Calorie Calculator (TDEE & Macros)

Calculate your daily calorie needs and macronutrient targets. Get personalized protein, carbs, and fat goals for weight loss, maintenance, or muscle gain based on your TDEE.

Age

Weight (lbs)

Height (in)

Activity level

Your goal

Diet type

Body fat %

Providing your body fat percentage improves accuracy by using the Katch-McArdle formula.

Your daily calories

1,940 kcal/day

Maintain weight (0 lbs/week)

TDEE (maintenance): 1,940 kcal/day

BMR (at rest): 1,617 kcal/day

Formula: Mifflin-St Jeor (recommended)

Macronutrient breakdown

30%

40%

30%

Protein: 146g (30%)

Carbs: 194g (40%)

Fat: 65g (30%)

Protein intake: 2.1 g/kg body weight

Calorie targets by goal

Goal	Weekly change	Daily calories
Lose weight	-1.1 lbs/week	1,500
Maintain weight	0 lbs/week	1,940
Gain weight	+1.1 lbs/week	2,440

This calorie target is below the recommended safe minimum (1500 kcal/day). Consult a healthcare professional before following a very low calorie diet.

Macros by goal (Balanced)

Goal	Daily calories	Protein (g)	Carbs (g)	Fat (g)
Lose weight	1,500	113	150	50
Maintain weight	1,940	146	194	65
Gain weight	2,440	183	244	81

Want to compare BMR formulas and see your TDEE for all activity levels?

BMR Calculator

Know your body fat percentage for more accurate results?

Body Fat Calculator

BMR Calculator (Basal Metabolic Rate)Body Fat Calculator

Calorie calculator. Daily calories, TDEE, and macros for your goal.

A calorie calculator estimates how many calories you need per day based on your age, height, weight, and activity level using the Mifflin-St Jeor equation. It shows your TDEE for maintenance, a 500-calorie deficit for weight loss, and a 500-calorie surplus for muscle gain, with protein, carb, and fat grams for each goal.

What Is a Calorie Calculator and Why Do You Need One?

A calorie calculator is a tool that estimates your Total Daily Energy Expenditure (TDEE) — the total number of calories your body burns in a day, including exercise — and then adjusts that number for your specific goal: lose weight, maintain weight, or gain muscle. The calculation starts with your Basal Metabolic Rate (BMR), the energy your body needs at complete rest, and multiplies it by an activity factor that accounts for how much you move throughout the day.

Most people have no intuitive sense of how many calories they actually need. A sedentary 35-year-old woman who is 5'4" (163 cm) and weighs 140 lb (64 kg) needs roughly 1,750 calories per day to maintain her weight, while an active 25-year-old man who is 5'10" (178 cm) and weighs 175 lb (79 kg) needs approximately 2,850 calories. Without calculating, most people either undereat (stalling their metabolism) or overeat (gaining fat they don't want).

This calculator uses the Mifflin-St Jeor equation as the default BMR formula — the method recommended by the Academy of Nutrition and Dietetics and validated as the most accurate predictive equation in a 2005 systematic review by Frankenfield et al. If you know your body fat percentage, the calculator switches to the Katch-McArdle formula, which uses lean body mass instead of total weight and is more accurate for muscular or very lean individuals. Both formulas are then multiplied by your activity level to produce your TDEE, and the result is adjusted by ±500 calories for weight loss or gain goals.

How to Calculate Your Daily Calorie Needs (Step by Step)

To calculate how many calories you should eat per day, you need five pieces of information: your sex, age, height, weight, and activity level. Here is the step-by-step process this calculator follows:

1. Calculate your BMR using the Mifflin-St Jeor equation. For men: (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5. For women: (10 x weight in kg) + (6.25 x height in cm) - (5 x age) - 161.

2. Multiply your BMR by your activity multiplier to get your TDEE (maintenance calories). Sedentary (office job, no exercise): BMR x 1.2. Lightly active (light exercise 1-3 days/week): BMR x 1.375. Moderately active (moderate exercise 3-5 days/week): BMR x 1.55. Very active (hard exercise 6-7 days/week): BMR x 1.725. Extra active (athlete or very physical job): BMR x 1.9.

3. Adjust for your goal. To lose weight: subtract 500 calories from TDEE (produces roughly 1 lb/0.45 kg of fat loss per week). To maintain: eat at your TDEE. To gain muscle: add 500 calories to TDEE.

4. Split your calories into macronutrients. Select a diet preset — Balanced (30% protein, 40% carbs, 30% fat), Low Carb (40% protein, 20% carbs, 40% fat), High Protein (40% protein, 35% carbs, 25% fat), or Keto (20% protein, 5% carbs, 75% fat) — and the calculator converts percentages into grams using 4 calories per gram for protein and carbs, and 9 calories per gram for fat.

Alternative: if you know your body fat percentage (measure it with our body fat calculator), enter it to switch to the Katch-McArdle formula: BMR = 370 + 21.6 x lean body mass in kg. This formula ignores sex and age entirely and relies on your actual lean tissue, making it significantly more accurate for people who lift weights or have an above-average muscle mass.

Calorie Calculator Formulas: Mifflin-St Jeor and Katch-McArdle

TDEE = BMR \times ActivityMultiplier

$TDEE$ = Total Daily Energy Expenditure — your daily calorie need including exercise
$BMR$ = Basal Metabolic Rate — calories burned at complete rest
$W$ = Body weight in kilograms
$H$ = Height in centimeters
$A$ = Age in years
$LBM$ = Lean Body Mass in kilograms (weight minus fat mass)

Mifflin-St Jeor equation (default — used when body fat % is not provided):

BMR_{male} = 10W + 6.25H - 5A + 5

BMR_{female} = 10W + 6.25H - 5A - 161

Katch-McArdle equation (used when body fat % is provided):

BMR = 370 + 21.6 \times LBM

where lean body mass is calculated as:

LBM = W \times \left(1 - \frac{BF\%}{100}\right)

Activity multipliers convert BMR to TDEE:

Activity Level	Multiplier	Description
Sedentary	1.2	Desk job, no exercise
Lightly active	1.375	Light exercise 1-3 days/week
Moderately active	1.55	Moderate exercise 3-5 days/week
Very active	1.725	Hard exercise 6-7 days/week
Extra active	1.9	Athlete or very physical job

Macronutrient grams are calculated from the calorie target:

Protein\ (g) = \frac{Calories \times ProteinPct}{100 \times 4}

Carbs\ (g) = \frac{Calories \times CarbPct}{100 \times 4}

Fat\ (g) = \frac{Calories \times FatPct}{100 \times 9}

The Mifflin-St Jeor equation was published in 1990 and has been shown to predict resting metabolic rate within 10% of measured values in more individuals than Harris-Benedict, Owen, or WHO/FAO equations. The Katch-McArdle formula is preferred when body fat data is available because lean body mass is the strongest single predictor of metabolic rate — two people at the same weight but different body compositions will have very different calorie needs.

Calorie Calculation Examples for Real Scenarios

Example 1: 30-Year-Old Woman Wanting to Lose Weight

Sarah is 30 years old, 5'5" (165 cm), weighs 155 lb (70 kg), and exercises moderately 3-4 times per week.

Step 1 — BMR (Mifflin-St Jeor, female): (10 x 70) + (6.25 x 165) - (5 x 30) - 161 = 700 + 1,031.25 - 150 - 161 = 1,420 kcal.

Step 2 — TDEE: 1,420 x 1.55 (moderately active) = 2,201 kcal/day to maintain her weight.

Step 3 — Weight loss target: 2,201 - 500 = 1,701 kcal/day (produces approximately 1 lb of fat loss per week).

Step 4 — Macros (Balanced preset: 30/40/30): Protein = 1,701 x 0.30 / 4 = 128 g. Carbs = 1,701 x 0.40 / 4 = 170 g. Fat = 1,701 x 0.30 / 9 = 57 g.

Sarah's 1,701 kcal is comfortably above the 1,200 kcal safety minimum for women, so this deficit is sustainable. At 128 g of protein per day (1.83 g/kg), she has plenty to preserve muscle during her cut.

Example 2: 25-Year-Old Man Building Muscle

Jake is 25 years old, 5'11" (180 cm), weighs 165 lb (75 kg), body fat 15%, and trains hard 5-6 days per week.

Since body fat is provided, the calculator uses Katch-McArdle.

Step 1 — Lean body mass: 75 x (1 - 0.15) = 63.75 kg.

Step 2 — BMR (Katch-McArdle): 370 + (21.6 x 63.75) = 1,747 kcal.

Step 3 — TDEE: 1,747 x 1.725 (very active) = 3,014 kcal/day for maintenance.

Step 4 — Muscle gain target: 3,014 + 500 = 3,514 kcal/day.

Step 5 — Macros (High Protein preset: 40/35/25): Protein = 3,514 x 0.40 / 4 = 351 g. Carbs = 3,514 x 0.35 / 4 = 307 g. Fat = 3,514 x 0.25 / 9 = 98 g.

At 351 g protein (4.68 g/kg), this is unusually high — most research caps the benefit of protein at 2.2 g/kg (165 g for Jake). He could switch to the Balanced preset to get 263 g protein, which is still above the evidence-based threshold for muscle synthesis.

Example 3: Activity Level Impact — Same Person, Five Scenarios

How much does activity level change your calorie needs? Consider a 40-year-old man, 5'9" (175 cm), 176 lb (80 kg). His BMR is (10 x 80) + (6.25 x 175) - (5 x 40) + 5 = 1,699 kcal.

Activity Level	Multiplier	TDEE (kcal)	Weight Loss (kcal)	Gain (kcal)
Sedentary	1.2	2,039	1,539	2,539
Lightly active	1.375	2,336	1,836	2,836
Moderately active	1.55	2,633	2,133	3,133
Very active	1.725	2,931	2,431	3,431
Extra active	1.9	3,228	2,728	3,728

The difference between sedentary and extra active is 1,189 calories per day — nearly a full extra meal. This is why accurately classifying your activity level is the single most impactful choice in the calculator. When in doubt, pick one level lower than you think; most people overestimate their activity.

Tips for Using Your Calorie and Macro Results

Treat your TDEE as a starting point, not a final answer. The Mifflin-St Jeor equation predicts BMR within 10% of measured values for about 70-82% of people. That means your true maintenance could be 150-200 calories higher or lower than the number shown. Eat at your calculated target for 2-3 weeks, weigh yourself daily at the same time, and average the weekly weigh-ins. If your weight stays flat, you found your true maintenance. If you are losing or gaining, adjust by 100-200 calories.
Never go below the safety minimums: 1,200 calories per day for women and 1,500 for men. Below these thresholds, it becomes nearly impossible to get adequate vitamins, minerals, and protein. Prolonged very-low-calorie diets also slow your metabolism and cause muscle loss — the exact opposite of what most people want. If the calculator shows a weight-loss target below these floors, the tool automatically raises it to the minimum.
Choose your activity level honestly. Most people with desk jobs who exercise 3 times per week are "lightly active" (1.375), not "moderately active" (1.55). Overestimating activity by one level inflates your TDEE by 200-300 calories and can erase your entire calorie deficit. A good rule: if your total daily step count is under 7,500, you are sedentary regardless of gym sessions.
Protein is the most important macro to hit. Research supports 1.6-2.2 grams per kilogram of body weight (0.7-1.0 g per pound) for anyone strength-training during fat loss or muscle gain. Protein preserves muscle in a deficit, promotes satiety so you feel less hungry, and has the highest thermic effect of any macro (your body burns 20-30% of protein calories just digesting it). If your macro preset gives you less than 1.6 g/kg, increase the protein percentage.
What your calorie result means in practical terms: under 1,800 kcal/day for maintenance suggests you are either a small-framed person, sedentary, or older — this is normal. Between 2,000-2,500 is the most common range for moderately active adults. Above 3,000 is typical only for very active individuals, athletes, or tall/heavy people. If your result seems surprisingly high or low, double-check your height, weight, and activity level inputs.
If you are losing weight and hit a plateau after 4-6 weeks, do not cut more calories immediately. First, check if your activity level has dropped (you move less when eating less — this is called adaptive thermogenesis). Increase step count to 8,000-10,000 per day, ensure you are sleeping 7+ hours, and reassess after two more weeks before reducing intake further.
Use the macro presets as a framework, not as doctrine. The Balanced preset (30/40/30) works for most people. Low Carb (40/20/40) suits people who feel more satisfied on higher-fat diets. High Protein (40/35/25) is designed for serious lifters in a cutting phase. Keto (20/5/75) requires strict carb restriction under 50 g/day and should only be attempted if you have researched the adaptation period and potential side effects.

Calorie Calculator — Frequently Asked Questions

How many calories should I eat a day to lose weight?

To lose weight, eat 500 calories below your TDEE (Total Daily Energy Expenditure). This creates a deficit that produces roughly 1 lb (0.45 kg) of fat loss per week. For most adults, this translates to 1,500-2,200 calories per day depending on size and activity level. Never go below 1,200 calories (women) or 1,500 calories (men) without medical supervision — below these floors you risk nutrient deficiencies, muscle loss, and metabolic slowdown.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to keep your organs functioning, your heart beating, and your lungs breathing. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor that accounts for all movement throughout the day, including exercise. TDEE is always higher than BMR. For a sedentary person, TDEE is about 20% above BMR; for a very active person, it can be 70% or more above BMR.

Is the Mifflin-St Jeor equation more accurate than Harris-Benedict?

Yes. A 2005 systematic review by Frankenfield et al. in the Journal of the American Dietetic Association compared four predictive equations and found that Mifflin-St Jeor predicted resting metabolic rate within 10% of measured values in more individuals than Harris-Benedict, Owen, or WHO/FAO formulas. The difference is about 5% on average. Mifflin-St Jeor was published in 1990 using modern population data, while Harris-Benedict dates from 1919.

When should I use the Katch-McArdle formula instead?

Use Katch-McArdle when you know your body fat percentage. The formula uses lean body mass (BMR = 370 + 21.6 x LBM in kg) instead of total weight, making it more accurate for muscular people, athletes, or anyone with an above-average or below-average body fat level. For example, two men both weighing 200 lb at 5'10" — one at 12% body fat and the other at 30% — have very different lean mass and therefore very different calorie needs. Mifflin-St Jeor gives them the same BMR; Katch-McArdle does not.

What are macros and how do I split them?

Macros (macronutrients) are the three calorie-containing nutrients: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). A common split for general fitness is 30% protein, 40% carbs, 30% fat. For weight loss with strength training, 40% protein, 35% carbs, 25% fat prioritizes muscle preservation. For keto, 20% protein, 5% carbs, 75% fat induces ketosis. The best split depends on your goal, food preferences, and training style — protein should always be at least 1.6 g per kilogram of body weight.

Is this calorie calculator accurate?

The Mifflin-St Jeor equation predicts BMR within 10% of laboratory-measured values for 70-82% of people. This means your true calorie need could be 150-200 calories above or below the calculated result. Factors like genetics, hormonal status, medications, and the thermic effect of food introduce individual variation. The calculator gives you a well-validated starting point — track your weight for 2-3 weeks and adjust by 100-200 calories if your weight trend does not match your goal.

How do I know which activity level to choose?

Sedentary: desk job, under 5,000 steps/day, no structured exercise. Lightly active: desk job plus light exercise 1-3 days/week or 5,000-7,500 steps/day. Moderately active: exercise 3-5 days/week and 7,500-10,000 steps/day. Very active: hard training 6-7 days/week or a physically demanding job. Extra active: professional athlete or manual labor plus daily training. When in doubt, choose one level lower — overestimating activity is the most common reason calorie calculators give results that are too high.

What is a safe calorie deficit per day?

A deficit of 500 calories per day is the standard recommendation, producing about 1 lb (0.45 kg) of weight loss per week. A more aggressive 750-1,000 calorie deficit speeds up fat loss but increases the risk of muscle loss, fatigue, and nutrient deficiency. Never drop total intake below 1,200 kcal (women) or 1,500 kcal (men). For people who are already lean (under 15% body fat for men, under 25% for women), a smaller deficit of 250-350 calories protects against metabolic adaptation and muscle loss.

Key Terms

TDEE (Total Daily Energy Expenditure)

The total number of calories your body burns in 24 hours, including basal metabolism, digestion, and all physical activity. TDEE equals BMR multiplied by an activity factor.

BMR (Basal Metabolic Rate)

The number of calories your body requires at complete rest to maintain vital functions like breathing, circulation, and cell repair. BMR typically accounts for 60-75% of total daily calorie expenditure.

Calorie Deficit

Consuming fewer calories than your TDEE. A 500-calorie daily deficit produces roughly 1 lb (0.45 kg) of fat loss per week, based on the principle that 1 lb of body fat stores approximately 3,500 calories.

Calorie Surplus

Consuming more calories than your TDEE. A moderate surplus of 200-500 calories supports muscle growth when combined with resistance training.

Macronutrients (Macros)

The three nutrients that provide calories: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). Macro ratios determine the composition of your diet at any given calorie level.

Lean Body Mass (LBM)

Total body weight minus fat mass. Includes muscle, bone, organs, and water. Used in the Katch-McArdle formula because metabolically active tissue drives calorie expenditure more than fat tissue.

Mifflin-St Jeor Equation

A BMR prediction formula published in 1990 that uses weight, height, age, and sex. Validated as the most accurate general-population equation by a 2005 systematic review in the Journal of the American Dietetic Association.

Katch-McArdle Equation

A BMR prediction formula that uses lean body mass instead of total weight: BMR = 370 + 21.6 x LBM (kg). More accurate than Mifflin-St Jeor for muscular or very lean individuals who know their body fat percentage.

Sources & References

Content verified by the Smart Calculators Team