# Interpupillary Distance Meter vs Penlight.

The clearest difference is update cadence: Penlight. at daily against Interpupillary Distance Meter's every 6 weeks. Penlight. also leads on rating (5.0 vs 4.6). Interpupillary Distance Meter's advantage is ratings volume (512 vs 1) and device support (3 vs 1). On ads and in-app purchases there is nothing between them.

Interpupillary Distance Meter costs $0.99 and Penlight. $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Penlight. holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: Interpupillary Distance Meter has 512 ratings behind it against 1, so its average is the more settled of the two.

Interpupillary Distance Meter ships an update every 6 weeks, Penlight. daily. The most recent releases landed on October 20, 2026 and October 18, 2026 respectively.

## The numbers

| Metric | Interpupillary Distance Meter | Penlight. |
| --- | --- | --- |
| Price | **$0.99** | $1.99 |
| Rating | [4.6 (512 ratings)](https://appshunter.io/ios/app/interpupillary-distance-meter/id1481753106/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/penlight/id6621271103/reviews)** |
| Number of ratings | **512** | 1 |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 6 weeks | **Daily** |
| Monetization | **Free** | Paid |
| Size | 8 MB | 1 MB |
| Requires iOS | **12.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 12+ | 4+ |
| Developer | [Ubicolor Ltd](https://appshunter.io/developer/828691698) | [My Call Bag LLC](https://appshunter.io/developer/1243282862) |

## What reviewers say

### Interpupillary Distance Meter

[App page](https://appshunter.io/ios/app/interpupillary-distance-meter/id1481753106)

Quickly measure your inter pupillary distance using your iPhone or iPad. Achieve highly accurate results to 0.1mm for both near and far pupil distances. The app features large text for readability and supports dark mode.

**Highlights:** Accurate IPD measurement to 0.1mm, Near and far pupil distance, Glasses-free measurement for accuracy, Large, readable text, Dark mode support

**In-app purchases:** none

**What reviewers like**

- 👍 Simple and easy to use
- 🚀 Accurate measurements for some users
- 💡 Pure IPD measurement
- 👍 Works quickly
- 👍 Remarkable use of iPhone tech

**What reviewers complain about**

- 🐛 Inaccurate measurements reported
- 🐛 Compatibility issues with iPads
- 🐛 Does not work on older iPhones
- 🐛 Inability to read results without glasses
- 🐛 App crashes or fails to recognize eyes

**Reported bugs**

- Inaccurate IPD readings (up to 10% off)
- Does not work on iPad
- Incompatible with devices without true depth camera
- Cannot read results with glasses off
- App fails to recognize eyes

**Requested features**

- Allow measurement of near PD
- Improve compatibility information on App Store
- Fix compatibility for iPads and older iPhones
- Allow reading results with glasses on


### Penlight.

[App page](https://appshunter.io/ios/app/penlight/id6621271103)

This app provides a digital penlight with adjustable brightness and a built-in ruler for quick measurements. It also features color inversion for different examination needs and easy calibration using a credit card.

**Highlights:** Adjustable digital penlight brightness, Credit card calibration for accuracy, Color inversion for light/dark modes, Metric and imperial ruler, Educational examination tool

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

**In-app purchases:** none


## Frequently asked questions

### Is Interpupillary Distance Meter free?

Interpupillary Distance Meter costs $0.99, with no in-app purchases.

### Is Penlight. free?

Penlight. costs $1.99, with no in-app purchases.

### Which has better reviews, Interpupillary Distance Meter or Penlight.?

Penlight. is rated higher. Interpupillary Distance Meter averages 4.6 out of 5 from 512 ratings, while Penlight. averages 5.0 from 1 ratings.

### Do Interpupillary Distance Meter or Penlight. have ads?

Neither Interpupillary Distance Meter nor Penlight. shows ads.

### Which is updated more often, Interpupillary Distance Meter or Penlight.?

Interpupillary Distance Meter ships an update every 6 weeks, and Penlight. daily. Most recently, Interpupillary Distance Meter was updated on October 20, 2026 and Penlight. on October 18, 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.*