You know all those calories your fitness tracker says you burned today, they may not be as accurate as you think.
A new study out of Iowa State University tested eight different activity monitors against a portable metabolic analyzer for accuracy.
Researchers found most trackers were reasonably accurate when it came to calorie-burn estimates but some more than others.
The most accurate devices of the eight tested were the Bodymedia Fit, followed by the FitBit Zip and FitBit One.
Other devices tested include: Jawbone up, Actigraph, Directlife, Nike FuelBand and Basis Band.