Why does my body fat percentage look different in the Styku app vs. the PDF report?

The difference between the body fat percentage shown in the Styku mobile app and the number on your PDF report is not a bug or an error. The two platforms use different scientific models to calculate body fat, which is why the numbers look different for the same scan.

Two Models, Two Numbers

Styku Mobile App — Advanced Model (Three-Compartment Model)

The mobile app calculates body fat using an Advanced Three-Compartment Model. This model separates your body into three distinct categories: fat mass, lean muscle mass, and bone mass. It is based on research derived from DEXA (Dual-Energy X-ray Absorptiometry) scanning, which is considered the gold standard in medical body composition analysis. Styku's body composition algorithm is scientifically validated and is generally within 1–2% of a DXA scanner. Because this model accounts for bone mass separately, it tends to report a higher body fat percentage than what traditional gym scales or basic measurement tools show.

PDF Report — Basic Model (Two-Compartment Model)

The PDF report your facility generates uses a Basic Two-Compartment Model. This model is designed to produce results that align more closely with traditional body composition tools like bioelectrical impedance analysis (BIA) devices (for example, InBody). It groups bone mass and lean muscle mass together into one "non-fat" category. Because bone is not separated out, this model typically reports a lower body fat percentage.

Note on BIA comparisons: BIA devices such as InBody rely on hydration levels to predict body composition, which can introduce a high degree of error between scans. Styku's 3D depth-sensing approach is not reliant on hydration levels, making it less error-prone and more reliable for tracking change over time. Additionally, BIA devices require strict pre-test protocols (fasting, avoiding exercise, controlling time of day, etc.), whereas Styku only requires form-fitting clothing.

Which Number Should You Use?

Both numbers are valid — they just measure differently. Here are a few things to keep in mind:

Consistency matters most. Whichever number you use to track progress, stick with the same model over time so your comparisons are meaningful.
The app's Advanced Model is more detailed. If you want the most rigorous estimate of body fat, the three-compartment model in the app is the better reference.
The PDF's Basic Model may feel familiar. If you're used to results from a BIA device or gym scale, the PDF number will be closer to what you've seen before.
Neither number alone tells the whole story. Look at trends across multiple scans rather than focusing on a single reading. Styku also provides 21 body circumferences, body surface area and volume segmentations, and health risk indicators such as waist circumference and waist-to-hip ratio to give a fuller picture of your body composition and health.

Summary

| Styku Mobile App | PDF Report

**Model** | Advanced (Three-Compartment) | Basic (Two-Compartment)

**Separates bone mass?** | Yes | No

**Typical result** | Higher BF% | Lower BF%

**Based on** | DEXA research | BIA scale methodology

If this resolves your issue, no further action is needed.

If the problem persists, contact support and include: the name of the facility where you were scanned, the date(s) of the scan(s) in question, the exact body fat percentage values shown in both the app and the PDF, and screenshots of each if possible.

Applies to: Styku mobile app (iOS and Android) and Styku Studio PDF reports — all Styku configurations

Related Resources

Body Composition Metrics — Body Fat, Lean Mass, Weight, and Sarcopenia
Body Composition Analysis: Methods, Models, and Measurement Levels
Styku vs. Inbody and other BIA devices