Documentation

Getting Started

Circuit Timer lets you build custom interval workouts and run them with voice countdown, alarms, haptics, and Live Activities. Here's how to get going.

1. Open the app — you'll see the home screen with your circuits. A default HIIT circuit is included to get you started.
2. Tap the play button on any circuit card to start it immediately.
3. Tap the card itself to edit the circuit, change intervals, adjust alarms, or customize colors.
4. Create a new circuit by tapping the + button at the top of the home screen.

Building Circuits

A circuit is a sequence of intervals that repeat. Each interval has a name, duration, and color.

Intervals

Add intervals to your circuit and give each one a name (e.g. "Work", "Rest", "Sprint") and a duration. Intervals play in order from top to bottom. Drag to reorder them.

Repeat Mode

Control how your circuit loops:

• Count — repeat a fixed number of times (e.g. 8 rounds).
• Time — repeat until a total time is reached (e.g. 20 minutes).

Skip Last Interval

When using count mode, enable "Skip Last Interval" to drop the final rest period. For example, in a Work/Rest circuit with 8 rounds, you'll get 8 work intervals and only 7 rest intervals.

Colors

Each circuit has an accent color that appears on its card, progress ring, and timeline. Choose from 8 colors: Coral, Amber, Lime, Teal, Sky, Indigo, Violet, and Rose. Individual intervals can also have their own color for easy visual identification.

Templates

Save an interval configuration as a template to reuse across circuits. When adding intervals, tap "From Template" to pick from your saved templates.

Running Timers

Player Controls

The full-screen player shows the current interval name, time remaining, and a progress ring. Controls at the bottom:

• Play/Pause — start or pause the timer.
• Previous/Next — skip to the previous or next interval.
• Stop — end the circuit and return to the home screen.

Prepare Countdown

Enable "Prepare" in circuit settings to get a countdown before the first interval starts. This gives you time to get into position. Tap the Next button during prepare to skip it.

Auto-Start

When auto-start is on, intervals advance automatically. Turn it off to pause at each interval boundary — useful for exercises where you need setup time between sets.

Multiple Timers

You can run multiple circuits at the same time. Each appears as a compact card on the home screen showing its current state. Tap a running card to open its full-screen player.

Interactive Timeline

The timeline bar below the progress ring shows your entire circuit at a glance. The current interval is highlighted and scrolls to stay centered. Tap any segment to jump directly to that interval.

Alarms & Haptics

Alarm Sounds

Choose from 24 alarm sounds across five categories: Digital, Tones, Bells & Gongs, Alerts, and Fun. The alarm plays at each interval boundary and when the circuit finishes. Set to "None" for silent operation.

Alarm Duration

Control how long the alarm rings at each interval change. A single play is good for short intervals; longer durations ensure you hear it during intense exercise.

Haptic Vibration

Haptics provide a physical tap at each interval boundary. Combined with alarms, you get both audio and physical notification. Haptics work even in silent mode.

Voice Countdown

Voice countdown announces interval changes and counts down the final seconds so you can focus on your form instead of watching the screen.

Countdown Modes

• Off — no countdown ticks or voice.
• Sound — audible tick sounds in the final seconds before each interval change.
• Voice — spoken countdown numbers plus interval name announcements.

Countdown Window

Choose how many seconds before each interval change the countdown begins: 3, 5, or 10 seconds. This applies to both sound ticks and voice announcements.

Voice Announcements

When voice mode is active, the app announces the name of each new interval as it begins. This is especially helpful for circuits with many different exercises.

Live Activities

When a circuit is running, a Live Activity appears on your lock screen and in the Dynamic Island. It shows:

• Current interval name and color
• Time remaining in the current interval
• Circuit name and round progress

The Live Activity updates automatically at each interval change. If you're running multiple circuits, the primary circuit's Live Activity is shown. Live Activities also mirror to Apple Watch Smart Stack when available.

Apple Watch

The Apple Watch app runs circuits independently — no phone needed. Your circuits sync via iCloud so they're available on your wrist.

Watch Features

• Standalone playback — start and run circuits entirely on the watch.
• Haptic alerts — feel interval changes, countdown ticks, and circuit completion on your wrist.
• Alarm sounds — hear the same alarm sounds from your watch speaker.
• Workout tracking — records to Apple Health as an active workout with heart rate and calories.
• Remote control — when a timer is running on your iPhone, your watch shows it and lets you control it.

Smart Stack

When a circuit is running on your iPhone, it mirrors to the Apple Watch Smart Stack via Live Activities. You can see your timer status at a glance without opening the watch app.

iCloud Sync

Circuits sync automatically between your iPhone, iPad, and Apple Watch via iCloud. Changes appear on all devices within seconds when connected to the internet.

To sync, sign in to the same iCloud account on all devices and make sure iCloud Drive is enabled. No additional setup is required.

Apple Health

Completed circuits are automatically saved to Apple Health as workouts. Each session records:

• Workout type (HIIT / functional training)
• Duration and active energy burned
• Heart rate data (when running on Apple Watch)

Grant Circuit Timer access to Apple Health when prompted on first launch. You can manage permissions later in Settings > Health > Circuit Timer.

Siri & Widgets

Siri Shortcuts

Start any circuit with Siri. Say "Hey Siri, start my HIIT workout in Circuit Timer" and the circuit begins immediately. Circuits are registered as App Shortcuts and appear in the Shortcuts app.

Quick Start Widget

Add the Quick Start widget to your home screen for one-tap circuit launch. Long-press your home screen, tap the + button, search for Circuit Timer, and add the widget.

Workout History

Every completed circuit is recorded in your workout history. View past sessions grouped by date, including:

• Circuit name and total duration
• Number of intervals completed
• Date and time

The stats view shows your workout streaks and overall activity. History is stored locally and available on the free tier.

Plans & Pricing

Circuit Timer is free to download. Two one-time upgrades are available — no subscriptions.

Purchases are one-time and tied to your Apple ID. Restore anytime via Settings > Your Plan > Restore Purchases.

FAQ