If you have a modern smartphone, you may not need a dedicated wearable for fitness tracking. A new study has found that mobile apps can be just as accurate as smartbands when it comes to tracking physical activity.

Led by researchers at the Perelman School of Medicine and the Center for Health Incentives and Behavioral Economics at the University of Pennsylvania, the study tested 10 of the top-selling smartphone apps and devices in the U.S.

As part of the test, 14 participants were required to walk on a treadmill for 500 steps and then 1,500 steps, twice each, for a total of 56 trials in total. During their walk, each participant wore a pedometer and two accelerometers on their waist and three wristbands, and carried two smartphones in their pockets — one of which was running three tracking apps, the other just one.

When the researchers counted the steps at the end, there was only a slightly difference in data between the smartphones and the dedicated wearable devices.

"Compared to the one to two percent of adults in the U.S. that own a wearable device, more than 65 percent of adults carry a smartphone," said senior author Mitesh S. Patel. "Our findings suggest that smartphone apps could prove to be a more widely accessible and affordable way of tracking health behaviors."

What's particularly interesting is that the study showed a range of -6.7 to 6.2 percent relative difference in mean step count from the smartphones, while wearable devices differed more with a range of -22.7 to -1.5 percent. While results can vary drastically depending on the make and model of your fitness tracker, then, they tend to be relatively close no matter what smartphone or app you're using.

Some wearables, however — such as the Fitbit One — proved to be very accurate, while others don't offer any noticeable advantage over using only a smartphone. But of course, there are some caveats we should take into account.

The study only focused on six different trackers, and didn't include the latest models. It also didn't include smartwatches. What's more, we must remember that not everybody wants to go running or walking with their smartphone in their pocket, in which case spending money on a dedicated tracker is worth it.

If you don't mind carrying your smartphone, however, that may be all you need.