Smart scales, which use a method called bioelectrical impedance analysis (BIA), are becoming more popular for tracking body composition. These devices send a small electrical current through the body to estimate the proportions of different tissues. Since muscle and water conduct electricity well, while fat and bone resist it, the speed at which the current travels helps determine the body’s composition. Dr. Vijay Nayar from Healthium Clinics explains that the scales calculate the amount of each tissue based on how easily the current moves through the body. Dr. Naveed Asif, a general practitioner at The London General Practice, emphasizes that muscle mass is crucial for overall strength and metabolic health, and that measuring visceral fat—hidden fat around organs—can indicate a higher risk of heart disease and diabetes. Several smart scales stand out in 2026 for their features and accuracy. The Withings Body Smart Bathroom Scale offers a wide range of metrics, including weight, muscle, body fat, visceral fat, water, bone, and heart rate, along with weather and air quality reports. The Beurer BF451 Body Analyser Scale is a more affordable option that provides detailed data such as protein percentage and active metabolic rate. The Renpho Morphoscan Nova includes a retractable handle with thumb sensors and a visual map of body fat and muscle distribution. The Salter Body Insight Smart Scale offers similar data at a lower price, while the Eufy Electronic Smart Scale C2 is great for small spaces and provides impressive data for its cost. The Omron Viva Smart Scale is praised for its ease of use, and the Garmin Index S2 Smart Bathroom Scale works well with Garmin fitness trackers. The A&D Medical UC-502 Weighing Scale is a simple digital scale suitable for weighing luggage or other items. Despite their popularity, smart scales are not 100% accurate and typically have a margin of error between 3% and 8%. To get the most accurate readings, users should measure at the same time each day, ideally first thing in the morning after using the bathroom and before eating or drinking. Dr. Nayar advises against measuring after exercise or large meals, as these can affect hydration levels and impact the results. Users should stand on the scales with clean, dry feet and remain still during the measurement. Some models, like the Renpho and Salter scales, require users to hold their arms at a 45-degree angle away from the torso for more accurate readings. The accuracy of smart scales can also vary between men and women. Dr. Asif notes that modern smart scales may adjust for gender differences to improve accuracy. Dr. Nayar adds that women may experience changes in fluid retention due to hormonal fluctuations, which can affect body fat percentage readings. Premenopausal women are advised to track their readings at the same point in their menstrual cycle to better understand long-term trends in their body composition.