Plain-English health guides: practical examples, common mistakes, and the assumptions behind each calculator.
Health classes often teach a simplified version of reproductive biology, leading to confusion about fertility. By looking at the actual numbers behind cycle lengths and sperm survival, we can clear up 13 common misconceptions about how ovulation really works.
Aug 14, 2026 · 5 min read
Learn how to calculate your maximum heart rate using the classic 220-minus-age formula, the Tanaka method for men, the Gulati method for women, or a physical field test. Finding your peak heart rate helps you establish accurate training zones for better workouts.
Aug 13, 2026 · 5 min read
Learn how to calculate your lean body mass using clinical formulas and body fat percentages. These four practical examples show exactly how weight, height, and biological sex interact to determine your fat-free mass.
Aug 12, 2026 · 6 min read
Heart rate zones are not universal. Learn how your age, resting pulse, calculation methods, and daily environment shift your training zones, and why your numbers might look completely different from your workout partner.
Aug 11, 2026 · 6 min read
Learn how to accurately track your pregnancy timeline using your last menstrual period or ultrasound results. This guide breaks down the math behind your estimated due date, current trimester, and upcoming pregnancy milestones.
Aug 10, 2026 · 5 min read
Learn the most common errors people make when estimating their intoxication levels, from miscounting standard drinks to entering the wrong start time, and how to get a more accurate result.
Aug 9, 2026 · 6 min read
Learn how to calculate your Total Daily Energy Expenditure to figure out exactly how many calories you burn each day. This step-by-step guide explains how to use your BMR, activity level, and weight goals to find your ideal calorie and macro targets.
Jul 13, 2026 · 5 min read
A simple data entry error or misunderstanding of gestational math can throw off your estimated due date by weeks. Learn the most common errors people make when calculating their pregnancy timeline and how to get the right numbers.
Jul 12, 2026 · 5 min read
Learn the exact math behind setting up a proper macro split. By anchoring your protein to your body weight, setting a healthy baseline for fat, and filling the rest with carbs, you can optimize your diet for fat loss or muscle growth.
Jul 11, 2026 · 5 min read
Ideal body weight formulas were originally designed for hospital drug dosing, not fitness goals. Learn how these calculations work, why they ignore muscle mass, and how to use them as a helpful reference rather than a strict rule.
Jul 10, 2026 · 5 min read
Fitness trackers and apps use standard MET formulas to estimate energy expenditure, but individual factors like body composition, mechanical efficiency, and the environment can throw those numbers off by up to 20 percent. Here is how to actually use the data.
Jul 9, 2026 · 5 min read
The standard 2,000-calorie diet isn't right for everyone. Learn how to calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) to find the exact number of calories your body actually needs to maintain, lose, or gain weight.
Jul 8, 2026 · 5 min read
Learn the difference between total weight and body fat, why men and women have different healthy ranges, and how to accurately measure your body composition at home using just a flexible tape measure.
Jul 7, 2026 · 5 min read
Learn how to calculate your basal metabolic rate manually. We break down the math behind the Mifflin-St Jeor and Katch-McArdle formulas so you can understand exactly how your age, height, weight, and body composition drive your daily energy needs.
Jul 6, 2026 · 5 min read
Body mass index is a simple math equation, but it is often misunderstood. Learn the truth behind five common BMI myths and discover what this number actually tells you about your health, body fat, and weight categories.
Jun 23, 2026 · 5 min read