Boin - Bust Care Exercise & Progress Tracker
Boin is a small routine keeper for people who want a few minutes of chest and posture work each day and an honest record of how things change over time. It walks you through four short exercises with a countdown for each, so the whole session takes about three minutes and you never have to wonder what comes next.
Alongside the exercises you can log your top bust and under bust measurements in centimetres, keep front and side photos, and check a calendar that shows which days you completed the routine. Seeing the dates and numbers laid out together makes it easier to stay consistent and to judge progress calmly instead of from memory.
Everything you enter, including photos, stays inside the browser you are using. There is no sign-up and nothing is uploaded, which matters for a topic that most people prefer to keep to themselves.
The app runs entirely in your browser. What you enter is saved only on this device.
How to use Boin
- Read and accept the note on first launch. The web version shows a short disclaimer the first time you open it. It explains that Boin is a personal record tool and not medical advice.
- Start today's exercise. On the home screen tap Start Exercise. Each of the four exercises has a description, the muscles it targets and a timer you can start or pause.
- Work through the four moves. Prayer Pose (45 seconds), Wall Push-ups (45 seconds), Chest Opening Stretch (30 seconds) and a gentle Lymph Massage (60 seconds). Finishing all of them marks the day as complete.
- Add a measurement. Open the measurement tab and enter top bust and under bust in centimetres. Boin shows the difference and an estimated cup size based on it.
- Take or choose a progress photo. In the photo tab pick front or side view, then choose an image from your device or use your camera if your browser offers it. The photo is saved in this browser only.
- Compare before and after. Once you have two or more photos from the same angle, use the before and after slider to look at an older and a newer picture side by side.
- Check the calendar. The calendar shows the days you exercised, your monthly completion rate, this week's count out of seven days, your total sessions and the total time spent.
Features
- Four guided exercises with individual timers, about three minutes in total
- Day streak counter and a calendar of completed days
- Monthly completion rate, weekly count and cumulative time
- Top and under bust measurements in centimetres with the difference calculated for you
- Estimated cup size from the measurement difference
- Front and side progress photos stored privately in the browser
- Before and after slider for photos taken from the same angle
- Option to delete all exercise records, photos and measurements at once
Measuring, photographing and exercising with realistic expectations
How bust measurements work
Two numbers are used. The under bust is measured snugly around the ribcage directly below the breasts. The top bust is measured around the fullest part of the chest, with the tape level all the way round and not pulled tight. The cup letter comes from the difference between the two, not from either number alone.
Boin uses steps of 2.5 cm, a common convention in Japanese and many European sizing systems: under 7.5 cm is AA, 7.5 to 10 cm is A, 10 to 12.5 cm is B, and so on. Brands and countries label sizes differently, so treat the letter as a rough guide for your own tracking rather than a shopping size.
Getting consistent numbers
Small changes in method can move a measurement by a centimetre or more. Measure at the same time of day, wearing the same thing or nothing, standing upright with arms relaxed and breathing out normally. Hormonal cycles can change breast volume noticeably during the month, so comparing readings taken at the same point in your cycle gives a fairer picture.
Taking comparable photos
Use the same spot, the same distance from the camera and similar lighting each time. Daylight from a window to the side is kinder and more consistent than a ceiling light. Keep your posture and arm position the same, and take both a front and a side view. A weekly or fortnightly photo is usually enough; daily photos mostly show noise.
What exercise can and cannot do
Breast tissue itself is made of glands, connective tissue and fat, not muscle, so no exercise directly enlarges it. What exercises like wall push-ups and palm presses do is work the pectoral muscles that sit underneath, and stretches that open the chest can help counter a rounded, hunched posture. Stronger chest and upper back muscles and a more upright stance can change how your chest looks and how clothes sit, which is a realistic and worthwhile goal.
Go gently. Stop if anything hurts, and if you notice a lump, skin change, pain or discharge, see a doctor rather than tracking it yourself.
Frequently asked questions
Where are my measurements and photos stored?
Only in this browser on this device. Records are kept in the browser's local storage and photos in its built-in database. There is no account and nothing is sent to a server. Clearing your browser's site data, or using a private window, will delete them, and they will not appear on another computer or phone.
Can other people see my photos?
Not through Boin, because they never leave your device. Anyone who uses the same browser profile could open the page and see them, so use your own profile or device.
Is the cup size accurate?
It is a simple estimate from the difference between your two measurements in 2.5 cm steps. Real bra sizing varies by brand and region, so use it to follow your own trend rather than to buy underwear.
How long does the daily routine take?
The four timers add up to three minutes. You can pause a timer, and you can leave the session if you need to stop.
What does the phone app have that the web version does not?
The iPhone and Android app can send a daily exercise reminder and a weekly photo reminder. The web page cannot send notifications, so you need to remember to open it yourself.
Can I move my records from the web to the app?
No. The web version and the app keep separate data, and there is no import or sync between them.
Limitations of the web version
- No reminder notifications on the web
- Data stays in one browser and is lost if site data is cleared
- No backup, export or sync between devices
- Measurements are entered in centimetres only
Disclaimer
Boin is a personal routine and record-keeping tool. It is not a medical device and does not provide medical advice, diagnosis or treatment. Results vary between individuals and are not guaranteed. Stop exercising if you feel pain, and consult a doctor or healthcare professional if you have any concerns about your health.
Phone app
Boin is also available as an app for phones and tablets: