Body composition
Visceral fat rating vs visceral fat area: what each number means
A scale's visceral fat rating has no unit; visceral fat area is in cm². Learn where each number comes from and how to compare readings without mixing scales.
Body composition methodsBy Lena Hartwell · 11 min read ·
Are smart scales accurate for body fat?
Learn what a smart scale measures, why body-fat estimates differ, and how to check a change with a worked example.
Body composition methodsBy Lena Hartwell · 10 min read ·
What is ABSI? How to read A Body Shape Index result
Learn how ABSI uses waist, height, and weight. Follow a worked example and read the age and sex reference score without treating it as a diagnosis.
Body measurement methodsBy Lena Hartwell · 9 min read ·
What does an ideal body weight calculator actually mean?
Compare four ideal body weight formulas with a worked example. See why their results differ and why no single number is a personal target.
Body compositionBy Lena Hartwell · 10 min read ·
What is body roundness index? How to read a BRI result
See how body roundness index uses waist and height, check a worked example, and learn what the result can and cannot show.
Body compositionBy Lena Hartwell · 10 min read ·
BMI vs body fat percentage: what is the difference?
Compare a weight-to-height screening measure with an estimate of the share of body weight that is fat.
Body compositionBy Lena Hartwell · 7 min read ·
The Difference Between Fat Mass and Body Fat Percentage
Fat mass is a weight; body fat percentage is a share of body weight. See worked examples, fat mass index, and why the method stays part of the result.
Body compositionBy Lena Hartwell · 17 min read ·
Waist-to-Height Ratio vs BMI: What Each Number Shows
Compare the inputs, uses, and limits of two common screening numbers.
Body compositionBy Lena Hartwell · 8 min read ·
What FFMI measures and what it cannot tell you
See how fat-free mass index uses an estimated body-fat input and height, and why it is different from muscle mass or a personal limit.
Body compositionBy Lena Hartwell · 13 min read ·
How muscle mass is estimated
See what a waist-based muscle estimate uses and why it is different from lean mass.
Body compositionBy Lena Hartwell · 8 min read ·Measurement
How to convert pounds, feet, and inches for body calculators
Convert height, weight, and tape readings with the right units. Follow a worked example and avoid rounding or mixing measurement sites.
Measurement arithmeticBy Lena Hartwell · 9 min read ·
How to calculate BMI: examples with solutions in kg and pounds
BMI calculation examples with solutions: metres, centimetres and pounds-and-inches sums worked step by step, a result on a category line, and the right age reference.
Measurement arithmeticBy Lena Hartwell · 14 min read ·
How to calculate waist-to-hip ratio
Divide a waist measurement by a hip measurement with matching units, then record the method and rounding.
Measurement arithmeticBy Lena Hartwell · 9 min read ·
Waist circumference vs waist-to-height ratio
Compare a waist measurement in centimetres or inches with the same measurement divided by height.
MeasurementBy Lena Hartwell · 14 min read ·
How to take tape measurements
Use the right landmarks for your selected method.
MeasurementBy Lena Hartwell · 7 min read ·Energy & nutrition
Caffeine half-life: how much caffeine is left at bedtime
Caffeine's half-life is about 5 hours on average but varies widely. Work out how much is left from each drink at bedtime, and what sleep studies found.
Nutrition arithmeticBy Lena Hartwell · 9 min read ·
Gross vs net exercise calories: include or subtract rest
Compare session calories with and without resting energy. Work through a gross-to-net example and keep time, units, and the resting baseline consistent.
Energy estimatesBy Lena Hartwell · 8 min read ·
How to convert macro percentages into grams
Convert a calorie amount and a stated carbohydrate, protein, and fat split into grams.
Food-energy arithmeticBy Lena Hartwell · 8 min read ·
Kilojoules to Calories (kJ to kcal): converter and table
Convert kJ to Calories or Calories to kJ with one factor, 4.184. Use the live converter or the table of common food-label values.
Food-energy arithmeticBy Lena Hartwell · 10 min read ·
Protein calculator results: what the reference value means
Understand what a grams-per-kilogram reference converts and what it cannot tell you.
Food-energy arithmeticBy Lena Hartwell · 9 min read ·
BMR vs RMR vs TDEE: The Difference and What Each Means
Compare resting and whole-day energy numbers without treating an estimate as a measurement.
Energy estimatesBy Lena Hartwell · 15 min read ·
How to choose an activity level
Include your whole day, not only your workouts.
Energy estimatesBy Lena Hartwell · 7 min read ·Fitness
VO₂ max units: convert L/min and mL/kg/min
Convert oxygen uptake between L/min and mL/kg/min with worked examples. Use the weight from the same test and keep estimates separate from measurements.
Fitness arithmeticBy Lena Hartwell · 7 min read ·
How to calculate a one-rep max estimate
Calculate a one-rep max estimate from a completed set, compare three equations, and understand what the result can and cannot tell you.
Strength estimatesBy Lena Hartwell · 10 min read ·
