# Calibrator Pro vs Interval Voice Clock

The clearest difference is price: Calibrator Pro at Free against Interval Voice Clock's $1.99. Calibrator Pro also leads on iOS requirement (13.0 vs 15.0). Interval Voice Clock's advantage is in-app purchases (none vs 2) and update cadence (every 2 weeks vs every 2 months). On rating, ratings volume and ads there is nothing between them.

Calibrator Pro is free to download; Interval Voice Clock costs $1.99 up front. Calibrator Pro sells 2 one-off in-app purchases. Interval Voice Clock asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 5.0 for Calibrator Pro against 5.0 for Interval Voice Clock. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

Calibrator Pro ships an update every 2 months, Interval Voice Clock every 2 weeks. The most recent releases landed on June 11, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | Calibrator Pro | Interval Voice Clock |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/calibrator-pro/id1642756685/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/interval-voice-clock/id6476801545/reviews) |
| Number of ratings | 1 | 1 |
| Positive reviews | — | 66.7% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 2 weeks** |
| Monetization | **Free with in-app purchases** | Paid |
| Size | 18 MB | 32 MB |
| Requires iOS | **13.0** | 15.0 |
| Devices | iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [XRPro, LLC](https://appshunter.io/developer/1642756687) | [Ryo Okamoto](https://appshunter.io/developer/418850607) |

## What reviewers say

### Calibrator Pro

[App page](https://appshunter.io/ios/app/calibrator-pro/id1642756685)

This utility app allows trained users to calibrate the intrinsic parameters of their Structure Sensor accessory. It requires a specific calibration target and is designed for advanced users to optimize sensor performance. Calibration is quick, taking only a few minutes once trained.

**Highlights:** Calibrate Structure Sensor intrinsic parameters, Requires specific calibration target, Designed for trained users, Quick calibration process (3-5 minutes), In-app payment for calibrations, Bulk purchase discounts available

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| One sensor calibration | $49.99 | one-time |
| Two hundred calibrations | $999.99 | one-time |


### Interval Voice Clock

[App page](https://appshunter.io/ios/app/interval-voice-clock/id6476801545)

This app announces the current time at customizable intervals, allowing for hands-free time checks. It offers adjustable volume, voice options, and background playback, functioning entirely offline.

**Highlights:** Customizable announcement intervals, Adjustable announcement volume, Choice of male or female voice, Background playback support, Offline functionality, Multiple announcement types

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

**In-app purchases:** none


## Frequently asked questions

### Is Calibrator Pro free?

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

### Is Interval Voice Clock free?

Interval Voice Clock costs $1.99, with no in-app purchases.

### Which has better reviews, Calibrator Pro or Interval Voice Clock?

Calibrator Pro and Interval Voice Clock are both rated 5.0 out of 5 on the App Store, from 1 and 1 ratings respectively.

### Do Calibrator Pro or Interval Voice Clock have ads?

Neither Calibrator Pro nor Interval Voice Clock shows ads.

### Which is updated more often, Calibrator Pro or Interval Voice Clock?

Calibrator Pro ships an update every 2 months, and Interval Voice Clock every 2 weeks. Most recently, Calibrator Pro was updated on June 11, 2026 and Interval Voice Clock on September 22, 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.*