My whole family used the RunStar 4e Body Scale, and this affordable scale is great for weight — but let down by inaccurate body composition

TechRadar Verdict

The RunStar 4E delivers accurate and reliable measurements of weight, BMI, and metabolic age. Unfortunately, other metrics related to body fat and muscle were far less accurate, with some measurements deviating up to 30% compared to the RunStar 8E SmartScan Pro. That said, the scale does measure consistently with itself and so can be relied upon for tracking weight loss. Not bad for one of the most budget-friendly smart scales on the market.

Pros

+Simple and effective design
+Easy to operate
+Accurate weight and BMI
+Extra metrics in smartphone app
+Very affordable

Cons

-No syncing with health apps
-Variable results across metrics
-AAA batteries rather than built-in

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RunStar 4E Body Scale: One minute review

The RunStar 4E is an affordable smart scale that costs little more than a standard set of electrical scales. Considering it measures more than 20 different body composition metrics, the low price becomes even more impressive. As you’d expect at this price, there are limitations though, with the inability to measure composition accurately (fat-to-muscle ratios and so on) being the most glaring one.

Despite these shortcomings, everything, from app setup to using the scales, is smooth, straightforward, and wonderfully intuitive. Connecting the scales to the companion app is quick and easy thanks to a robust Bluetooth signal, and the option to create multiple users within the app is a nice touch for a family of my size and stage.

The weight measurement consistently measured around 0.4% more than the pricier RunStar 8E SmartScan Pro, which isn’t a massive deviation. For almost all the other measurements, the RunStar 4E adopts a bioelectrical impedance analysis (BIA) measuring method through four metal sensors located on the top panel of the scale.

BMI measurements were almost identical every single time compared to the 8E SmartScan Pro (probably because it's a mathematical calculation not dependent on the electrodes), but almost all other composition measurements offered up a deviation of between 3 and 30%. For these reasons, it’s not likely to make it into our best smart scales guide. That said, for the price, the RunStar 4E is a respectable set of scales for weight and quick BMI calculation.

RunStar 4E Body Scale: Specifications

RunStar 4E Body Scale: Price and availability

$33.54 / £31.00
Not available in Australia
Budget-friendly smart scale

At $33.54 USD / £31.00 GBP, the RunStar 4E Body Scale is incredibly affordable as far as smart scales go. It might lack full body measurements for fat loss and fitness and muscle gain, but for that pleasure you’ll have to part with a lot more money and shoot for something like the RunStar 8E SmartScan Pro, Withings Body Scan series, or Wyze Scale X.

A comparable option in terms of price and features would be the Vitafit Smart Bathroom Scale, which scored a respectable four stars in our testing. Positives included the easy connection, extremely fast results, and the comprehensive app. Our reviewer had some concerns over accuracy, but overall it’s a solid choice.

The scales are FSA and HSA eligible, which means US users are able to use them in conjunction with designating pre-tax money to be taken from pay and put towards paying medical expenses.

Value score 4.5/5

RunStar 4E Body Scale: Design

LCD display with color graphics
Compact and lightweight design
Powered by 3x AAA batteries

At the heart of the RunStar 4E is a bright LCD display that provides an easy-to-access readout of six metrics: weight, body fat, BMI, muscle mass, body water, and bone mass. The display cycles through these with a few seconds given over to each stat. Unfortunately there’s no way to move to a specific metric using on-device controls, although the full list is available in the accompanying app.

At 11.02 x 11.02 x 0.78 inches and 3.17 pounds, the smart scale is both compact and lightweight. As a result, finding a suitable spot for it in a bathroom or bedroom shouldn’t be a problem. It can also be easily stowed on its side in a cupboard while not in use.

The scale is covered in 6mm tempered glass, which protects against scratches and cracks, neither of which I suffered despite my children doing their accidental best to inflict a dent or two. Underneath you’ll find four anti-slip silicone feet.

Quick and effortless connectivity is via Bluetooth, and power is delivered courtesy of three AAA batteries. USB-C charging would have been better for the environment, but with minimal power required, I don’t envisage getting through too many batteries.

Design Score: 4/5

RunStar 4E Body Scale: Features

22 reportable metrics including weight, BMI, and muscle mass
App supports multiple users

The RunStar 4E boasts an impressive feature set for such an affordable scale, or at least it would be if the extras were more impressive. At its core, the scale is capable of measuring over 20 metrics, including weight, BMI, body fat percentage, body mass, muscle mass, body water rate, bone mass, and visceral fat. Six of these are visible on the smart scale itself, while the full set is reported in the Starfit RunStar app.

To accommodate families, the Starfit app enables users to set up multiple profiles, one for each family member. By entering the height and target weight of each person, the app is able to provide more accurate and informed reporting. The app also tracks measurements over time and plots them on a chart for trend analysis.

Features Score: 4/5

RunStar 4E Body Scale: Performance

Quick results on-device and in-app
Accurate weight, BMI, and metabolic age
Some inaccuracies consistently reported

The first thing to note is that the RunStar 4E is quick. In a matter of seconds the scale is able to measure over 20 different body composition metrics and display them instantly in the app. There’s no waiting around for calculations to be made and zero lag when the display is cycling through the six core metrics.

Weight, as you’d expect, is measured prior to all the body composition elements. Having measured myself hundreds of times, I found that the 4E regularly mismeasured my weight by around 0.4% compared to the RunStar 8E SmartScan Pro and, indeed, my rudimentary pair of digital weight scales. It would be unfair to judge the scales too harshly for this small deviation, especially given the price.

According to research published in the Journal of Medical Internet Research, one study conducted on smart scales shows a median margin of error of around 0.3kgs, so I can forgive it some small deviation. That said, if you’re requiring absolute accuracy, you’ll need to look elsewhere.

BMI was also consistently measured more or less accurately, with deviations of only 0.5%. If you’re only concerned with quick measurements such as weight and BMI, then the RunStar 4E won’t cause you any problems.

Getting into the specifics, musculoskeletal-related measurements using BIA include muscle, muscle mass, and skeletal muscle rates. The first two measured around a 3% deviation from the 8E SmartScan Pro, but it was the skeletal muscle rate which was most concerning, measuring a deviation of nearly 15%.

Unfortunately variable results continue with fat-related metrics. Compared to the SmartScan Pro, body fat percentage, subcutaneous fat, and body fat mass all reported a massive 30% deviation.

Despite comparably poor results on some metrics, it’s worth remembering that most of these are specialized measurements, and to expect too much from a smart scale that costs $33.54 / £31.00 might be a little unreasonable.

That said, it would be preferable for consumers if smart scale manufacturers would only include metrics that they could report on accurately. The RunStar 4E also measures consistently with itself, which means it can still be trusted as a weight loss tool assuming you allow for the margin of error.

Performance score: 3.5/5

RunStar 4E Body Scale: Scorecard

RunStar 4E Body Scale: Should I buy?

Buy it if...

You’re looking for a decent affordable smart scale

A surprisingly solid set of features for such a cheap scale.

You only care about working towards a healthier BMI

As well as weight, the RunStar 4E delivers accurate BMI calculations.

Don't buy it if...

You want to be able to sync results with health apps

The RunStar isn’t capable of linking in with any sort of wider ecosystem.

Also consider

RunStar 8E SmartScan Pro

A superior, and pricier, smart scale capable of measuring more metrics and breaking them down into specific parts of the body.

How I tested

My family (two adults and three children) has been using the RunStar 4E for three months. We’ve used it to measure and track all types of metrics, including weight, BMI, and muscle mass. I carried out comparison tests with the more premium RunStar 8E SmartScan Pro. In addition, I’ve used every feature of the app to give the smart scales a thorough testing.

First reviewed: July 2026

Writer, app-hoarder, and professional "low battery" enthusiast. Paul spends his days testing wearables so you don’t have to, and his nights wondering if his sleep tracker is judging him. He’s fascinated by the tech that claims to make us better humans—and if it’s wearable, downloadable, or requires a firmware update, he has thoughts on it.

With over 20 years of experience and a first-class Computer Science degree, Paul has navigated the front lines of the tech and creative industries. His work has been published internationally and appears regularly in Digital Camera World and Creative Bloq.