Meditation Timer

Meditation plan

Preset: {{ presetLabel }} Interval {{ interval_min }} min Prep {{ prep_s }} s Bells {{ totalChimes }}

Preset:

Choose 10, 15, 20, zazen 25, 30, open-ended, or Custom.

Session length:

Enter minutes; use 0 when you want to stop the sit manually.

min

Length slider {{ session_min }} min

Countdown:

Enter seconds between pressing Start and the opening cue.

Setup slider {{ prep_s }} s

Interval:

Enter minutes between interval bells, or 0 for start/end cues only.

min

Interval slider {{ interval_min }} min

Start bells:

Use a whole number; 0 skips the opening chime.

Start cue count {{ start_bells }}

Interval bells:

Use a whole number per marker; 0 silences interval chimes.

Interval cue count {{ interval_bells }}

End bells:

Use a whole number; 0 keeps the ending silent.

End cue count {{ end_bells }}

Audio volume:

Chime loudness {{ audio_volume }}%

Set 0-100%; current volume is shown above the slider.

Tone frequency:

Enter Hz; 440-1200 is typical for meditation chimes.

Tone slider {{ beep_hz }} Hz

Tone length:

Enter milliseconds per chime; minimum 40 ms.

Duration slider {{ beep_ms }} ms

Bell gap:

Enter milliseconds between chimes; minimum 60 ms.

Gap slider {{ bell_gap_ms }} ms

Vibrate on chime:

Turn on for haptic cues; unsupported browsers do nothing.

Prevent screen sleep:

Useful for longer sits; browser support varies.

Visual flash:

Turn on to pair every bell cue with a brief visual pulse.

Visual flash length:

Enter milliseconds per pulse; minimum 40 ms.

Flash slider {{ visual_flash_ms }} ms

#	Event	Offset	Local time	Chimes	Copy
{{ r.idx }}	{{ r.label }}	{{ r.offsetDisplay }}	{{ r.local }}	{{ r.chimes }}
No events. Adjust settings above.

Field	Value	Copy
{{ r.label }}	{{ r.value }}
No stats to show.

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A meditation timer is less about ringing an alarm and more about protecting a quiet boundary. The clock gives the sit a clear beginning and ending, so attention does not keep returning to the question of how much time is left. For solo practice, that boundary can reduce clock-checking. For a class, group sit, or retreat period, it keeps everyone aligned without a spoken interruption.

Timed practice usually has four timing ideas: a short preparation period, the sitting start, optional interval cues, and a closing cue. The preparation period gives you time to settle the device, adjust posture, and stop handling the screen before the first bell. Interval cues divide a longer sit into smaller stretches, which can help with posture checks, walking transitions, or tradition-specific timing. The closing cue marks the planned finish for fixed sessions; open-ended practice replaces that fixed finish with a manual stop.

More cues do not automatically make a better session. A dense bell plan can become the thing you attend to, especially in a short sit. A sparse plan can be useful when the goal is uninterrupted attention, while a few interval bells can help when you are learning a new duration, guiding a room, or matching a form such as a 25-minute zazen period with five-minute markers.

Meditation timing is easiest to check when preparation time, sitting time, interval cues, and the closing cue are kept separate.

The main mistake is treating a timer as proof that the practice went well. A timer can keep the room quiet, make cues predictable, and prevent a session from running long, but it cannot judge attention, relaxation, posture, mood, or mental health. It also depends on the device in front of you. Browser sound, vibration, and screen-awake behavior can change when a phone is muted, a tab is backgrounded, or the screen locks.

How to Use This Tool:

Start with the timing plan, then check the cue behavior before relying on it for a quiet room or group session.

Choose a Preset such as 10 min, 15 min, 20 min, Zazen 25, 30 min, Open-ended, or Custom. The summary should update with the preset label, planned length, interval status, prep seconds, and total bells.
Set Session length. A positive value creates a fixed sit with a possible end bell. A value of 0 creates an open-ended sit that you stop manually.
Set Countdown when you want quiet setup time before the opening cue. During a run, the live ring changes to the Settle phase before sitting time begins.
Set Interval if you want recurring bells during the sit. If the Session Schedule shows no interval rows, use a positive interval, a positive interval bell count, and an interval shorter than the fixed session.
Open Advanced to tune start, interval, and end bell counts, audio volume, tone frequency, tone length, bell gap, vibration, screen-awake behavior, and visual flash length.
Use Test tone after changing audio or cue settings. If the room needs silence, set audio volume to 0 and rely on visual flash or supported vibration instead.
Press Start, then use Pause or Stop as needed. Review Session Schedule, Bell Cue Timeline, Chime Distribution, Session Stats, and JSON before or after the sit.

For a first pass, keep the plan simple: a short countdown, clear start bells, no interval bells for a short sit, and a closing cue you can hear on the actual device.

Interpreting Results:

Session Schedule is the main audit view. It lists each cue in order with its event name, offset, local time, and chime count. Check this table when you want to catch a missing end bell, an interval that lands too close to the finish, or a cue count that would be too loud.

Bell Cue Timeline shows where each cue falls across elapsed minutes. Use it to spot crowded cue plans. Chime Distribution separates start, interval, and end chimes, which makes it easier to see whether interval bells dominate the session.

Session Stats is best for the current state: Status, Session (min), Active session (min), Elapsed (s), Remaining, Next event, Total events, and Total chimes.
Open-ended sessions have no Planned finish and no automatic end bell. The schedule previews recurring interval cues instead of promising an infinite list.
High cue counts mean more interruptions. A plan with many interval chimes may be useful for instruction, but it can be distracting for silent practice.
Browser cues are not guaranteed alarms. Test sound, vibration, visual flash, and screen-awake behavior on the same device before using the timer for a class or retreat block.

Treat the live ring and Session Stats as the current run state, and treat the schedule and charts as the planned cue pattern. If they do not match your intention, adjust the timing fields before starting again.

Technical Details:

A meditation cue schedule is anchored to the sitting start, not to the moment the Start button is pressed. Countdown seconds move the sitting start into the future. Once sitting time begins, cue offsets are measured from that start point: zero for the opening cue, repeated minute offsets for interval cues, and the full session length for the closing cue.

Fixed sessions and open-ended sessions differ in one important way. A fixed session has a known duration, so interval cues must occur before the end and the closing cue can be placed exactly at the finish. An open-ended session has no finish time, so interval cues are shown as a finite preview and the Stop button becomes the ending action.

Formula Core

Let M be Session length in minutes, P be Countdown in seconds, and G be Interval in minutes. The timing core is:

S = M \times 60

T_{0} = T_{press} + P

I_{k} = k \times G \times 60, 1 \leq k, I_{k} < S

Symbol	Meaning	Displayed relationship
S	Fixed session seconds	Feeds Active session (min), Remaining, and planned finish time.
T₀	Sitting start time	Appears as Start time (local) after the countdown is applied.
I_k	k-th interval offset	Appears as Interval rows in Session Schedule and Bell Cue Timeline.

Cue Inclusion Rules

Cue type	Included when	Offset rule
Start bells	Start bells is greater than 0.	Offset 00:00 from the sitting start.
Interval bells	Interval and Interval bells are both greater than 0.	Every interval offset before the fixed-session finish.
End bells	Session length and End bells are both greater than 0.	Exactly at the fixed session length.
Open-ended interval preview	Session length is 0 and interval cues are enabled.	Recurring interval offsets are previewed up to three hours or 60 interval cues.

Example: a 25-minute session with a 5-minute interval has S = 1,500 seconds. Interval offsets fall at 300, 600, 900, and 1,200 seconds. The 1,500-second point is the end cue, not an interval cue, because fixed-session interval bells must occur before the finish.

Repeated chimes use the selected tone length and bell gap. Audio volume at 0 mutes the tone while still allowing visual flash and supported vibration. Tone frequency changes pitch, tone length changes each chime duration, and bell gap separates repeated chimes so a three-bell start cue does not collapse into one long sound.

Limitations and Privacy:

The timing math is deterministic, but the cues still depend on browser and device behavior. Use the timer as a practice aid, not as medical, mental-health, sleep-treatment, or safety-critical equipment.

Sound may be blocked, muted, delayed, or quieter than expected depending on browser audio policy, system volume, Bluetooth devices, and silent mode.
Vibration works only on supported devices and browsers. Unsupported browsers simply skip the haptic cue.
Screen-awake behavior depends on wake lock support and can be released by the browser, operating system, low battery mode, or tab visibility changes.
The timer does not ask for a microphone, camera, location, account login, or meditation journal. Its visible schedule and exports are built from the current timing settings and run state.

Worked Examples:

Short silent sit. Choose 10 min, keep Interval at 0, use a 3-second Countdown, and set 3 start bells and 3 end bells. Session Schedule should show Start ×3 at 00:00 and End ×3 at 10:00. Session Stats should show Session (min) as 10, Total events as 2, and Total chimes as 6.

Zazen-style timing. Choose Zazen 25. With the default 5-minute interval, Session Schedule should place interval cues at 05:00, 10:00, 15:00, and 20:00, with the end cue at 25:00. Chime Distribution should show start and end chimes separated from the four interval chimes.

Open-ended practice. Choose Open-ended or set Session length to 0 with a 5-minute interval. Session Stats should show Active session (min) as Open-ended and Planned finish (local) as a dash. Session Schedule previews interval cues, and the session continues until you press Stop.

Missing interval cue. A 10-minute session with a 10-minute interval does not create a 10:00 interval row because that offset is the finish boundary. Set Interval to 5 minutes or increase Session length if you want an in-session cue.

FAQ:

Can I use this for zazen timing?

Yes. The Zazen 25 preset sets a 25-minute session with five-minute interval cues, then you can adjust bell counts, countdown, audio, vibration, and visual flash for your room.

Why did my interval bells disappear?

Interval rows need a positive Interval value and a positive Interval bells count. In fixed sessions, interval offsets must fall before the end time, so an interval equal to the session length will not appear as a separate interval cue.

Why is there no planned finish in open-ended mode?

Open-ended mode sets Session length to 0, so there is no fixed finish time and no automatic end bell. Use Stop when the sit is complete.

Why did sound or vibration not work on my phone?

Mobile browsers and operating systems can block sound, vibration, or wake lock behavior when the device is muted, locked, backgrounded, or unsupported. Use Test tone and check Visual flash before relying on the session.

Does the timer measure meditation quality?

No. It reports timing, cues, elapsed time, remaining time, total events, and total chimes. It does not assess attention, calmness, mental health, or sleep quality.

Glossary:

Prep countdown: The setup time between pressing Start and the sitting start.
Sitting start: The zero point for schedule offsets, after any prep countdown.
Interval bell: A recurring cue placed at the selected minute spacing during the sit.
Open-ended session: A session with no fixed finish time, no planned end bell, and a manual Stop action.
Wake lock: A browser feature that can request the screen to stay awake during an active sit when supported.
Haptic cue: A vibration cue from supported devices, used as a quiet alternative or companion to sound.

References:

Meditation and Mindfulness: Effectiveness and Safety, National Center for Complementary and Integrative Health, June 2022.
OscillatorNode, MDN Web Docs, August 27, 2025.
Vibration API, MDN Web Docs, April 11, 2024.
Screen Wake Lock API, MDN Web Docs, July 3, 2025.