Core vs Interval Flow
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Core
This app helps you stay focused during workouts by managing intervals, work times, and rest periods with clear visual and audio cues. Save custom routines for HIIT, Tabata, or boxing, and track your training history to monitor progress.
- Customizable interval timers
- Audio cues for work/rest phases
- Save and reuse workout routines
- Visual countdown and color coding
- Workout history and trend tracking
- Optional Pro features via in-app purchase
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Keep your focus on the workout Core takes care of the intervals, so you can stay with your training. Set your work time, rest time and sets, then follow a clear countdown and audio cues from the first round to the last. Made for your routine Build a timer for HIIT, Tabata, circuit training or boxing rounds. Save your usual workouts and have them ready when it is time to train again. Know when to move and when to recover A large countdown and distinct work and rest colors make each phase easy to recognize at a glance. Choose audio cues that suit the way you train. See the work you have put in Revisit completed sessions and see your weekly training trends. Your training history gives every session a place beyond the final countdown. Go further with Core Pro Unlock unlimited timers and duplicates, full workout history, monthly and yearly trends, and CSV export. These features require an in-app purchase. Core Pro is optional. Available plans and prices are shown before purchase. If you choose an auto-renewable subscription, payment is charged to your Apple Account at confirmation. It renews automatically unless canceled at least 24 hours before the current period ends. Manage or cancel your subscription in your App Store account settings. Privacy policy: https://yating-900.github.io/core-timer-site/privacy.html Terms of use: https://yating-900.github.io/core-timer-site/terms.html If you have any ideas to improve the App, please contact us via coretimerapp@gmail.com. Your feedback is highly valued!
Interval Flow
This app revolutionizes fitness routines with deep customization and advanced tracking for various activities like HIIT, Yoga, and CrossFit. It allows users to create, share, and follow personalized workouts with features like color-coded intervals, real-time progress tracking, and voice assistance.
- Color-coded intervals
- Customizable circuits
- Real-time progress tracking
- Voice assist and search
- Exercise library
- Workout sharing
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Interval Flow: Experience a Workout Revolution Interval Flow is your ultimate fitness companion, designed to transform your workout experience with deep customization and advanced tracking. This versatile app is perfect for a wide range of activities including HIIT, TABATA, CrossFit, Yoga, Pilates, Meditation, and more. With Interval Flow, you can stay focused on your fitness goals while the app handles the details. Key Features: - Color-Coded Intervals: Customize your workout visually with color-coded intervals. Set distinct colors for warm-ups, high-intensity bursts, rest periods, and more, to easily navigate through your routine. - Exercise Library: Build your workouts with ease! Add new exercises or select from the existing ones to tailor your workout to your specific needs. - Real-Time Progress Tracking: Keep a live tab on your workout progress. The dynamic interval list updates in real-time, ensuring you know exactly where you are in your routine. - Customizable Circuits: Create the perfect workout sequence by arranging various exercises into repeatable circuits tailored to your fitness level and goals. - Personalized Interval Warnings: Get timely alerts before an interval ends. Customize the warning sounds to suit your style, ensuring smooth transitions without missing a beat. - Interactive Workflow: Enjoy crafting your workouts with a user-friendly interface that’s as intuitive as it is functional. Setting up your ideal workout regime is now as engaging as the workout itself. - Voice Assist: Let our advanced voice assist guide you through your exercises, announcing what’s next so you can remain focused on your form and intensity. - Voice Search: Quickly find your favorite workouts using voice commands, making your preparation seamless and hands-free. - AirShare: Share your custom workouts with friends or clients effortlessly using AirDrop, enhancing connectivity and interaction. Why Choose Interval Flow? With Interval Flow, you don't just exercise, you experience a revolution in workout efficiency and enjoyment. The app’s intuitive interface and comprehensive customization options make it the optimal companion for anyone serious about fitness. Whether you're powering through a high-intensity session or seeking tranquility in yoga, Interval Flow adapts to your pace and preference. Unlock your potential with Interval Flow – where your workout meets innovation. Interval Flow Subscription: The app includes a 1 month long auto-renewable subscription with a 3-day free trial, which will unlock premium features, like unlimited workouts, timer program editing and autoplay and costs $4.99/ month. It will be charged to your credit card through your iTunes account and will automatically renew unless you canceled at least 24 hours before the end of the current period. Any unused portion of a free trial period will be forfeited when you purchase the subscription. Though your subscription for the current month cannot be canceled, you can turn auto-renewal off in your account settings after purchase. See the instructions here: https://support.apple.com/en-us/HT202039 You can read the terms of use and privacy policy here: https://kapi90.github.io/hiit_timer_privacy_policy.html End User License Agreement (EULA) of the App Store applies: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is review sentiment: Core at 100% against Interval Flow's 48%. Core also leads on monetization model (freemium vs subscription) and rating (5.0 vs 4.7). Interval Flow's advantage is update cadence (fortnightly vs every 33 months) and ratings volume (167 vs 4). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Core sells 3 in-app purchases, starting at $1.99 per month and Interval Flow sells 10 in-app purchases, starting at $4.99 per 3 months. Whichever you choose, the download price is not the number that matters.
Core holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Interval Flow has 167 ratings behind it against 4, so its average is the more settled of the two. Written reviews point the same way: 100% of Core's written reviews are positive against 48% of Interval Flow's.
Core ships an update every 33 months, Interval Flow fortnightly. The most recent releases landed on October 30, 2026 and October 23, 2026 respectively.
| Parameter | Core | Interval Flow |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (4 ratings) — better | 4.7 (167 ratings) |
| Positive reviews | 100.0% of reviews — better | 48.1% of reviews |
| Number of ratings | 4 | 167 — better |
| Update frequency | Every 33 months | Fortnightly — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Freemium — better | Subscription |
| Devices | iPhone, iPod | iPhone, iPad |
| Requires iOS | 15.0 — better | 18.6 |
| Further details — not scored | ||
| Size | 9 MB | 20 MB |
| Age rating | 4+ | 4+ |
| Developer | Yating Lu | Bence Kaposzta |
Customer experience
Core
Interval Flow
Bugs and requests
Core
Not enough reviews yet to summarise bugs or requests.
Interval Flow
Reported bugs
10 issues- Programs deleted after update
- App crashes when adding a program
- Show/Hide Instructions adds time to interval
- App defaults to unused workout
- Cannot permanently skip to end of timed activity
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- Intervals revert to previous settings
- App won't remember order of custom circuit interval programs
- Blank screen after download
- Cannot get program to open
- Cannot see bottom of screen on questionnaire
Requested features
5 requests- Increase repetitions to 20
- Streamline adding intervals
- Make it possible to hide unused workouts
- Add music integration or option
- Provide visual instructions for moves
In-app purchases
Core
- Monthly$1.991 Month
- Yearly$9.991 Year
- Lifetime$14.99
Interval Flow
- 3 Month$4.993 Months
- 1 Month$9.991 Month
- 1 Month, 3 day trial3 Days trial$9.991 Month
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- Annual7 Days trial$14.991 Year
- 1 Year discounted$25.951 Year
- 1 Year, 3 day trial3 Days trial$39.991 Year
- 1 Year$39.991 Year
- 1 Year Intro month1 Month trial$39.991 Year
- Free Lifetime subscriptionFree
- Lifetime$24.99









