How big a deficit is safe?

A 500 kcal/day deficit ≈ 0.5 kg/week and is widely considered sustainable. Avoid extreme cuts.

What formula does the Calorie & BMR use?

It calculates using Mifflin-St Jeor: BMR = 10·kg + 6.25·cm − 5·age + s; TDEE = BMR × activity. The guide above walks through what each part means with a worked example.

How accurate is the Calorie & BMR?

It uses established, widely-accepted formulas and gives a reliable estimate for the values you enter. Everyone's body is different, so use the result as a helpful guide — not a medical diagnosis.

Is the Calorie & BMR a substitute for medical advice?

No. It's an educational estimate. For guidance tailored to you, always consult a qualified healthcare professional before making changes.

Is this calculator free to use?

Yes — every GKCalculators calculator is 100% free with no sign-up required. Create a free account only if you want to save your calculation history across devices.

All calculations run instantly in your browser. Nothing is sent anywhere unless you tap ‘Explain my results’ (AI) or ‘Save’ while signed in.

Can I share my result?

Yes. Tap Share and we copy a link with your exact inputs baked in, so anyone who opens it sees the same result.

Calorie & BMR

Basal metabolic rate (Mifflin-St Jeor) and daily calorie targets by goal.

Compare

Gender

Age

Height (cm)

Weight (kg)

Activity level

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Daily calories to maintain weight

2,587 kcal

BMR (at rest): 1,669 kcal

Mild weight loss (−0.25 kg/wk)

2,337 kcal

Weight loss (−0.5 kg/wk)

2,087 kcal

Weight gain (+0.25 kg/wk)

2,887 kcal

BMR

1,669 kcal

AI Breakdown & Smart Takeaway

Plain-English insight on your numbers

Get a personalized explanation of what these results mean — and how to improve them.

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How the Calorie & BMR works

This calculator uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR) and then applies your activity level to compute your Total Daily Energy Expenditure (TDEE), giving you precise calorie targets for weight loss, maintenance, or muscle gain. It's built for anyone who wants a science-backed starting point for a diet or fitness plan rather than guessing.

BMR is the energy you burn at complete rest. Multiplying by an activity factor gives TDEE — calories to maintain weight.

We then show targets for gentle or faster weight loss and for gaining.

Formula

Mifflin-St Jeor: BMR = 10·kg + 6.25·cm − 5·age + s;  TDEE = BMR × activity

Pro tips

Recalculate every few kilos — your TDEE changes as your weight does.

Key terms

BMR (Basal Metabolic Rate): — The number of calories your body requires at complete rest to sustain essential physiological functions like breathing, circulation, and temperature regulation.
TDEE (Total Daily Energy Expenditure): — Your total calorie burn over 24 hours, combining BMR with the energy cost of all physical activity and digestion.
Mifflin-St Jeor Equation: — A validated predictive formula developed in 1990 that estimates BMR from sex, age, height, and weight, and is considered the most accurate standard formula for most adults.
Activity Factor (PAL): — A multiplier applied to BMR that accounts for your daily physical activity level, ranging from sedentary (1.2) to very active or athletic (1.725–1.9).
Caloric Deficit: — The state of consuming fewer calories than your TDEE, which forces the body to draw on stored energy (primarily fat) to meet its needs.
Macros (Macronutrients): — The three primary nutrient categories — protein, carbohydrates, and fat — whose caloric ratios within your daily target determine body composition and performance outcomes.