The Nutrition Target Calculator is a practical diet-planning tool that estimates your daily calorie needs and converts them into personalized protein, carbohydrate, and fat targets. Whether your goal is fat loss, weight maintenance, or lean muscle gain, this calculator starts with the Mifflin-St Jeor equation to estimate resting energy expenditure, then applies your activity level and a safe weekly rate of change.
After calculating your daily calorie target, the tool breaks it into grams of protein, carbs, and fat using the macro split you select. You can choose a balanced split, a higher-protein split, or a lower-carbohydrate split to match your training style and food preferences. The full calculation breakdown shows each step, so you always know where your numbers come from.
This tool is designed for anyone planning meals, tracking calories, or setting nutrition goals — from first-time dieters to experienced lifters and busy coaches. Treat the result as an educated starting point, not a medical prescription.
👤 Your Details
⚙️ Activity & Goal
Step-by-Step Guide
Start by entering your sex, age, height, and weight in the Your Details section. Height can be entered in centimeters or inches, and weight in kilograms or pounds; the calculator converts everything to metric units before running the formulas. Next, select your activity level from the dropdown menu. This factor adjusts your basal metabolic rate (BMR) to account for the energy you burn through daily movement and structured exercise, so it is worth choosing honestly — an office worker who trains twice a week is usually closer to Light than to Moderate.
Then set your goal and your weekly rate of change. A rate of –0.5 kg/week creates a moderate calorie deficit suited to fat loss, while +0.25 kg/week supports a slow, lean muscle gain with minimal fat accumulation. Choose 0 to hold your weight steady. Finally, pick a macro split that fits your training style and food preferences, press Calculate Targets, and review the breakdown.
How It Works
The calorie target is built in three steps. First, the Mifflin-St Jeor equation estimates your BMR — the energy your body consumes at complete rest. For men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5. For women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161.
Second, your BMR is multiplied by an activity factor between 1.2 and 1.9 to estimate your Total Daily Energy Expenditure (TDEE). Third, the calculator applies your weekly rate of change. Because roughly 7700 kcal equals about 1 kg of body fat, the tool converts your selected pace into a daily calorie adjustment: losing 0.5 kg/week means a deficit of about 550 kcal per day, and gaining 0.5 kg/week means the same surplus. Macro grams are then derived from your selected split using the standard energy densities: protein and carbohydrates provide 4 kcal per gram, while fat provides 9 kcal per gram. The equation is well documented; you can read more about the Mifflin-St Jeor equation on Wikipedia.
Worked Example
Example: A 30-year-old woman, 165 cm tall, weighing 60 kg, moderately active (factor 1.55), wants to lose about 0.25 kg per week with a balanced split.
BMR = 10 × 60 + 6.25 × 165 − 5 × 30 − 161 = 1320 kcal/day.
TDEE = 1320 × 1.55 ≈ 2046 kcal/day.
Deficit = 0.25 × 7700 ÷ 7 ≈ 275 kcal/day.
Calorie target ≈ 1771 kcal/day.
Using the 30/40/30 split, the macro targets would be approximately: protein 133 g, carbs 177 g, and fat 59 g. If the same person instead chose to gain 0.25 kg/week, the calculator would add about 275 kcal per day instead of subtracting it.
Reference: Macro Split Options
Each split changes how your daily calories are distributed. The table below summarizes what each option emphasizes and who typically benefits most from it.
| Split | Protein | Carbs | Fat | Best for |
|---|---|---|---|---|
| Balanced 30/40/30 | 30% | 40% | 30% | General health, moderate training, most people |
| Higher Protein 35/35/30 | 35% | 35% | 30% | Strength training, appetite control, higher protein needs |
| Lower Carb 30/25/45 | 30% | 25% | 45% | Low-carb preference, fat adaptation, insulin sensitivity focus |
Common Mistakes to Avoid
One common error is mixing up units — typing your weight as if it were kilograms when you actually weigh it in pounds, or reading a result in pounds and assuming it is kilograms. Double-check the unit dropdowns before calculating. A second mistake is choosing an aggressive deficit. Even a moderately larger deficit than 0.5 kg/week can reduce energy, disrupt sleep, and increase muscle loss, so the tool deliberately keeps rates within a sustainable range.
Another mistake is treating protein as a percentage rather than a gram target. During weight loss, eating protein in grams based on body weight — often 1.6 to 2.2 g per kg — matters more than hitting a perfect percentage, because protein helps preserve lean mass. Finally, do not treat the output as a fixed prescription. Calories and hormones fluctuate day to day; the target is a starting point to test over 2–3 weeks and adjust based on real-world results.
Frequently Asked Questions
Should I recalculate after I lose weight? Yes. As your weight drops, your BMR decreases because smaller bodies burn fewer calories. Recalculate every 5 kg of weight change, or every 4–6 weeks, to keep your targets accurate.
What is the difference between BMR and TDEE? BMR is the energy your body needs at complete rest to keep organs functioning. TDEE adds the energy used for daily movement, digestion, and exercise. Your eating target is based on TDEE, not BMR.
Is this calorie target safe? The built-in rates of change limit you to a sensible deficit or surplus, but individual needs vary with medical conditions, medications, and body composition. If you have a health condition, are pregnant or nursing, or have a history of an eating disorder, consult a doctor or registered dietitian before changing your diet.
Additional Resources
For more detailed and evidence-based guidance on weight management, the U.S. National Institute of Diabetes and Digestive and Kidney Diseases provides a helpful weight management resource hub. You can also explore the Compendium of Physical Activities to refine how you estimate your activity level.