure Notifications, Real-time UV Index & Atmospheric Data, Home Screen Widget

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| RayDay Weekly | $4.99 | per 7 days |
| RayDay Yearly | $24.99 | per year |
| Early Supporter Yearly | $24.99 | per year |


### BigDose

[App page](https://appshunter.io/ios/app/bigdose/id6781472633)

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

**In-app purchases:** none


## Frequently asked questions

### Is RayDay free?

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

### Is BigDose free?

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

### Do RayDay or BigDose have ads?

Neither RayDay nor BigDose shows ads.

### Which is updated more often, RayDay or BigDose?

RayDay ships an update every 3 weeks, and BigDose every 2 days. Most recently, RayDay was updated on October 17, 2026 and BigDose on October 16, 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.*