Health metrics, simplified for longevity.
Free calculators and clear guides covering BMI, calories, hydration, sleep, and fitness — designed for US and UK readers, with no signup and no data tracking.
How it works
One number is never the whole story.
Every HealthGood calculator pairs the result with a plain-English explanation, the formula we used, and a frank note on where it falls short. We want you to understand the number — not just see one.
Try the BMI calculator on the left, then explore related body-metric tools or read our deep-dive guides.
See all calculatorsHealth toolkits
Specialised calculators for every wellness goal.
Body Metrics
BMI, body fat, ideal weight, and shape ratios.
5 tools
Calories & Nutrition
Calories, protein, macros and metabolic rate.
5 tools
Hydration
Daily water intake based on weight and activity.
1 tool
Sleep
Sleep cycle, bedtime, and recovery tools.
2 tools
Fitness Metrics
Heart rate zones and activity calorie burn.
1 tool
Most-used calculators
Quick access to the tools readers come back to.
BMI Calculator
Estimate your Body Mass Index — a quick screening tool for whether your weight is in a healthy range for your height.
Calorie Calculator
Work out how many calories you need each day to maintain, lose, or gain weight using the Mifflin-St Jeor equation.
TDEE Calculator
Estimate the total calories your body burns each day from resting metabolism plus daily activity.
Water Intake Calculator
Estimate how much water to drink each day based on your body weight and activity level.
Sleep Calculator
Find the best times to fall asleep or wake up by aligning with 90-minute sleep cycles.
Macro Calculator
Split your daily calorie target across protein, carbohydrates, and fat using sensible ratios.
Latest evidence-based guides
Plain-English explanations of the metrics that matter.
body · metrics · 7 min read
What Is BMI and How Is It Calculated?
Body Mass Index is the most widely used screening tool for adult weight status. Here's exactly what it measures and what it doesn't.
body · metrics · 6 min read
BMI vs Body Fat Percentage: What's the Difference?
BMI and body fat percentage often disagree. Here's why, and which one to trust in different situations.
calories · nutrition · 8 min read
What Is TDEE? Total Daily Energy Expenditure Explained
TDEE is the total number of calories your body burns each day. Here's how it breaks down and how to use it.
calories · nutrition · 6 min read
What Is BMR? Basal Metabolic Rate Explained
BMR is the calories your body burns at complete rest. Here's how it's measured and why it matters.
calories · nutrition · 9 min read
How Many Calories Should I Eat to Lose Weight?
A practical, evidence-based guide to setting a calorie target for sustainable weight loss.
calories · nutrition · 7 min read
How to Create a Safe Calorie Deficit
Practical guidelines for losing weight without losing muscle, sleep, or your sanity.
"Finally a BMI calculator that explains what the number actually means."
"Clean, fast, and the macro guide is the clearest I've read."
"I appreciate the honesty about limitations. Refreshing."
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