Heart Rate Calculator
Calculate your heart rate training zones (fat burn, cardio, peak) using the Karvonen formula. Free heart rate calculator with zone chart.
Heart Rate at a glance
This page computes the measurement directly: instead of quoting a population average, the Heart Rate asks for your measurements and computes the index for your own body.
You can audit the arithmetic directly: open the page source and you will find the same equation constants from the lead paragraph and the rounding step - all in a few lines of plain JavaScript.
Calculate your heart rate training zones (fat burn, cardio, peak) using the Karvonen formula. Free heart rate calculator with zone chart.
About the Heart Rate Calculator
This calculator provides evidence-based targets and interpretation based on current nutritional science and dietary guidelines. The formulas and reference ranges used are drawn from authoritative sources including the National Academies of Sciences, Engineering, and Medicine (Dietary Reference Intakes), the USDA Dietary Guidelines for Americans 2025-2030, and peer-reviewed research published in journals such as the American Journal of Clinical Nutrition, the New England Journal of Medicine, and JAMA.
How this calculator works
The calculator uses validated formulas that account for individual factors such as age, sex, body weight, and activity level. The results are personalized to your inputs and include interpretation categories (low, normal, high) based on established clinical or nutritional reference ranges. Always interpret results in the context of your overall health, diet, and lifestyle, a single number rarely tells the full story.
Practical guidance
Use this calculator as a starting point for understanding your nutritional needs or health metrics. The results are educational, not diagnostic, always discuss significant findings with your healthcare provider before making changes to your diet, supplement regimen, or medication. For best results, recalculate periodically as your body composition, activity level, or health status changes. Track trends over time rather than focusing on single measurements, as day-to-day variation is normal and expected.
Evidence base and limitations
All nutritional targets are based on population-level recommendations that apply to most healthy individuals. Individual needs may vary based on genetics, medical conditions, medications, pregnancy, lactation, and other factors. The calculators do not replace professional medical or nutritional advice. If you have a chronic health condition, are pregnant or breastfeeding, or take medications that affect nutrient metabolism, consult a registered dietitian or physician for personalized guidance.
Formula sources, population limits, and references for this fitness calculator are documented in our public methodology. Read the methodology · Medical disclaimer