Calories Burned Walking, Running and Cycling
Real per-hour figures for the three most common forms of cardio, the MET arithmetic behind them, and how far off the number on your watch usually is.
Read the guide →Guides
The formulas behind the calculators, written out in plain English. What each number means, which study it came from, and the situations where it gives the wrong answer.
Body Fat Percentage Chart for Men and Women by Age
The standard charts, what the numbers mean for men and women at different ages, and the difference between what is average and what is healthy.
Read the guide →
BMI by Age: How the Number Shifts Over a Lifetime
The BMI thresholds are the same at 25 and at 75, but the body they are describing is not. What changes with age, and why a slightly higher BMI after 65 is associated with better outcomes.
Read the guide →What Counts as a Healthy Waist Size
Fixed waist thresholds ignore height, which is why waist-to-height ratio has largely replaced them. Half your height is the line worth using.
Read the guide →How to Reduce Your Waist Measurement by Two Inches
Waist circumference responds to energy balance, not to ab training. Two inches is roughly seven to nine pounds of fat, which is about two months at a moderate deficit.
Read the guide →The Air Force PT Test: Why the Waist Measurement Sits Inside the Score
The Air Force folded body composition into the fitness test instead of running it as a separate gate. A waist measurement contributes points alongside cardio and strength.
Read the guide →The Marine Corps PFT and CFT: What Each Test Is For
The Corps runs two tests. The PFT measures general fitness, the CFT measures combat tasks, and a high enough score on either can exempt a Marine from the body fat assessment.
Read the guide →The Navy PRT: How the Test Is Built and What Comes Before It
The Navy runs a body composition assessment before the physical readiness test. Here is the structure of both, the cardio options, and where the standards are published.
Read the guide →The Army Fitness Test: All Five Events and What Each One Measures
The AFT replaced the ACFT on 1 June 2025 and dropped the power throw. Five events, two standards, and a 60-point floor that fails the whole test on its own.
Read the guide →Military Body Composition Standards: How Each Branch Measures
The Army moved to waist-to-height in 2026. The Navy, Marine Corps and Air Force still use their own methods. A branch-by-branch read on what is measured and what is not.
Read the guide →