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%.

Skinny Fat Body Composition Myth 2026

I weigh 125 pounds. I am 5'6". My BMI is 20.2. Perfectly normal. My doctor never mentions my weight. My family calls me "skinny." And yet my body fat ...

July 23, 2026 ⏱ 5min read 🏷

The Dexa Scan That Changed How I See My Body

The DEXA Scan That Changed How I See My Body I stepped onto the DEXA platform at the fitness studio on NW 23rd wearing nothing but a sports bra and co...

July 16, 2026 ⏱ 5min read 🏷

Portland Heat Body Composition Scale Lies

My Body Composition Changed 8% in One Month—And It Had Nothing to Do with My Gym Routine Emily Clarke I stepped on my bioimpedance scale on August 1st...

July 06, 2026 ⏱ 5min read 🏷

Smart Scale Gained Muscle Jeans Said Otherwise

The scale congratulated me. It flashed a green arrow and a cheerful message: "Muscle mass increased by 8.2 lbs!" I stood there in my bathroom, naked a...

July 06, 2026 ⏱ 5min read 🏷

The 2026 No-Scale Challenge: Why Portland's Fitness Community Ditched the Scale - BodyCompCheck

The 2026 No-Scale Challenge: Why Portland's Fitness Community Ditched the Scale — BodyCompCheck

June 25, 2026 ⏱ 5min read 🏷

Why Does My Doctor Keep Using Bmi

Why Does My Doctor Keep Using BMI When I Can See My Abs? Have you ever walked out of a doctor's appointment feeling more confused than when you walked...

June 24, 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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