The QardioBase X is a pricey smart scale that accurately measures your weight, body fat, and many other body composition metrics, and lets you track your results from your phone.
With support for 13 trackable body composition and health metrics, plus modes for weighing babies, luggage, and pets, the affordable Wyze Scale X is the best smart scale for most people.
It has some limitations, but for less than $20, the Wyze Scale S is one of the most affordable smart scales for tracking your weight and body composition metrics over time.