BodyCompCheck

Stop Guessing. Start Measuring What Matters.

BMI tells you weight. We tell you composition. Free calculators, expert guides, and the truth about your body fat numbers.

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The Accuracy Hierarchy

Every method has error. Know how much before you trust the number.

DEXA Scan

±1-2% error

Gold standard. Gives bone density, visceral fat, and regional breakdown.

Bod Pod

±2-3% error

Air displacement. No radiation. Fast and comfortable.

Skinfold Calipers

±3-5% error

Portable and affordable. Requires skill and consistency.

Consumer BIA Scale

±5-8% error

Convenient but hydration-dependent. Good for trends, not absolutes.

Navy Method

±4-8% error

Free and fast. Just a tape measure. Limited for athletes.

BMI

±10-15% error

The old shortcut. Can't see muscle. Often misclassifies active people.

Free Body Composition Tools

All calculations run in your browser. Your data never leaves your device.

📏 Body Fat Percentage Estimator

Navy method, YMCA method, 3-site/7-site skinfold with Jackson-Pollock equations.

⚖️ BMI vs Body Fat Analyzer

Side-by-side health risk interpretation. Detects BMI false positives for athletes.

💪 Lean Body Mass Calculator

Calculate lean mass from weight and BF%. Includes bone mass and organ mass references.

📝 Skinfold Measurement Tracker

Site selection guide, measurement log with mm trend chart, technician error warnings.

⚡ Bioelectrical Impedance Guide

Hydration impact, electrode placement, consumer vs professional device accuracy.

📊 Body Recomposition Planner

Bulk/cut rates, maintenance calories, protein targets, timeline to goal BF%.

Multi-Frequency BIA Explained: Why Some Scales Cost $50 and Others Cost $5,000

I was at a fitness trade show in Seattle last month when a sales rep tried to sell me a multi-frequency BIA scale for forty-two hundred dollars.

August 19, 2026 ⏱ 5min read 🏷

The Body Fat Testing Protocol Every CrossFit Athlete Should Know Before Competition

David showed up at our Portland studio three days before the Rose City Summer Slam with a problem I had seen a dozen times before. He needed to make w...

August 18, 2026 ⏱ 5min read 🏷

Portland's Free Fitness Parks Are Changing How Locals Track Body Composition

I was jogging through Laurelhurst Park last Saturday morning when I noticed something new: a pop-up tent with a banner reading

August 17, 2026 ⏱ 5min read 🏷

GLP-1 Medications and Body Composition: What the Scale Won't Show You

Dr. Sarah Chen, an endocrinologist I collaborate with here in Portland, sent me a DEXA report last week that made me put down my coffee. Her patient —...

August 15, 2026 ⏱ 5min read 🏷

3D Body Scanner vs. DEXA: Which One Actually Tells the Truth in 2026?

A new wellness center opened on NW 23rd last month with a Styku 3D body scanner in the lobby and a DEXA machine in the back room. They are offering bo...

August 14, 2026 ⏱ 5min read 🏷

Can Your Smartphone Really Measure Body Fat? The 2026 AI PhotoScan Reality Check

My partner Alex sent me a link last month with the subject line

August 12, 2026 ⏱ 5min read 🏷

Common Questions

Is my data stored on your servers?

No. All calculations run in your browser. Your data is stored locally using localStorage.

Which method is most accurate?

DEXA is the gold standard with ±1-2% error. It also gives bone density and visceral fat data.

Can I use these tools instead of seeing a doctor?

No. Our tools are for educational purposes only. Always consult a qualified healthcare provider.

Why does my body fat change day to day?

Hydration, food intake, and exercise timing affect readings. BIA scales can swing 3-5% day-to-day.

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