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Ko Interval Timer

by KoAppStudio

4.3 Editor's Rating

Round-based interval timer with voice coaching, achievement badges, and a personal training journal for iPhone.

Last Updated: October 28, 2026

Pricing Model: subscription

Starting Price: $14.99 A Year

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What is Ko Interval Timer?

Ko Interval Timer is an iPhone interval timer app designed for round-based workouts like boxing, HIIT, circuit training, and other interval-focused exercises. Available on the iOS App Store and requiring iOS 16.4 or later, it goes beyond basic countdown functionality by wrapping a flexible timer in features that motivate and track progress.

What distinguishes Ko Interval Timer from simpler alternatives is its integration of voice coaching, achievement badges, training streaks, and a built-in workout journal. Users can create fully custom timers by setting work periods, rest intervals, round counts, and preparation countdowns, then label each phase with its own name.

Three voice coaches, including a Boxing Coach with an optional Funny Mode that delivers humorous motivational comments between rounds, provide real-time encouragement during sessions.

The app includes a workout journal that records every session, with the option to add post-workout selfies, bodyweight tracking, and training notes.

Achievement badges reward milestones, while detailed statistics and training streaks help users monitor consistency and progress over time. All data is stored locally on the device for privacy.

Top Features

Custom Workout Builder

Create fully customizable interval timers by setting work periods, rest times, number of rounds, preparation countdowns, and custom phase names to match your exact training needs.

Voice Coaching with Funny Mode

Choose from three motivating voice coaches that guide you through sessions. The Boxing Coach includes an optional Funny Mode that adds humorous motivational comments between rounds.

Built-In Workout Journal

Record every training session with notes, post-workout selfies, and bodyweight tracking. All entries are stored locally on your device and build a lasting record of your fitness journey.

Achievement Badges and Streaks

Earn badges for training milestones and maintain training streaks that reward consistency. View complete workout history including total training time, rounds completed, and overall activity.

Customizable Alerts and Interface

Choose timer sounds, customize alerts for session start, phase changes, and end bell. Select spoken countdowns, vibration, and visual signals, plus personalize with custom accent colors.

Keep-Screen-Awake Setting

Timer stays visible during workouts without needing to unlock your phone, with a large, readable countdown display for quick at-a-glance time checks.

Pros & Cons

Pros

Unique voice coaching with humorous Funny Mode adds personality to workouts
Comprehensive workout journal with selfies and notes creates lasting training records
Highly customizable timer settings for any round-based workout format
Achievement badges and streaks provide strong motivation for consistency
Clean, modern interface with large countdown display easy to read mid-workout
Privacy-focused with local data storage on device

Cons

iPhone only, no Android version available
Requires iOS 16.4 or later, limiting compatibility with older devices
Screen must remain unlocked during workouts for full visibility

Use Cases

Boxing and Combat Sports Training

Create custom round timers for boxing, kickboxing, or MMA training with rest periods between rounds, using the Boxing Coach voice for authentic fight-style motivation.

HIIT and Circuit Training

Set up high-intensity interval workouts with precise work-rest ratios, track completed rounds, and maintain workout streaks to stay consistent with fitness goals.

Home Workout Routines

Build customized interval timers for bodyweight circuits, yoga flows, or stretching sessions, with voice guidance and a journal to document progress over time.

Personal Training and Fitness Coaching

Design client workout timers with named phases for each exercise, review session history, and track client consistency through training streaks and statistics.

Ko Interval Timer Q & A

Does Ko Interval Timer work on Android?

No, Ko Interval Timer is currently only available for iPhone and requires iOS 16.4 or later. There is no Android version at this time.

Can I use Ko Interval Timer without a subscription?

The app is available free on the App Store, but premium features require an active subscription. Monthly and annual plans are available, though specific pricing details are shown in the app.

Does the timer work when the screen is locked?

The app includes a keep-screen-awake setting so the timer stays visible without unlocking your phone, but for full visibility the screen should remain on during workouts.

Is my workout data private?

Yes, all journal entries, notes, selfies, and bodyweight data are stored locally on your iPhone rather than in the cloud, ensuring your training information stays private.

What is Funny Mode?

Funny Mode is an optional feature for the Boxing Coach voice that delivers humorous motivational comments between rounds, adding entertainment value while still encouraging you to keep training.

Can I customize the sounds and alerts?

Yes, you can choose your preferred timer sounds and customize alerts for the session start, phase changes, and the final bell. Spoken countdowns, vibration, and visual signals are all adjustable.

Our Verdict

4.3

Ko Interval Timer stands out in a crowded field of workout timer apps by combining solid core functionality with thoughtful motivational features.

The voice coaching, particularly the Funny Mode, adds genuine personality that makes training more enjoyable, while the built-in journal and achievement system provide compelling reasons to stay consistent beyond just tracking time.

For iPhone users focused on round-based training like boxing, HIIT, or circuit workouts, Ko Interval Timer delivers excellent value through its customization options and privacy-first approach.

The subscription requirement may deter some users, and the iOS-only availability limits its reach.

However, if you want more than just beeps and countdowns from your interval timer, Ko Interval Timer's coaching, journal, and gamification features make it a worthwhile training companion.

Try Ko Interval Timer