The Energy Nutrition Calculator estimates your daily calorie needs using the Mifflin-St Jeor equation, one of the most widely used and clinically validated methods for resting metabolic rate. It then applies an activity factor to find your total daily energy expenditure (TDEE) and adjusts for your goal — whether you want to lose fat, hold steady, or build lean mass.
Beyond calories, the tool converts your target into a practical macronutrient breakdown: grams of protein, carbohydrates, and fat per day, based on the macro plan you choose. Because individual needs vary, the calculator is an excellent starting point for meal planning, sports nutrition, and general healthy eating.
Use it as a quick baseline or a teaching tool for understanding energy balance. Whether you are planning meals, budgeting calories, or building a training diet, the numbers give you a clear starting point. All you need is your sex, age, height, weight, and typical activity level.
👤 Your Profile
Activity & Goal
📊 Suggested Daily Macros
Calculation Breakdown
How Your Energy Numbers Are Calculated
This calculator uses the Mifflin-St Jeor equation, which estimates resting metabolic rate (BMR) from body weight, height, age, and sex:
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
BMR is the energy your body needs at complete rest — breathing, circulation, cell repair, and brain activity — and typically accounts for 60–70% of daily energy use. The calculator multiplies BMR by an activity factor to estimate total daily energy expenditure (TDEE), then adds or subtracts calories for your goal: roughly −500 kcal/day for fat loss, no change for maintenance, or +300 kcal/day for muscle gain.
Step-by-Step Guide
Getting useful numbers takes about 30 seconds.
- Select your biological sex — the equation uses different constants for men and women.
- Enter your age in years; resting metabolism tends to decline with age.
- Enter your height in centimeters or feet, and your weight in kilograms or pounds.
- Choose the activity level that best matches an average week. Be honest — overestimating activity inflates the calorie target.
- Pick your goal and a macro plan, then press Calculate Energy Needs.
The results show BMR, TDEE, target calories, and a gram-based macro recommendation for your chosen plan.
📊 Macro Plan Reference
Macro plans express each nutrient as a percentage of total calories:
| Plan | Carbohydrates | Protein | Fat |
|---|---|---|---|
| Balanced | 40% | 30% | 30% |
| Lower Carb | 30% | 35% | 35% |
| Higher Carb | 55% | 20% | 25% |
| Keto | 5% | 25% | 70% |
Protein and carbs provide roughly 4 kcal per gram; fat provides 9 kcal per gram. That is why the calculator converts calories to grams differently for fat. Treat gram targets as a framework, not a daily exam.
⚡ Practical Tips
Use your calorie target as a weekly benchmark, not a rigid daily verdict. If your goal is 2,000 kcal/day, a 1,850 kcal Monday and a 2,150 kcal Tuesday can still average out by Friday. This flexibility makes consistency easier.
For body composition, protein matters. If you are cutting, choose a moderate or higher-protein plan and keep the deficit modest — 300–500 kcal/day is usually safer than a huge drop. If you are gaining, small surpluses (around +300 kcal) tend to favour muscle over excess fat.
Recalculate after a 4–5 kg weight change, because a lighter body burns fewer calories. Pair the tool with portion-level food calculators, like our oatmeal per-serving calculator, to see how everyday meals fit your budget.
Factors That Affect Accuracy
Mifflin-St Jeor is a population estimate, not a laboratory measurement. It is usually within about 10% for healthy adults, but muscle mass, thyroid function, medications, pregnancy, and recent weight changes can shift true needs. The activity multipliers are broad; someone with a physical job needs more than a desk worker doing three workouts a week, even if both are “active.”
If you need precise guidance for medical, pregnancy, or competitive weight-class situations, consult a registered dietitian or doctor rather than relying on an online estimate.
Frequently Asked Questions
Why is BMR different from TDEE? BMR is energy burned at rest. TDEE adds movement, exercise, digestion, and everyday activity, so it is typically 20–50% higher than BMR.
How long should I wait before adjusting? Give any target 2–3 weeks. If your weekly average weight moves 0.25–0.5 kg in the desired direction, the plan is working. Otherwise adjust by 100–200 kcal/day.
Are the macro percentages suitable for everyone? Not necessarily. Athletes often eat more carbs around training; some people feel better with higher protein or lower carbs. Use the plans as a starting point and adjust based on energy, performance, and preferences.