Clockwork - Watch App

Clockwork - Watch App

Measure watch accuracy!

23 ratings
27 reviews
Free
In-App Purchases

Details

  • Released
  • Updated
  • April 1, 2022
  • June 22, 2026

Features

Clockwork - Watch App video #1 for iPhone
Clockwork - Watch App screenshot #2 for iPhone
Clockwork - Watch App screenshot #3 for iPhone
Clockwork - Watch App screenshot #4 for iPhone
Clockwork - Watch App screenshot #5 for iPhone
Clockwork - Watch App screenshot #6 for iPhone
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About

This app allows you to measure the accuracy of your watches using your phone's camera. It compares an image of your watch to an atomic clock to calculate its timekeeping offset. Track accuracy over time with graphs and store detailed watch information.

Measure accuracy using images
Atomic clock synchronization
Accuracy over time graphs
Store detailed watch information
Dark mode support
Digital and analog atomic clock
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What's New in Clockwork

1.3.8

June 22, 2026

Improved camera measurements. Clockwork now detects your watch on screen and automatically focuses on it, helping measurement photos look clear and sharp.

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In-App Purchases

$5.99

Clockwork Premium

This purchase opens premium features

User reviews

Please add a zoom when taking a picture

It’s really hard talking a picture without being able to zoom in. I need a 2x, 1x, and 0.5x zoom button for my iPhone Pro Max, which has 3 different cameras on the back. It’s too small to see otherwise, and getting closer only results in a blurry picture.

Pointless trial

It took a nice picture but that was it. The app didn’t take a note of the watch time so only recorded the atomic clock time with no delta.
I deleted the app.

App closing

Now on IOS 18.3 the app open and close immediately

Very inaccurate

Tried the free version to begin with and it looked like it was giving a reasonable and believable result (given the limited five measurements you get with the free version).

I paid for the full version and added three watches. These were all quartz analog watches and known to be very accurate (as checked with my radio-controlled watch).

However, I got some very odd results. Two of the watches returned -2.5 and -3.5 seconds per day while the third was apparently -74.3s/day! This is a very large amount for a quartz watch and would have been obvious to me previously as I compared them to my radio-controlled watch.

As a test I measured my radio-controlled watch (which never fails to pick up the time signal) and the app says it’s +7.7 seconds / day! This really is a terribly inaccurate and unreliable app.

I contacted the developer but never received a reply.

I just wanted to know if there was anything I was doing wrong as there aren’t and real instructions.

I got a refund as this app clearly needs some work.
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Great simple app

Seems to work well for relative tracking - just don’t understand why when setting the watch with the displayed atomic clock to the correct time the measurement using an image says its 2 seconds slow - so there is a difference of about 2 seconds between the two?

Developer apps

FAQ

How does this app measure watch accuracy?

The app uses your phone's camera to take a picture of your watch. It then synchronizes the image capture time with an atomic clock and compares it to the time displayed on your watch in the image to calculate any offset.

What are the benefits of measuring watch accuracy?

Measuring accuracy can indicate when your watch might need servicing. Consistent accuracy can also increase a watch's resale value, particularly for vintage timepieces.

Does the app require any special equipment?

No, unlike many other watch measurement apps, this app does not require any third-party equipment. It relies solely on your phone's camera and an atomic clock sync.

Can I track my watch's accuracy over time?

Yes, the app features beautifully crafted graphs that allow you to visualize your watch's accuracy measurements over time. These graphs can show trends and inform you about your watch's performance.

Is there a cost associated with using this app?

The app is free to download and use, but it offers in-app purchases. These purchases likely unlock additional features or customization options beyond the core functionality.