Frequently Asked Questions

The questions we get asked most often. If yours is not here, email us.

Are BodyCompCheck tools accurate? +

Our tools use established formulas (Jackson-Pollock, Navy method, etc.) with known accuracy ranges. We clearly display the margin of error for each method. They are estimates, not medical measurements. For the most accurate results, use a DEXA scan or consult a professional.

Is my data stored on your servers? +

No. All calculations run in your browser. Your data is stored locally on your device using browser localStorage. We never see your numbers. You can clear your data at any time through your browser settings.

What is the most accurate body composition method? +

DEXA (Dual-Energy X-ray Absorptiometry) is considered the gold standard with an accuracy of plus or minus 1-2%. It also provides bone density and visceral fat data. However, it is more expensive and less accessible than other methods. Bod Pod and hydrostatic weighing are also highly accurate alternatives.

Can I use these tools instead of seeing a doctor? +

No. Our tools are for educational purposes only. They do not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for health decisions. See our Disclaimer for full details.

Why does my body fat percentage change so much day to day? +

Body composition methods are sensitive to hydration, food intake, exercise timing, and measurement conditions. BIA scales can vary 3-5% day-to-day. For consistency, measure at the same time of day under the same conditions—ideally first thing in the morning after using the bathroom.

How do I track progress if the scale is not reliable? +

Use multiple metrics: body fat percentage trends, circumference measurements, progress photos, strength benchmarks, and how your clothes fit. Our Lean Body Mass Calculator and Skinfold Tracker help you track lean mass changes over time.

What is normal weight obesity? +

Normal weight obesity is when someone has a BMI in the normal range (under 25) but an elevated body fat percentage (over 30% for women, over 25% for men). It carries metabolic health risks that BMI alone misses. Learn more in our article on normal weight obesity.

Do you offer personalized coaching or meal plans? +

No. We do not offer professional services, personalized coaching, or medical consultation. Our tools and articles are educational resources. For personalized advice, consult a registered dietitian, certified trainer, or physician.

Can I lose fat and gain muscle at the same time? +

Yes — body recomposition is possible, especially for beginners, people returning after a break, or those with higher body fat percentages. It becomes harder as you get leaner and more trained. Our Body Recomposition Planner can help you set realistic expectations.

How often should I measure my body composition? +

For most methods, every 2-4 weeks is ideal. Daily measurements create noise — hydration, food, and exercise timing cause day-to-day swings that hide real trends. BIA scales can vary 3-5% day-to-day. Skinfolds and DEXA are more stable but still benefit from consistent timing. Track monthly trends, not daily fluctuations.