Health

Precise BMR Calculator (1970) for Weight Management

Calories burned at rest.

Height (cm)

Weight (kg)

Age

Sex

1,649kcal/day

Average

Metabolic recommendation

Solid baseline — focus on TDEE for goals

•Multiply BMR × activity factor (1.375–1.55) to get your TDEE.
•For weight loss, eat 300–500 kcal below TDEE — not below BMR.
•Spread protein (25–35 g) across 3–4 daily meals.
•Re-measure every 4–6 weeks as body weight changes.

Disclaimer: this tool is for informational purposes only and is not medical advice. Consult a qualified healthcare professional before making health decisions.

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Quick summary

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain vital functions.

How to calculate bmr manually

Record sex, age, weight (kg), and height (cm).
Apply the Mifflin-St Jeor equation.
Men: BMR = 10·weight + 6.25·height − 5·age + 5.
Women: BMR = 10·weight + 6.25·height − 5·age − 161.

Estimate basal metabolic rate using the Mifflin-St Jeor equation.

How it works

BMR = 10·weight + 6.25·height − 5·age + 5 (men) or − 161 (women).

Example

30y male, 175 cm, 70 kg → BMR ≈ 1,649 kcal/day.

Expert guide

Basal Metabolic Rate: the foundation of every weight plan

Your BMR is the number of calories your body burns at complete rest, just to keep your heart beating, lungs breathing, and brain firing. Knowing it accurately is the single most useful starting point for any U.S. weight management or fitness plan.

Why Mifflin-St Jeor is the modern gold standard

Several BMR equations exist (Harris-Benedict, Katch-McArdle, Mifflin-St Jeor), but the Academy of Nutrition and Dietetics formally endorses Mifflin-St Jeor as the most accurate predictive equation for healthy U.S. adults. It typically lands within 10% of indirect calorimetry, the lab gold standard. We use Mifflin-St Jeor here because it consistently outperforms the older 1919 Harris-Benedict formula — particularly for adults with above-average or below-average body composition.

What drives your BMR up or down

Roughly 60–75% of your daily calorie burn is BMR — far more than exercise. The biggest driver is lean body mass: a pound of muscle burns about 6 kcal/day at rest, vs roughly 2 kcal/day for fat. That's why strength training has such durable metabolic benefits. Age also matters: BMR drops about 1–2% per decade after age 20, mostly because of muscle loss. Crash dieting can suppress BMR by 10–20% as the body downshifts in response to chronic underfeeding (a phenomenon called metabolic adaptation).

From BMR to a real daily target (TDEE)

BMR is a baseline, not a target. To get your Total Daily Energy Expenditure (TDEE), multiply BMR by an activity factor: 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 active, 1.9 very active. Your TDEE is your maintenance calorie target. Subtract 500 kcal/day for steady weight loss (~1 lb/week), or add 250–500 kcal/day for lean muscle gain. Adjust every 4–6 weeks based on real scale and tape-measure trends.

Frequently asked questions

How does BMR affect weight loss?

BMR sets the floor for how many calories you burn each day. To lose weight you must eat below your TDEE (BMR × activity). A typical 500 kcal/day deficit produces about 1 lb/week of fat loss. Knowing your BMR prevents the common mistake of cutting calories too aggressively, which slows metabolism and triggers muscle loss.

Why is my BMR lower than someone the same weight as me?

Two people at the same weight can have very different BMRs because muscle burns more calories at rest than fat. Sex, age, height, hormonal status, and even genetics also play a role. Strength training and protein intake are the most reliable ways to nudge your BMR upward over time.

Should I eat at my BMR to lose weight?

No. Eating at BMR (with no activity adjustment) is too aggressive a deficit for most adults and can stall metabolism. Eat at your TDEE minus 300–500 kcal/day. The U.S. Dietary Guidelines recommend never dropping below 1,500 kcal/day for men or 1,200 kcal/day for women without medical supervision.

Fact-checked by Calcly Editorial Team

Editorial disclaimer

For informational purposes only. Consult a certified medical professional before making health decisions.

How we calculate your BMR (Mifflin-St Jeor)

BMR = 10·weight(kg) + 6.25·height(cm) − 5·age + s   (s = +5 men, −161 women)

We use the Mifflin-St Jeor equation, considered the most accurate predictive BMR formula for healthy U.S. adults by the Academy of Nutrition and Dietetics. It estimates the energy your body needs at complete rest to maintain vital functions. Multiply BMR by an activity factor (1.2 sedentary → 1.9 very active) to get your TDEE.