Which device has the most accurate step count?

There is no single accurate count — devices use different thresholds. Pick one and trust its trend. The bigger error is double-counting when two devices count the same walk.

Step counts across devices — why your phone, watch and Fitbit disagree

Two devices rarely agree on your step count, and it is worth knowing that there are two separate reasons for that, not one.

Reason one: different thresholds

A step is not a physical constant — each device decides what wrist or hip motion counts as one, and where it draws the line. A device worn on the wrist sees arm swing a hip-worn phone does not; a sensitive algorithm counts fidgeting, a conservative one misses a slow amble. So even measuring the same walk, two devices legitimately return different totals, and neither is “wrong” — they are answering a slightly different question about what a step is.

Reason two: double-counting

The bigger discrepancy comes from wearing two counters. An iPhone in your pocket and a Watch on your wrist both count the same walk, and any total that adds them roughly doubles it — which is why a raw Apple Health export reads higher than the Health app, and why Fitbit-plus-phone totals inflate. This is a de-duplication problem, not a threshold one, and it is resolved by picking one source per period rather than summing.

Which number to use

For a personal trend, pick one device and stay with it — its threshold bias is constant, so its numbers are comparable to each other even if they differ from a friend’s tracker. For a daily total from a multi-device setup, use the platform’s de-duplicated figure, not a sum. Absolute step counts are not portable between brands; their trends are.