BMI scales using bioelectrical impedance analysis (BIA) provide reasonably accurate estimates for body composition when used consistently under similar conditions. While not as precise as DEXA scans, they offer excellent value for tracking trends over time. Accuracy typically ranges from 85-92% compared to clinical methods.

Smart scales use bioelectrical impedance analysis (BIA) by sending a low-level electrical current through your body. Since muscle tissue contains more water and conducts electricity better than fat tissue, the scale can estimate body composition based on resistance patterns. For best results, weigh yourself at the same time daily, preferably in the morning.

Key features to consider include: accuracy (±0.2 lbs or better), number of body metrics tracked (8-16 measurements), app quality and connectivity (Bluetooth/Wi-Fi), compatibility with health apps (Apple Health, Google Fit), multiple user profiles, build quality, and warranty coverage. Consider your specific needs and budget range.

Both connectivity options have benefits. Bluetooth requires your phone to be nearby during weighing but offers reliable connection. Wi-Fi allows automatic data sync even when your phone isn’t present and enables features like weather forecasts on the scale display. Many modern scales like the Etekcity and Eufy P3 offer both options for maximum flexibility.

Muscle mass specifically measures skeletal muscle tissue, while lean body mass includes all non-fat tissues: muscles, bones, organs, and water. Lean body mass is typically higher than muscle mass alone. Both metrics are valuable for tracking fitness progress, especially for strength training and weight management goals.