Health / Browser tools
BMR Calculator
Compare resting calorie estimates from Mifflin-St Jeor, revised Harris-Benedict and, with body fat, Katch-McArdle.
BMR Calculator: Compare resting calorie estimates from Mifflin-St Jeor, revised Harris-Benedict and, with body fat, Katch-McArdle. Runs 100% locally in your browser with zero server file uploads.
- Category
- Health & sport tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Estimates for adults only. Not suitable for pregnancy, breastfeeding or a personalised treatment plan. Activity factors are broad assumptions; actual needs vary.
Resting energy equations
Mifflin et al., 1990: resting kcal/day = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5 for men, or −161 for women. https://pubmed.ncbi.nlm.nih.gov/2305711/
Revised Harris-Benedict (Roza and Shizgal): men use 88.362 + 13.397 × kg + 4.799 × cm − 5.677 × age; women use 447.593 + 9.247 × kg + 3.098 × cm − 4.330 × age. Formula table: https://pmc.ncbi.nlm.nih.gov/articles/PMC9246861/
Body composition and uncertainty
Katch-McArdle uses 370 + 21.6 × fat-free mass in kg, where fat-free mass is weight × (1 − body-fat percentage / 100). https://pmc.ncbi.nlm.nih.gov/articles/PMC12425712/
These are adult population estimates, not measured metabolism. They are not suitable for pregnancy, breastfeeding or setting a clinical nutrition plan.
How to use it
- Enter adult age, sex, weight in kilograms and height in centimetres.
- Add body fat if known to include Katch-McArdle.
- Compare the three resting estimates before allowing for activity.
Privacy & limitations
Your inputs stay in this browser. Nothing you enter is uploaded or saved.
Related tools
Frequently asked questions
Is BMR my daily calorie allowance?
No. Resting energy excludes most daily movement and exercise. Use the TDEE table to explore activity.
Why do the formulas disagree?
They were fitted to different samples and use different inputs. Body-fat measurement error also affects Katch-McArdle.
Free tool · runs in your browser · no account required