Why your phone's calories burned is a polite estimate, not a fact
Your phone shows a tidy calories-burned number, but it is only a guess with a wide error band. You can still use it in Burnie without trusting it like gospel or throwing it away.
You finish a walk and your phone says you burned 482 kcal. It feels like a fact. It looks like a fact. It is not a fact. It is a polite estimate. That number is your phone doing maths on your steps and your weight, and the maths comes with a wide error band. This article is about your relationship with that number. You do not have to trust it like gospel. You do not have to dismiss it either. There is a kinder middle path, and Burnie is built for it.
How wide the error band really is
Scientists tested seven popular wrist-worn devices against a gold-standard lab machine. The result was blunt. No device got energy expenditure within 20 percent of the truth. The median error ranged from about 27 percent on the best device up to 92 percent on the worst. That is not a small rounding error. That is a wide band. Phones do a little better on raw step counting, but they still undercount. One study found iPhones underestimated daily steps by about 12 percent, mostly because people do not always carry the phone. So when your phone says 482 kcal burned, the honest reading is: somewhere between maybe 350 and maybe 600. The number is not wrong. It is approximate.
My phone's calories-burned number is exact, so I can eat those calories back.
mostly falseMostly false. The number is an estimate with a wide error band, so eating it all back can quietly undo your deficit. The maths does not support treating it as exact.
Three ways to read the same number
How to use the estimate honestly inside Burnie
The bottom line
Your phone's calories-burned number is a polite estimate, not a fact. It comes with a wide error band, often 20 percent or more. Burnie still takes that number from your phone or Android Health Connect, because a noisy guide is better than no guide, and you can always override it yourself. Read it for the weekly trend, never eat it all back, and remember your BMR is the bigger slice. That is the kind middle path between trust and dismiss.