Comparison

IntervalTimer Duo vs Circuit Timer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

IntervalTimer Duo

Features
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IntervalTimer Duo is a simple and easy-to-use interval timer app for iPhone and iPad that alternates between two customizable timers. 【Key Uses】 • HIIT (High-Intensity Interval Training) • Pomodoro Technique (work and break cycles) • Cooking timing management • Stretching and yoga routines • Study and rest cycle management 【Features】 • Automatically alternate between two timers • Each timer adjustable from 1 second to 60 minutes • Preset feature to save and instantly recall favorite settings (1 preset free; unlimited presets: Premium) • Share presets via link — let friends import your timer setup in one tap (Premium) • Set counter to track progress toward your target sets (Premium) • Audio notifications and vibration when timers end • Live Activity shows remaining time on Lock Screen and Dynamic Island (Premium) • Customizable alert sounds (extra sounds: Premium) • Simple and intuitive interface 【Preset Sharing】 • Share your favorite timer configurations via link • Recipients can import presets with a single tap • Sync routines with your team or workout partners 【Ease of Use】 • One-tap start, pause, and reset • Quick time setting with preset buttons • Visual circular progress bars show remaining time • Second timer can be enabled/disabled as needed • Set counter tracks completed sets toward your goal 【Free & Premium】 The app is free to download and use. After installing, all premium features are unlocked for a 14-day free trial. When the trial ends, premium features require a one-time purchase (pay once, use forever) — a Universal Purchase shared between iOS and macOS. Free forever: • Two timers running alternately (1 second to 60 minutes each) • One saved preset • Basic alert sounds • Audio and vibration notifications when timers end • Circular progress bar Premium (one-time purchase, or during the free trial): • Unlimited presets • Preset sharing via link • Set counter • Additional premium alert sounds • Live Activity on Lock Screen and Dynamic Island 【Compatibility】 • iPhone and iPad • Available in English, Japanese, French, German, and Spanish 【Universal Purchase】 If you own the macOS version, you can use the iOS version at no additional cost. A simple yet fully-featured interval timer app that's perfect for any timing needs. Privacy Policy: https://techback.info/interval-timer/ios/privacy-policy.html Terms of Use (EULA): https://techback.info/interval-timer/ios/terms-of-use.html

About

Circuit Timer

Features
Read full description

Build custom interval training circuits and run them with precision timing, voice announcements, and haptic feedback. CREATE YOUR PERFECT WORKOUT Design circuits with unlimited intervals, each with its own name, duration, and alarm sound. Set loop counts on individual intervals or the entire circuit. Choose from 24 alarm sounds, enable voice countdown, or both. STAY IN THE ZONE A full-screen player with a progress ring, countdown timer, and interval timeline keeps you focused. The last 3 seconds pulse to keep you ready for what's next. Voice announcements call out interval names so you never have to look at your screen. NEVER MISS A BEAT Live Activities put your timer on the Lock Screen and Dynamic Island. Background notifications keep you on track even when you switch apps. Start circuits hands-free with Siri. APPLE WATCH Run circuits from your wrist with real-time heart rate zones, active calories, and haptic alerts. Your watch keeps going even when the screen dims with Always-On Display support. TRACK YOUR PROGRESS View workout history with streaks, completion stats, and total training time. Save workouts to Apple Health as High Intensity Interval Training sessions. FREE TO START - 1 circuit with full features — alarms, haptics, voice, history CORE UPGRADE - Unlimited circuits - iCloud sync across devices - Apple Health integration PRO UPGRADE - Everything in Core - Apple Watch companion app Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

IntervalTimer Duo4 screens
Circuit Timer3 screens

Verdict

The call

IntervalTimer Duo and Circuit Timer are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. IntervalTimer Duo sells 1 one-off in-app purchase and Circuit Timer sells 2 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

IntervalTimer Duo ships an update every 2 weeks, Circuit Timer monthly. The most recent releases landed on September 7, 2026 and September 3, 2026 respectively.

ScorecardNo meaningful differences
IntervalTimer Duo versus Circuit Timer: the parameters behind the verdict, then further details
ParameterIntervalTimer DuoCircuit Timer
PriceFreeFree
Update frequencyEvery 2 weeks — betterMonthly
AdsNoNo
In-app purchasesYesYes
DevicesiPhone, iPad, MaciPhone, iPad, Apple Watch
Requires iOS26.126.0 — better
Further details — not scored
Size10 MB7 MB
Age rating4+4+
Developerkosuke konumaLawman Services, LLC

In-app purchases

1 purchases

IntervalTimer Duo

One-time1
  • Full Version$2.99
2 purchases

Circuit Timer

One-time2
  • Core$2.99
  • Pro$4.99

Questions

Is IntervalTimer Duo free?
IntervalTimer Duo is free to download, with in-app purchases available.
Is Circuit Timer free?
Circuit Timer is free to download, with in-app purchases available.
Do IntervalTimer Duo or Circuit Timer have ads?
Neither IntervalTimer Duo nor Circuit Timer shows ads.
Which is updated more often, IntervalTimer Duo or Circuit Timer?
IntervalTimer Duo ships an update every 2 weeks, and Circuit Timer monthly. Most recently, IntervalTimer Duo was updated on September 7, 2026 and Circuit Timer on September 3, 2026.

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