Calorie Calculator
Calculate your BMR, daily calorie needs (TDEE), and a full macro breakdown for weight loss, maintenance, or muscle gain
What Is a Calorie Calculator?
A calorie calculator estimates your daily calorie needs based on your age, gender, weight, height, and activity level. It first calculates your Basal Metabolic Rate (BMR) — the energy your body burns at complete rest — then multiplies it by an activity factor to estimate your Total Daily Energy Expenditure (TDEE), which is the number of calories you burn, and therefore need to eat, on a typical day.
How Calorie Needs Are Calculated
This calculator uses the Mifflin-St Jeor equation by default, one of the most accurate general-population formulas available. If you enter a body fat percentage in Advanced Options, it switches to the Katch-McArdle formula, which is based on lean body mass and tends to be more precise for people who know their body composition.
BMR Formulas Used
Mifflin-St Jeor (Male): BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Mifflin-St Jeor (Female): BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Katch-McArdle (if body fat % entered): BMR = 370 + 21.6 × Lean Body Mass(kg)
TDEE: BMR × Activity Multiplier
Explanation of Every Input
Age, Gender, Weight & Height
These four inputs feed directly into the BMR formula. Advanced Options lets you enter weight in pounds and height in inches instead of the metric defaults — the calculator converts everything internally so results stay accurate.
Activity Level
Activity level is a multiplier applied to BMR to approximate a typical week of movement and exercise, ranging from Sedentary (1.2×) up to Extra Active (1.9×). Choosing an accurate level is one of the biggest factors in getting a realistic calorie target.
Body Fat % (Optional)
If you know your approximate body fat percentage, entering it switches the calculation to the Katch-McArdle formula, which is generally more accurate for people who are leaner or more muscular than average.
Macro Split
The macro split determines how your calorie target is divided between protein, carbohydrates, and fat. Balanced suits most goals; High Protein helps preserve muscle during a deficit; Low Carb and High Carb suit specific dietary preferences.
Understanding Your Results
BMR (Basal Metabolic Rate)
The calories your body needs just to perform basic functions like breathing, circulation, and cell production, before any activity is added.
TDEE / Maintenance Calories
Total calories needed to maintain your current weight, combining BMR with your selected activity level.
Weight Loss Targets
Mild (-250), Moderate (-500), and Extreme (-1000) calorie deficits below maintenance, shown so you can pick a sustainable pace.
Weight Gain Targets
Mild (+250), Moderate (+500), and Fast (+1000) calorie surpluses above maintenance for lean or faster weight gain.
How to Reduce Weight Loss Plateaus
- Recalculate your targets every 4-6 weeks, since BMR and TDEE both drop as body weight decreases.
- Avoid stacking a separate gym-tracker calorie count on top of an already-active activity level.
- Prioritize protein intake to help preserve muscle mass during a calorie deficit.
- Choose a moderate deficit (around 500 calories) for a pace that is easier to sustain long-term.
Advantages of Using This Calculator
- Instantly compares maintenance, loss, and gain calorie targets side by side.
- Includes a full macro (protein/carb/fat) breakdown for each goal, in grams.
- Supports metric or imperial units, and an optional body-fat-based formula.
- Visualizes results with a macro chart and a calorie-by-goal comparison chart.
Limitations
- Results are estimates; individual metabolism can vary by 5-10% or more.
- Does not account for medical conditions, medications, or hormonal factors affecting metabolism.
- Activity level is a rough average and does not track day-to-day variation.
Common Mistakes to Avoid
- Selecting an activity level higher than your actual typical week.
- Eating at an extreme deficit for extended periods, which can be hard to sustain.
- Not recalculating targets as your weight changes over time.
- Ignoring protein intake while focused only on the total calorie number.
Worked Examples
Active Male, Sedentary Job
Profile: Male, 25 years, 80 kg, 180 cm
Activity Level: Sedentary (little or no exercise)
BMR: 1,805 cal
Maintenance (TDEE): 2,166 cal
Macros at Maintenance (Balanced): Protein 162 g, Carbs 217 g, Fat 72 g
A young, larger-framed man at a sedentary activity level still has a relatively high BMR, but the low activity multiplier keeps total daily needs moderate.
Moderately Active Woman
Profile: Female, 35 years, 65 kg, 165 cm
Activity Level: Moderately Active (3-5 days/week)
BMR: 1,345 cal
Maintenance (TDEE): 2,085 cal
Macros at Maintenance (Balanced): Protein 156 g, Carbs 209 g, Fat 70 g
Regular exercise 3-5 days a week adds a meaningful amount on top of BMR, bringing total daily needs well above maintenance-at-rest.
Very Active Male
Profile: Male, 40 years, 90 kg, 175 cm
Activity Level: Very Active (6-7 days/week)
BMR: 1,799 cal
Maintenance (TDEE): 3,104 cal
Macros at Maintenance (Balanced): Protein 233 g, Carbs 310 g, Fat 103 g
Frequent, intense training pushes the activity multiplier much higher, nearly doubling BMR to arrive at total daily calorie needs.
Lightly Active Younger Woman
Profile: Female, 28 years, 58 kg, 160 cm
Activity Level: Lightly Active (1-3 days/week)
BMR: 1,279 cal
Maintenance (TDEE): 1,759 cal
Macros at Maintenance (Balanced): Protein 132 g, Carbs 176 g, Fat 59 g
A smaller body frame with light activity produces a lower BMR and TDEE, so calorie targets for any goal will naturally be smaller too.
Frequently Asked Questions
How accurate is this calorie calculator?
This calculator uses the Mifflin-St Jeor equation (or Katch-McArdle if you enter body fat percentage), which are among the most reliable formulas available for estimating calorie needs. Actual needs can still vary by 5-10% due to genetics, muscle mass, hormones, and daily activity that is hard to measure precisely.
What is BMR and how is it different from TDEE?
BMR (Basal Metabolic Rate) is the energy your body burns at complete rest just to keep vital functions running. TDEE (Total Daily Energy Expenditure) adds your daily activity and exercise on top of BMR, giving the actual number of calories you burn — and therefore need to eat — in a typical day.
Which formula does this calculator use — Mifflin-St Jeor or Katch-McArdle?
By default it uses the Mifflin-St Jeor equation, widely considered the most accurate formula for the general population. If you enter your body fat percentage in Advanced Options, it automatically switches to the Katch-McArdle formula, which uses lean body mass and tends to be more precise for people who know their body composition.
How many calories should I eat to lose weight?
A moderate deficit of 500 calories per day below your maintenance level typically produces about 0.5 kg (1 lb) of weight loss per week, which is considered sustainable. Larger deficits speed up short-term results but are harder to maintain and can increase muscle loss, so this calculator also shows mild (250 cal) and extreme (1000 cal) options for comparison.
How many calories should I eat to gain weight or build muscle?
A surplus of 250-500 calories per day above maintenance supports steady, mostly lean weight gain, while larger surpluses (1000+ calories) speed up gain but add more fat along with muscle. Pairing any surplus with resistance training improves the ratio of muscle to fat gained.
What do the macro percentages (protein, carbs, fat) mean?
Macronutrient splits divide your total calories among protein, carbohydrates, and fat, each measured in grams (protein and carbs provide 4 calories per gram, fat provides 9). The Balanced split (30/40/30) suits most goals, while High Protein favors muscle retention during a deficit and Low Carb suits those who prefer fewer carbohydrates.
Why does my activity level make such a big difference?
Activity level is multiplied against your BMR, so moving from Sedentary to Very Active can add 500-1000+ calories to your daily needs. Choosing an activity level that is too high is one of the most common reasons people plateau or gain weight unexpectedly while "eating to their calculator number."
Does this calculator account for exercise calories separately?
No — the activity level you select already estimates a general amount of daily movement and exercise, so it should reflect your typical week rather than being stacked with a separate gym tracker figure. Manually adding exercise-app calories on top of an already-active activity level commonly overestimates calorie needs.
Is a 1,200 calorie diet safe?
Very low calorie targets below roughly 1,200 (women) or 1,500 (men) are generally not recommended without medical supervision, since they can be difficult to sustain and may not provide adequate nutrition. If your calculated deficit target falls near or below these levels, consider a smaller deficit or professional guidance instead.
Why did my weight loss slow down even though I am eating the same calories?
As you lose weight, your BMR and TDEE both decrease because a smaller body requires fewer calories to maintain — a normal process called metabolic adaptation. Recalculating your targets every 4-6 weeks, or after a meaningful weight change, keeps your calorie target aligned with your current body size.
Should I use kilograms or pounds, centimeters or inches?
Either works — Advanced Options lets you switch the weight unit to pounds and the height unit to inches, and the calculator converts everything internally before running the formula, so results are identical regardless of which units you enter.
How is protein, carb, and fat "grams" calculated from my calorie target?
Each macro percentage of your total calorie target is converted into grams using its calorie value: protein and carbohydrates each provide 4 calories per gram, while fat provides 9 calories per gram. For example, 30% of a 2,000-calorie target is 600 calories of protein, which equals 150 grams (600 ÷ 4).
Conclusion
Knowing your BMR and TDEE turns weight management into a numbers problem you can actually plan around, rather than guesswork. Use this calculator to find your maintenance calories, compare loss and gain targets, and build a macro plan that fits your goal — then recheck it every few weeks as your weight changes.