QN Scale

QN Scale is an app for bathroom scales that speak the QN protocol. Such scales are sold under the Qingniu, Yolanda and a dozen other names; on the air they usually appear as QN-Scale.

Step on the scale and your weight is already recorded. You find the scale once — after that the app connects on its own while the phone simply lies nearby.

• A chart that follows your finger: pan, pinch and an overview slider under the curve. Press and hold for a marker with the date, the weight and the change since last time.
• 7, 30 and 90 days, or your whole history at once.
• Body composition: the scale measures impedance and the app estimates body fat from it. There is an offset — for when you trust another result more.
• A goal line on the chart and a forecast from the rate of the last thirty days, with the date the goal is reached.
• Apple Health: weight, body fat and BMI go there with your permission, and you can import your history back — duplicates are filtered out.
• The weigh-in reminder arrives only on days when you haven't stepped on the scale yet.
• Russian and English switch inside the app, together with date and number formats.

Your data goes nowhere. The app has no server, no accounts, no analytics and no third-party SDKs — there is not a single network call in its code. Weigh-ins stay on your iPhone, and Bluetooth is used only to talk to the scale.

Body fat is an estimate from impedance, not a measurement: every manufacturer keeps its own closed formula. Watch how the number moves over time rather than its absolute value. The app is not a medical device and is not a substitute for a doctor.