Health & Fitness · Free tool
BMR Calculator
Estimate your basal metabolic rate with the Mifflin-St Jeor formula online for free. Calculate calories burned at rest instantly in your browser without signup.
BMR (at rest)
1,669 kcal/day
TDEE (with activity)
2,587 kcal/day
About these numbers
- BMR is calories burned at complete rest (Mifflin–St Jeor equation).
- TDEE is BMR multiplied by your activity factor.
- Use TDEE as a baseline for maintenance, cutting, or bulking.
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What it does
Calculate your Basal Metabolic Rate — the calories you burn at complete rest — using the Mifflin-St Jeor equation, the current standard used by dietitians. Enter age, sex, weight, and height, then pick an activity level to see your Total Daily Energy Expenditure (TDEE): the calories you need to maintain your current weight with normal activity.
Use BMR as a baseline and TDEE as the number to eat for maintenance; subtract 500/day for roughly a pound of loss per week, add 250/day for lean gains. Compare with calorie calculator for goal-based targets, or macro calculator to split TDEE into protein, carbs, and fat.
Embed this tool on your siteShow snippetHide
Paste this snippet into any page. Loads on-demand (lazy), no tracking scripts, and sized to most dashboards. Replace the height to fit your layout.
<iframe src="https://freetoolarena.com/embed/bmr-calculator" width="100%" height="720" frameborder="0" loading="lazy" title="BMR Calculator" style="border:1px solid #e2e8f0;border-radius:12px;max-width:720px;"></iframe>Example input & output
Input
32-year-old male, 180 lbs, 5'10", moderately activeOutput
BMR: 1,770 kcal/day
TDEE: 2,745 kcal/day (× 1.55 activity factor)Subtract 500/day (~2,245 kcal) for roughly 1 lb/week loss; add 250/day for slow lean gain.
How to use it
- Enter age, sex, weight, and height (metric or imperial).
- Pick the activity level that matches your week.
- Read your BMR (resting) and TDEE (daily need).
- Adjust intake relative to TDEE based on your goal.
When to use this tool
- Setting a daily calorie target for weight loss, maintenance, or lean gain.
- Understanding the floor of calories your body burns just staying alive.
- Estimating how many calories an activity level above sedentary adds to your needs.
- Pairing with a macro calculator to split calories into protein, carbs, and fat.
When not to use it
- Under 18 — adolescent metabolism differs; use a pediatric nutrition resource instead.
- Pregnant or breastfeeding — energy needs rise beyond what this equation models.
- Recovery from an eating disorder — any calorie math should come from your care team.
Frequently asked questions
- Is Mifflin-St Jeor more accurate than Harris-Benedict?
- Slightly, yes — Mifflin-St Jeor (1990) was calibrated on modern body compositions and tends to underestimate BMR by ~5% less than Harris-Benedict (1919). That's why dietitians default to it today.
- Why is my TDEE so much higher than my BMR?
- TDEE multiplies BMR by an activity factor (1.2–1.9). A desk worker with 4 workouts/week is ~1.55; a full-time laborer is ~1.7. Even at the same weight, a more active person needs 500+ extra kcal/day.
- Should I eat exactly my BMR to lose weight?
- No — never eat below your BMR for more than a short cut. Eating below BMR for weeks tanks adherence, mood, and lean mass. Drop from TDEE instead (a 300–500 kcal deficit is plenty).
- How often should I recalculate?
- Every 10 lbs of weight change or every 3 months, whichever comes first. BMR scales with body mass, so a 20-lb loss means your maintenance number is now a few hundred kcal lower.
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Learn more
Guides about this topic
- Using Our Tools · GuideHow to calculate TDEE and BMREstimate your BMR and TDEE using 5 activity multipliers in 2 minutes. Get a worked example for a 170-lb person instantly, free, and with no sign-up.
- How-To & Life · GuideHow to Calculate Your BMRCompare Mifflin-St Jeor and Harris-Benedict formulas to find your BMR. Understand metabolic adaptation instantly with this free, no sign-up online guide.
- How-To & Life · GuideHow to Sleep BetterCreate 10 sleep habits that improve rest quality without melatonin marketing. Free, instant online guide with no sign-up needed.
- How-To & Life · GuideHow to Drink More WaterUse habit stacks and bottle tricks to drink more water effortlessly. Free instant guide on recognizing your hydration signals in your browser.
- How-To & Life · GuideBeginner Workout Plan at HomeA 4-week home workout for complete beginners. Bodyweight only, 20-30 minutes, three days a week.
- How-To & Life · GuideHow to Start RunningStart running without hating it. Follow a walk‑run plan to your first 5K in 8 weeks, plus learn injury avoidance tips. Free online guide, no sign‑up required.
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