# SafeAuth vs Light Ruler

The clearest difference is update cadence: Light Ruler at weekly against SafeAuth's every 4 months. SafeAuth's advantage is iOS requirement (15.6 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. SafeAuth sells 4 in-app purchases, starting at $0.99 per 7 days and Light Ruler sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

SafeAuth ships an update every 4 months, Light Ruler weekly. The most recent releases landed on October 7, 2026 and September 29, 2026 respectively.

## The numbers

| Metric | SafeAuth | Light Ruler |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Weekly** |
| Monetization | — | Free with in-app purchases |
| Size | 12 MB | 1 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Suna Ordulu](https://appshunter.io/developer/1754727111) | [小倩 徐](https://appshunter.io/developer/6771586178) |

## What reviewers say

### SafeAuth

[App page](https://appshunter.io/ios/app/safeauth-2fa-authenticator/id6761731896)

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly | $0.99 | per 7 days |
| Monthly | $2.99 | per month |
| Annual | $19.99 | per year |
| Lifetime | $39.99 | one-time |


### Light Ruler

[App page](https://appshunter.io/ios/app/light-ruler-photo-toolkit/id6779471175)

This photography calculator helps plan shots for landscape, long exposure, and night sky photography. It calculates shutter speed with ND filters, depth of field, and night sky exposure limits. All data is stored locally on your device.

**Highlights:** ND filter long exposure calculation, Equivalent exposure adjustments, Depth of field and hyperfocal distance, Night sky shutter speed limits, Angle of view and focal length comparison, Local data storage

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lifetime Pro Unlock | $3.99 | one-time |


## Frequently asked questions

### Is SafeAuth free?

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

### Is Light Ruler free?

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

### Do SafeAuth or Light Ruler have ads?

Neither SafeAuth nor Light Ruler shows ads.

### Which is updated more often, SafeAuth or Light Ruler?

SafeAuth ships an update every 4 months, and Light Ruler weekly. Most recently, SafeAuth was updated on October 7, 2026 and Light Ruler on September 29, 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.*