Mindfulness deep breathing induction timer (compatible with 4-7-8 breathing method, etc.) | ZeroTools

This page is a timer that guides breathing timing using on-screen seconds and circle movements. First, select a preset in "Select breathing method" on the right, and press "Start session" in the center.

The initial selection is Box Breathing. The seconds are fixed, and there is no function for users to freely input the lengths of inhale, hold, and exhale.

Use the display as a breathing guide; there is no need to forcefully match your body to the numbers on the screen.

Box Breathing is a 16-second setting where one cycle consists of a 4-second inhale, 4-second hold, 4-second exhale, and another 4-second hold.

The circle expands while inhaling, shrinks while exhaling, and maintains its size during the two breath holds. The 4-7-8 breathing method is a 19-second cycle with a 4-second inhale, 7-second hold, and 8-second exhale, with no breath hold in the latter half.

If the 7-second breath hold is uncomfortable, you do not need to continue using that setting.

Deep Breathing is a 10-second cycle with a 5-second inhale and 5-second exhale, and has no breath-holding phase. It is an option when you want a display that does not include breath holding.

However, none of the settings guarantee safety or comfort for specific individuals. The preset cards clearly state the seconds for Inhale, Hold, and Exhale, so you can check if it suits you before starting.

The center circle displays the remaining seconds of the current phase and a short English label. The inhaling phase is IN, the exhaling phase is OUT, and both breath-holding phases are HOLD.

Below the circle, it shows "Inhale", "Hold", and "Exhale", and the color also changes according to the phase. You do not need to memorize just the numbers; you can check the phase name and the expansion and contraction of the circle together.

In the inhale phase, the circle expands from a small state, and maintains its size during the breath hold after inhaling. In the exhale phase, it shrinks back to its original size, and maintains a small state during the breath hold placed after exhaling in Box Breathing.

Since Deep Breathing and the 4-7-8 breathing method do not have a final breath hold, the phase moves to the next inhale phase after the exhale phase ends.

There is also a pale colored display on the outside of the circle, but this is not a mechanism to read the physical state of the body.

The remaining seconds switch to the seconds set for that phase the moment each phase is entered, and decrease roughly every 1 second.

For example, in the 4-7-8 breathing method, it starts from 4 in the inhale phase, then shows 7 for the breath hold, followed by 8 for the exhale phase.

This is a guide that proceeds according to the selected setting, not numbers that detect actual breathing. Avoid forcefully inhaling or exhaling to chase the seconds, and if it becomes difficult, return to your natural breathing.

When you press "Start session", the countdown begins from the inhale phase of the currently selected preset. If you want to stop halfway, you can press "Pause" in the same position.

During a pause, the updates for remaining seconds, elapsed time, and the number of completed cycles stop, and pressing it again resumes from the remaining seconds of the same phase.

However, as the circle's scaling factor returns to 1 during a pause in this implementation, it does not remain fixed exactly at its visual expanded size.

Pressing the circular "Reset" on the left stops the timer and returns it to the starting seconds of the inhale phase for the selected preset (e.g., 4 seconds for Box Breathing, 5 seconds for Deep Breathing).

At the same time, the number of cycles and elapsed time are reset to zero. For example, if you reset halfway through Box Breathing, you can start over from the first 4-second inhale instead of the halfway phase.

Selecting a different preset card also initializes the ongoing state and the two counters. Even if you choose the 4-7-8 breathing method immediately after 3 cycles of Deep Breathing, those 3 cycles are not carried over to the new setting.

The number of cycles increases by 1 when one full pass of all phases of the selected setting is completed. For Deep Breathing, one cycle finishes after a 5-second inhale and 5-second exhale; for the 4-7-8 breathing method, it is a 4-second inhale, 7-second hold, and 8-second exhale.

In Box Breathing, it is counted as one cycle after the final 4-second hold finishes. This number is a guideline for usage and is not the number of breaths measured by a sensor.

The "Chime sound when switching" setting on the right remains enabled by default. When enabled, it plays an alert tone generated via the browser's Web Audio API at session start, when resuming after a pause, and upon switching breathing phases.

If you turn this switch off, you can practice silently by following the animated circle, phase indicator, and numerical countdown.

The session startup logic no longer unconditionally instantiates an AudioContext, allowing visual breathing routines to start or resume even if the browser lacks Web Audio support or audio initialization fails.

The chime function safely returns early when muted and catches audio constructor errors without interrupting the visual session. However, the underlying phase intervals still rely on standard one-second callback intervals that remain subject to cumulative drift, and no comprehensive audio resource lifecycle cleanup or phase redesign is implemented.

The timer is intended purely for relaxation and pacing, providing no medical or health safety guarantees, and audible output remains subject to device volume settings and browser autoplay policies.

The chime uses the same sound made by layering multiple sine waves for each phase; it does not have distinguishing pitches like a higher tone for inhale and a lower tone for exhale.

The 528Hz frequency and its overtones used are merely auditory cues, and this timer does not verify, measure, or guarantee any therapeutic effects.

Since you cannot reliably determine what the next phase is by sound alone, please also check the text on the screen when you want to know the phase.

This is not a feature that guarantees use with closed eyes or operation relying solely on sound. You can switch to mute if you dislike sounds or want to be considerate of your surroundings.

The elapsed time on the screen shows the seconds counted during the session in a minutes and seconds format. It does not increase during a pause and advances again after resuming.

Along with the number of completed cycles, this display is for checking how long you have continued this session. There is no field to input an end condition like 5 minutes or 10 cycles in advance, and there is no function to stop automatically at a set time.

Please press pause or reset when you want to stop.

Internally, the seconds are updated by adding a 1-second callback in the browser. Because it does not cross-reference real time with an independent clock or physical measurement device, strict precision down to the second or millisecond is not guaranteed.

If you move the tab to the background or if the device enters power-saving mode, the processing interval will be delayed, and the displayed elapsed time will lag behind actual elapsed time.

Keeping the page visible makes it easier to check if you are using it while monitoring the timing, but do not treat it as a precision instrument even when displayed.

There is no function to save or export the preset seconds, completion count, or past usage history. Reloading the page returns the session display to its initial state.

It also does not measure breathing, heart rate, or blood pressure using cameras, microphones, or wearable devices. Since there is no function to automatically adjust the seconds according to the user's condition, please stop using it and return to normal breathing if the provided settings do not suit you.

This timer is a tool to signal fixed seconds visually and audibly, and it does not diagnose health conditions or measure therapeutic effects.

Names like Box Breathing or 4-7-8 breathing method simply represent the time distribution on the screen; this tool does not prove that they are clinically effective for specific diseases, insomnia, anxiety, or blood pressure.

Prioritize your own ease of breathing over the on-screen instructions, and do not forcefully deepen your inhalations and exhalations or continue uncomfortable breath holds.

For example, if a 7-second breath hold is painful, an 8-second exhale is too long, or you feel dizziness, shortness of breath, or anxiety, please pause or stop using it immediately and return to natural breathing.

Even with the Deep Breathing preset, which has no breath hold, there is no need to push yourself to match the 5-second display. Breathing and relaxation practices are not a substitute for medical care, so consult a medical professional if symptoms persist or if you have concerns about your health.

General concepts and safety precautions for breathing methods can also be referenced in "Relaxation Techniques: What You Need To Know" by the NCCIH and "Breathing exercises for stress" by the UK NHS.

These encourage not forcing breaths and not delaying medical care, but their guidance should not be confused with clinical validation of the specific presets on this page.

The seconds on this page are strictly ZeroTools' fixed presets and not medical instructions for individuals.