The step count on your fitness tracker is less accurate than you think

By Sam Downing|

But that might not be such a big deal

"My fitness tracker told me I took exactly 11,567 steps today," you smugly note to yourself before you go to bed. But beware — the true number is probably a lot less.

Fitbit devices have become an increasingly common way to measure health, so researchers from Canada's University of British Columbia (UBC) set out to determine how accurate this data is — particularly when it comes to counting steps.

The team scoured 67 studies and published their findings in the journal JMIR Mhealth Uhealth.

They determined Fitbit's various gizmos deliver an accurate step count only around half the time — with a tendency to overestimate steps taken out in the real world, in a range that varied from 700 to 1800.

The standard daily step count goal is 10,000, so that's a pretty significant difference.

RELATED: Why is 10,000 steps the magic number to walk each day?

The analysis also found Fitbits don't provide wholly accurate measures of energy expenditure, so the number of calories you actually burned during a workout is likely to be less than the number it reports.

A study by another UBC team published in the Journal of Sports Sciences in 2017 found iPhones aren't perfect at counting steps either, with the smartphone's step tally differing from the true number by more than 1300 per day.

But! Just because your step count isn't 100 percent accurate doesn't mean it's useless — assuming you're a regular person, not someone who needs precise numbers for health or research or some other reason.

Think of the step count as a rough guide to track your behaviours. What actions did you take on high-step days — maybe you went for a walk with a friend, or had to park your car at the far end of the shopping centre — and can you repeat them to increase your overall physical activity?

That's more or less the conclusion reached by the authors of the Fitbit study, who also noted that activity trackers are likely to become more accurate in future.

"Our findings do not negate the value of using Fitbit activity trackers in the manner for which the devices were intended, which is for self-monitoring of physical activity patterns and motivating individuals to achieve their physical activity goals," they wrote.

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