# Kello — user reviews > 161 indexed App Store user reviews of Kello by Coldflower Design Corp., rated 2.80/5 from 5 ratings. - Source: https://appshunter.io/ios/app/kello/id380539253/reviews - App overview in markdown: https://appshunter.io/ios/app/kello/id380539253.md - Rating breakdown: 5★ 1 · 4★ 1 · 3★ 1 · 2★ 0 · 1★ 2 ## What do users think of Kello? Overall sentiment: mixed **Pros** - 💡 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 **Cons** - 🎙️ 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 **Commonly reported bugs** - App crashes on iPhone 5 and iOS 6 - Signal detection fails inconsistently - Frequency auto-detection varies wildly on same watch - Unstable signal readings despite strong initial signal - App hangs on 'determine frequency' step - Poor microphone compatibility with external mics - Results vary significantly between consecutive measurements - Crashes frequently during measurement process - Incompatibility with newer iOS versions - Microphone not detected on some devices **Most requested features** - History log and data storage for watches - Graphical representation of timing data over time - Average readings over longer time periods - Watch profile saving functionality - Beat error measurement capability - Export feature for timing results - Fine-tuning control for amplification slider - Improved signal detection algorithm - Better microphone sensitivity recommendations - Compatibility with more iOS versions ## Newest reviews (15 of 161) ### 3/5 — Cheaper than a Timegrapher *2019-11-27, version 2.48* I have successfully used this app to adjust the rate of several Seiko and Orient automatic watches. The tricks are as follows: - place the watch crown down on top of the iPhone microphone on your iPhone earphones/microphone. I usually place a rubber band around the watch once the back is off to insure the microphone is tight against the crown. The microphone must touch the glass crown to conduct sound. - be in a very quiet area - record the rate over a long period of time such as 15 to 20 minutes because the rate will vary over time. - it's hard to adjust to 0 so I settle for anything slightly positive such as 0 to +6 seconds fast per day. At this slightly fast crown down rate the watch when worn on my wrist gains a few seconds per day. When the watch is more than 5 seconds ahead of real time I leave it stem up on my dresser for the night. Leaving it stem up, slows down the movement so it loses about 5 seconds over night. By choosing how many nights I leave the watch stem up versus crown up I can keep the watch within a few seconds of real time. Note a Timegrapher is a much better tool but runs $150.00 and up. ### 4/5 — Appli bien pratique. *2019-09-23* Efficace si utilisée telle qu’indiqué. Je recommande. ### 3/5 — Very nice *2018-04-11, version 2.48* Thanks very accurate app !! it would be nice to record the track of every watch in a data base that include brand, picture, specs day year. ### 2/5 — Unable to to use *2017-03-28, version 2.46* I had spent too much time try to regulate a Seiko 7s26 c movement so I thought I'd try this app. I spent $14 CDN and 2 hours. The best result I could achieve using iPhone 6s headphone/mic was UNSTABLE. I had to manually set the both to 21600. I tried with case back on/off. I could achieve 5 dot fidelity and a saw tooth wave only with back off and mic resting in the movement. Now that the case back has been off for 2 hours and the mic and my fingers have touched the movement I doubt the watch will run for a long time and it is still not regulated. Looks like I'm out $14 bucks for the app and probably $50 for the watch. ### 1/5 — Waste of money *2017-03-16, version 2.44* Especially after the last update totally useless app. Intensions were good but it doesn't work. If it was free I would shut up and just delete it but for the money I paid I expected something much better. And yes I tried lots of options even building an amp, piezo mic, professional mic, iPhone mic, guitar amp, preamp, equaliser. The result-I can hear tick tock but the app doesn't. It inly works with old loud movement watches and thin case. Even when I open the watch the the results are wrong. After spending lots of time and money trying make it work, I bought Timegrapher. If I started from that, I would save lots of time and cash and aggravation. Don't make my mistake and get yourself a timegtapher or take the watch to a local watch shop. ### 1/5 — Arnaque ! *2017-01-10* Des mesures aléatoires, même dans le plus grand silence. J'ai plusieurs fois testé une 16710 et les résultats sont compris entre -12s et +5s alors que la montre est dans la même position. En regardant l'application prendre la mesure on s'en rend tout de suite compte du mauvais fonctionnement. ### 3/5 — Not reliable *2016-08-28, version 2.43* Does not work consistently ### 1/5 — Complete Garbage *2016-07-29, version 2.43* Simply the worst app I've ever purchased. Save your money! ### 4/5 — Tres correct *2016-07-01* Correct et fonctionne plutot bien des l'instant ou la montre est ouverte. Vous poser le micro sur le mecanisme et les mesures sont vraie. Pour bricoler soit même sur des montres qui ne sont pas de luxe c'est suffisant. ### 1/5 — Stopped working *2016-06-01, version 2.43* May 2016. No longer picks up mike poor signal. Worked before ### 2/5 — Needs additional equipment or improvement *2016-03-29* This app is hit and miss. One of the holy grails for any amateur watch collector is a fast, reliable, easy way to measure accuracy in a mechanical watch. Kello tries, but ultimately fails with too many of my watches to merit an exceptional rating. Depending on the movement and acoustics of the case Kello typically has trouble trying to acquire a reliable signal, which if you're a dive watch collector happens annoyingly often. It's also been my experience that watches with a noisier escapement such as the ETA 2824 have a much easier time being measured than the quieter escapement of Miyota movements. I've followed the best practices in the how to guide and came up with the same result consistently. ### 1/5 — Lello *2016-02-21, version 2.43* Soldi buttati ### 1/5 — Very inaccurate compared to other apps *2016-02-12, version 2.43* I comped results with Hairspring, Watch Tuner (which returns beat error and amplitude) and a hardware time grapher. The results were consistently off (in comparison to other measurements by the aforementioned which were very similar). For equal money look at Watch Tuner. I measured an Omega 286, 30T2 and 2 ETA 2924-2s (with different grade finishes) to determine accuracy of results. ### 4/5 — Does it work *2016-01-25, version 2.43* Difficult at first, ambient sound has too be very quiet. Tested on Bulova 18,000 bph. Very good App, limited by poor microphone only. ### 4/5 — Buona *2015-12-02, version 2.43* Funziona sempre basta l'accortezza di metterci un bicchiere capovolto sopra l'orologio e il mic. che sia a contatto con il fondello. Comunque il prezzo è esagerato ## Most critical reviews (10 lowest-rated) ### 1/5 — Ne fonctionne pas *2022-03-06* 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 ### 1/5 — Non va *2021-09-23, version 2.49* Non va, no mi dice nemmeno i secondi di scarto ### 1/5 — Don’t waste your money. *2019-10-24* Unable to get a signal on any watch I tried. Don’t waste your money. There are better apps available. ### 1/5 — Rubbish *2019-08-25, version 2.48* Tested on Tudor oyster iPhone 5s iOS 12.4 with mic on JBL headphones. Took readings with watch in exactly the same position at 5 minute intervals. App showed full signal strength for each measurement yet result varied widely. Steady reading of 7 seconds per day fast, then 45 seconds, then 61 seconds. Would try to get refund but I’m sure it’s not worth the headache. No contact or feedback details provided within the app. Avoid! ### 1/5 — Catastrophe *2019-03-26* Fuyez, même en démontant le boîtier arrière il ne détecte pas bien. Cher, je leur ai juste fais un don là... ### 1/5 — Arnaque *2018-05-28* Cette application ne marche pas, j’ai essaye plusieurs fois sans succès. ### 1/5 — Mah *2018-04-11, version 2.48* Non sono mai riuscito a farla funzionare (testata su due Omega) ### 1/5 — Dumb app *2017-08-07, version 2.47* Does not have signal waste of ten bucks. I want my money back! ### 1/5 — I want my $14 back! *2017-05-11, version 2.47* Bose microphone resting on case back of very loud pocket watch. I get a perfect wave graph but then it suddenly says that the signal is unstable. It also keeps changing it's mind on the frequency. One time it's 16200, then next time it's 14000 on the same time piece! I've tried it with 3 watches and with both the Bose and internal mic and get the same results in a perfectly quiet room. I'm going to contact Apple Store to request a refund. ### 1/5 — Pointless *2017-04-29, version 2.47* When I first downloaded this app a while back, it worked ok. Now it just simply cannot hear the watch any longer. Don't bother. ## Most praised reviews (10 highest-rated) ### 5/5 — Since ios17, I can no longer take measurements. When will you update Kello? *2024-09-20* Since ios17, I can no longer take measurements. When will you update Kello? ### 5/5 — Worked for me *2024-02-26* 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. ### 5/5 — Semplice ma efficace *2023-04-06, version 2.49* 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. ### 5/5 — Funciona Perfeito *2021-10-17* Funciona , testado com meu Breitling superocean. Bateu em cima. 3.1 segundos / dia. Recomendo ### 5/5 — Works well *2018-03-21, version 2.48* I used this with an old speedmaster and it reliably detected the rate and gave a good prediction of the rate over several positions. I used an iPhone X with the supplied headset and microphone, being careful to place the microphone close to the escapement. ### 5/5 — A professional tool not a toy. *2015-05-11, version 2.43* Working great exactly the same result of my Vibrograf. Great job thanks ### 5/5 — Works well *2015-04-12, version 2.43* Worth the money. Took a little while to get the hang of it but got it working nicely in the end. Just need to find a quiet room. Watch now running more accurately than ever. ### 5/5 — Ottima app *2015-03-09, version 2.43* Vale i soldi che costa ### 5/5 — Fantastic app for those needing to regulate a watch. *2015-03-04, version 2.43* I tell you what this app has saved me a ton of time in regulating my watch collection. I have tired a few other ear buds with this app and for sure use the apple ear buds with this app and it will work flawless. I have all my watches running within +\- 2 seconds a day no joke this app is worth every penny and hope to see new functions in the future. ### 5/5 — Just what I was looking for - worked perfectly on Baume and Mercier Chrono with ETA 7750 movement *2014-12-14, version 2.43* Just what I was looking for - worked perfectly on a Baume and Mercier Chrono with ETA 7750 movement. Pressed mic (small silver disc) side of Apple earbud mic case against back of watch while on a felt pad. Results corrolated perfectly with my previous timing results using an atomic clock signal over a 24 hour period. --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-30.*