1. Home
  2. 🔧 Utilities
  3. Kello
Kello

Kello

Mechanical Watch Analyzer

5 ratings
161 reviews
📚 Education
🔧 Utilities
$9.99

Details

  • Released
  • Updated
  • July 11, 2010
  • July 9, 2026

Features

Developer

Coldflower Design Corp.
✨Promote your app ✨
Kello screenshot #1 for iPhone
Kello screenshot #2 for iPhone
Kello screenshot #3 for iPhone
📌Ready
Reviews summary↘︎
⭐161
Reviews↘︎
🔄6+ apps
Alternatives↘︎
❓5 answered
FAQ↘︎
📦~ in 2 months
Updates frequency↘︎
🖼️Get Icon
Icons↘︎

About

This app analyzes the accuracy of mechanical watches by listening to their ticking sounds through your device's microphone. It compares the watch's rhythm to the precise system clock to reveal timekeeping differences. Supports a wide range of watch frequencies and offers guidance on identifying mechanical timepieces.

✓Microphone-based watch sound analysis
✓Comparison to iOS system clock
✓Automatic detection of 8 common watch frequencies
✓Guidance on identifying mechanical watches
✓Displays timekeeping differences
Show original description

What users say

Summarized from real user reviews of Kello. Based on 5 reviews and a 2.8/5 average, it highlights the 7 positives and 11 negatives reviewers mention most about this Utilities app.

Positive things

  • 💡Innovative watch timing solution at affordable price
  • ✅Accurate readings when properly configured
  • 🎯Correctly identifies beat frequency (BPH)
  • ⚙️Useful for watch regulation and adjustment
  • 📱Portable alternative to expensive timing machines
  • 🔧Helps regulate mechanical watches to within seconds
  • 🎧Works with standard iPhone earbuds microphone

Negative things

  • 🎙️Highly sensitive to microphone quality and placement
  • 🔇Requires extremely quiet environment to function
  • 📊Inconsistent readings even in same position
  • ⚠️Frequent signal detection failures
  • 🔄High variability in results between measurements
  • ❌Doesn't work with many watch types/movements
  • 😤Steep learning curve with trial-and-error setup
  • 🚫Fails on thick case watches and dive watches
  • 💥Crashes frequently on some iOS versions
  • 🔌Struggles with quiet escapements (Miyota, etc.)
  • 📉Results unreliable for professional use
See all reviews

What's New in Kello

2.5

July 9, 2026

Recompiled against new SDKs, as required by the store operator's terms for continued sale. Unfortunately, for clients running on older hardware, this means that some OS versions are no longer supported. We believe that keeping the hardware you already own in good, operative condition, rather than replacing it with new hardware, is best for the environment. Particularly when paired with useful, software-based tools to help service and repair other hardware and tools, like watches, which when well cared for can outlive their original owners. Previous versions of Kello will continue to run and function as they always have on older hardware. Keep ticking.

More

User reviews

Most RecentHighest RatedLowest Rated

Since ios17, I can no longer take measurements. When will you update Kello?

Since ios17, I can no longer take measurements. When will you update Kello?
Doug douDoug dou

Worked for me

I have an Oris Titan that I received as a gift around 2005. The watch has been slow (about 6-7 min a month slow) for years. I have sent it for servicing around 2007 (stripped crown) and then complete overhaul in late 2019. I mentioned it being slow each time but continued to be slow after service. I finally decided to open the back and see about adjusting it myself. The first adjustment wasn’t enough, so I adjusted it a second time this weekend Saturday morning, and for the first time ever it’s looking like it might be slightly fast. I have been just comparing it to my phone time daily, but thought it would be nice to check it with this app after reading about it. The watch back was already installed when I got this app later that night. At first it wouldn’t register, so I put the watch with half the case resting on the bottom of the phone with the watch back directly over the phone mic. I also had to put a clear glass mixing bowl over the phone and watch. Once I did that it read and analyzed the watch…+3.6 and then +4 on a second check. This seems to be what I am seeing after a day. Time will tell, but so far it looks like it works well. I have another watch running too fast. If I make any future adjustments to any watch I’ll check it with the app while adjusting.
Show more
ChemitsoChemitso

Semplice ma efficace

Provata con Omega, Longines, Zenith e Hamilton vintage. Consiglio di mettere il microfono delle cuffie tra la cassa e un cuscinetto da scatola di orologi.
AndrewGnzzAndrewGnzz

Ne fonctionne pas

Micro interne externe boîtier ouvert ou pas
Ne détecte pas la fréquence et au pire signal irrégulier
Quand on clique sur la demande d’info l’app crash

1 an que la société ne s’intéresse pas à son app

J’ai demandé un remboursement
RaidentattooRaidentattoo

Funciona Perfeito

Funciona , testado com meu Breitling superocean. Bateu em cima. 3.1 segundos / dia. Recomendo
Thomas FluesThomas Flues
See 156 more reviews

Developer apps

Twixt Time
Twixt Time

Accuracy tracker for watches

🔧 Utilities

(14)

$9.99 $19.99
See developer apps

User experience

🐞

Reported Bugs

10 issues

App crashes on iPhone 5 and iOS 6

Bug

Signal detection fails inconsistently

Bug

Frequency auto-detection varies wildly on same watch

Bug

Unstable signal readings despite strong initial signal

Bug

App hangs on 'determine frequency' step

Bug

Poor microphone compatibility with external mics

Bug

Results vary significantly between consecutive measurements

Bug

Crashes frequently during measurement process

Bug

Incompatibility with newer iOS versions

Bug

Microphone not detected on some devices

Bug
✨

Requested Features

10 requests

History log and data storage for watches

Feature

Graphical representation of timing data over time

Feature

Average readings over longer time periods

Feature

Watch profile saving functionality

Feature

Beat error measurement capability

Feature

Export feature for timing results

Feature

Fine-tuning control for amplification slider

Feature

Improved signal detection algorithm

Feature

Better microphone sensitivity recommendations

Feature

Compatibility with more iOS versions

Feature

FAQ

What does Kello do?

Kello analyzes the precision of mechanical watches by listening to their 'tick-tock' sounds via your device's microphone. It then compares the regularity of these sounds to the highly accurate iOS system clock to measure and display any timekeeping differences.

What watch frequencies does Kello support?

Kello automatically detects and supports eight of the most common frequencies used in mechanical watches, including 14,400, 16,200, 18,000, 19,800, 21,600, 25,200, 28,800, and 36,000 beats per hour (bph). This range accommodates the vast majority of mechanical timepieces made in the last century.

How can I tell if my watch is mechanical and compatible with Kello?

You can identify a mechanical watch by checking for terms like 'automatic' or 'shock-proof' on the dial, observing if the second hand sweeps smoothly or moves multiple times per second, listening for a ratcheting sound when turning the crown, or hearing a constant ticking noise when placed near your ear. Watches labeled 'quartz' are not mechanical.

Is Kello free to use?

Yes, Kello is available for free. There are no in-app purchases or advertisements mentioned in the application's description, indicating a completely free user experience.

What hardware is recommended for using Kello?

While Kello works with your device's built-in microphone, it performs best with an external microphone that has excellent frequency response between 10,000 and 20,000 Hz. This can help capture the watch's acoustic energy more accurately for analysis.