Testing Protocol
We tested 5 fitness trackers under $100 for 2 weeks each, comparing step counts against manual tallies, heart rate against chest straps, and sleep staging against self-reported sleep quality. Battery life was measured with continuous heart rate monitoring enabled.
Best Overall: Xiaomi Smart Band 9 ($49)
At $49, this tracker delivers 95% step accuracy (compared to our reference pedometer), reliable heart rate monitoring within 5 BPM during steady-state exercise, and 14-day battery life. The 1.62-inch AMOLED display is bright and readable in sunlight. Sleep tracking identifies light, deep, and REM stages that correlated with our subjective sleep quality ratings.
Best for Accuracy: Fitbit Inspire 3 ($99)
Fitbit's step algorithm remains the most accurate in our testing—98% accuracy across walking and running. Heart rate is reliable during moderate exercise but lags during intervals (3-4 second delay). The Fitbit app provides the most detailed health insights including stress management scores and menstrual cycle tracking. Battery lasts 10 days.
Best for Battery: Huawei Band 10 ($39)
21-day battery life with continuous heart rate monitoring. The SpO2 monitoring is consistent with pulse oximeter readings within 2%. The main limitation is the companion app, which has fewer third-party integrations and a less polished interface than Fitbit or Xiaomi.
What You're Missing Under $100
Budget trackers lack GPS (phone-dependent for route tracking), advanced metrics like VO2 max estimation, and contactless payments. If you run without your phone, you'll need to spend $150+ for built-in GPS.