A calorie calculator is a free online tool that estimates your daily calorie needs from your body weight, body height, age, sex, and activity level. It computes your basal metabolic rate (BMR) with a published equation — Mifflin-St Jeor, the revised Harris-Benedict Equation, or the Katch-McArdle Formula — then applies an activity factor multiplied against that resting daily energy to produce your total daily energy expenditure (TDEE), the calories you burn in a day.
The main benefit is accurate calorie estimation in seconds. A calorie calculator estimate replaces guesswork with a personalized calorie plan for weight loss goals, weight maintenance calories, or muscle gain, and it supports calorie counting for weight loss without a food scale for the first step.
The main uses are setting a calorie deficit or calorie surplus, finding maintenance calories, and building a macro calorie split of protein, fat, and carbohydrates. Athletes, dieters, and anyone tracking healthy weight management use the same four inputs.
The calculator has four parts: the input fields for weight, height, age, sex, and body fat percentage; the BMR formula; the activity factor; and the output — your daily calorie target with macronutrient distribution. Enter your numbers above to see all four in the label.
How to Calculate Calories
To calculate calories, estimate your BMR, multiply it by an activity factor for your TDEE, subtract or add calories for your goal, then divide the target across protein, fat, and carbohydrates. Four steps produce a complete daily calorie plan.
Step 1: Calculate Basal Metabolic Rate (BMR)
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to run your heart, lungs, brain, and body temperature. BMR is 60–70% of daily calorie needs for most adults and is the calories burned in a day without exercise. Three equations calculate it.
The Mifflin-St Jeor Equation is the most accurate general-purpose formula for healthy adults and is the calculator default.
Mifflin-St Jeor Equation
Men: BMR = 10W + 6.25H − 5A + 5
Women: BMR = 10W + 6.25H − 5A − 161
W = weight (kg) · H = height (cm) · A = age (years)
The revised Harris-Benedict Equation is the 1984 revision of the 1919 original. It was the standard until 1990, when Mifflin-St Jeor was introduced, and it returns a slightly higher resting daily energy.
Revised Harris-Benedict Equation
Men: BMR = 13.397W + 4.799H − 5.677A + 88.362
Women: BMR = 9.247W + 3.098H − 4.330A + 447.593
W = weight (kg) · H = height (cm) · A = age (years)
The Katch-McArdle Formula calculates resting daily energy expenditure (RDEE) from lean body mass. It is the most accurate option for lean users who know their body fat percentage, because it accounts for body composition instead of total weight.
Katch-McArdle Formula
BMR = 370 + 21.6 × (1 − F) × W
W = weight (kg) · F = body fat (decimal, e.g. 0.20 for 20%)
Worked example: a 30-year-old woman weighs 150 lbs (68.2 kg) and stands 165 cm. Mifflin-St Jeor gives BMR = 10 × 68.2 + 6.25 × 165 − 5 × 30 − 161 = 682 + 1,031 − 150 − 161 = 1,402 calories per day at rest.
Calculator results are estimates based on population averages. Measured resting metabolic rate varies with genetics, muscle mass, hormones, and medications, so treat the number as a starting point and adjust it against two weeks of scale data.
Step 2: Determine Total Daily Energy Expenditure (TDEE)
Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor between 1.2 and 1.95. TDEE is your maintenance calories — the energy that holds your body weight stable. Pick the activity level that matches your honest weekly routine.
| Activity level | Multiplier |
|---|---|
| Sedentary — little to no exercise | BMR × 1.2 |
| Lightly active — light exercise 1–3 days/week | BMR × 1.375 |
| Moderately active — moderate exercise 3–5 days/week | BMR × 1.55 |
| Very active — hard exercise 6–7 days/week | BMR × 1.725 |
| Super active — very hard exercise plus a physical job | BMR × 1.9 |
| Most people overestimate activity by one level. Desk job plus three workouts is Lightly active. | |
Activity level definitions set the boundaries: exercise means 15–30 minutes of raised heart rate activity, intense exercise means 45–120 minutes, and very intense exercise means 2 or more hours. Non-exercise activity thermogenesis boost — the calories from walking, standing, and fidgeting — sits inside this multiplier, which is why an accurate activity factor matters.
Worked example: the 1,402-calorie BMR above at Lightly active gives TDEE = 1,402 × 1.375 = 1,928 calories per day. That estimated energy requirement is the woman's maintenance calories.
Step 3: Set Your Goal Weight and Time Frame
Create a calorie deficit of 500 calories per day to lose about 1 pound (0.45 kg) per week, or 1,000 calories per day to lose about 2 pounds (0.9 kg) per week — the upper safe limit. 1 pound of body fat holds about 3,500 calories, so a 500-calorie daily deficit removes roughly 3,500 calories across a week.
Worked example: Sara weighs 150 lbs and wants to lose 20 lbs. 150 lbs − 20 lbs = 130 lbs goal weight. 20 lbs at 2 lbs per week = 10 weeks. Her deficit target is 1,000 calories per day under TDEE for that timeline.
For muscle gain, eat a calorie surplus of 250–500 calories per day above TDEE. Building 1 pound of muscle takes roughly 2,500–2,700 calories plus resistance training, so a modest surplus limits fat gain. Zigzag calorie cycling — higher-calorie days on training days and lower-calorie days on rest days — hits the same weekly average while matching intake to demand.
Do not reduce intake by more than 1,000 calories per day. Consult a doctor or registered dietitian nutritionist (RDN) before any deficit over 2 lbs per week. The Centers for Disease Control and Prevention (CDC) recommends 1–2 lbs per week, not 5 lbs per week.
Step 4: Break Down Macronutrient Ratios
Divide your daily calorie target into three macronutrients: protein, fat, and carbohydrates. Protein and carbohydrates supply 4.1 calories per gram and fat supplies 8.8 calories per gram, so the same calorie total can be split many ways. Convert macros to calories by multiplying grams by these values.
| Component | kJ/g | kcal/g | kJ/oz | kcal/oz |
|---|---|---|---|---|
| Fat | 37 | 8.8 | 1,049 | 249 |
| Proteins | 17 | 4.1 | 482 | 116 |
| Carbohydrates | 17 | 4.1 | 482 | 116 |
| Fiber | 8 | 1.9 | 227 | 54 |
| Ethanol (alcohol) | 29 | 6.9 | 822 | 196 |
| Organic acids | 13 | 3.1 | 369 | 88 |
| Polyols | 10 | 2.4 | 283 | 68 |
Protein
Protein supplies 4.1 calories per gram. Eat 1–1.2 g/kg/day if sedentary or lightly active and 1.4–2.2 g/kg/day if moderately-to-extremely active. Worked example: 150 lbs ÷ 2.2 = 68.2 kg, then 68.2 kg × 1.2 = 82 g and 68.2 kg × 2.2 = 150 g. Protein has the highest thermic effect of food, so thermic effect protein optimization raises the calories burned during digestion and helps preserve lean body mass in a deficit.
Fat
Fat supplies about 9 calories per gram (8.8 kcal/g precisely). Eat a minimum of 1 g/kg/day and 20–35% of total daily calories, per the Dietary Guidelines for Americans. Worked example: 2,000 calories × 0.30 = 600 calories from fat, then 600 ÷ 9 = 67 g. Dietary fat carries the fat-soluble vitamins A, D, E, and K, so intake below the minimum reduces their absorption.
Carbohydrates
Carbohydrates supply 4.1 calories per gram. Eat 45–65% of daily calories from carbohydrates and divide carbohydrate calories by 4 for grams. Worked example: 2,000 calories × 0.50 = 1,000 calories, then 1,000 ÷ 4 = 250 g. Fiber intake counts inside this total but yields only 1.9 calories per gram. Insulin sensitivity carb cycling — more carbohydrates on training days — suits people managing blood sugar around exercise.
How Many Calories Do You Need?
Adult males need 2,000–3,000 calories per day and adult females need 1,600–2,400 calories per day, per the U.S. Department of Health. Exact needs depend on age, body weight, body composition, and physical activity, and the range within each group is wide.
Average Calorie Needs
Average calorie needs rise with body size and physical activity and fall with age. The Dietary Guidelines for Americans (2020–2025) list daily ranges by age and sex, from sedentary at the low end to active at the high end.
Females
| Age | Sedentary | Active |
|---|---|---|
| 19–30 years | 1,800 | 2,400 |
| 31–60 years | 1,600 | 2,200 |
| 61+ years | 1,600 | 2,200 |
Pregnant and nursing people need significantly more calories, and the standard estimates do not apply. Second-trimester needs rise by about 340 calories per day and third-trimester needs by about 450, while breastfeeding adds roughly 450–500 calories per day for postpartum recovery calorie needs. After menopause, resting metabolic rate declines, so post-menopausal metabolism tracking and a woman over 50 both point toward the lower end of each range.
Males
| Age | Sedentary | Active |
|---|---|---|
| 19–30 years | 2,400 | 3,000 |
| 31–60 years | 2,200 | 3,000 |
| 61+ years | 2,000 | 2,600 |
Children
Children need 1,000–3,200 calories per day, depending on age and sex. A 9 year old boy falls in the 1,600–2,600 band and a 9 year old girl in the 1,400–2,200 band; an 8 year old sits one band lower at 1,200–2,000 (boys) and 1,200–1,800 (girls).
| Age | Male | Female |
|---|---|---|
| 2–4 years | 1,000–1,600 | 1,000–1,400 |
| 5–8 years | 1,200–2,000 | 1,200–1,800 |
| 9–13 years | 1,600–2,600 | 1,400–2,200 |
| 14–18 years | 2,000–3,200 | 1,800–2,400 |
Cutting a child's calorie intake risks nutritional deficiencies, slowed growth, and disordered eating. Change a child's diet only with a pediatrician or registered dietitian (RD).
Calories: Different Kinds and Their Effects
1 Calorie (kcal) equals 4,184 joules or 4.184 kilojoules. A food Calorie written with a capital C is a kilocalorie — 1,000 small calories — so the numbers on a nutrition label are kilocalories.
Calories in versus calories out drives body weight: eat fewer than you burn and you lose weight, eat more and you gain. Net calories are calories eaten minus calories burned. Active calories are the calories burned through movement above resting daily energy, while total calories add BMR to active calories.
Calorie quality changes the effect. Empty calories from added sugar and alcohol carry energy with few nutrients, while nutrient-dense low-calorie foods carry vitamins and fiber. Calories from drinks make up about 21% of a typical person's diet, so beverages are the fastest place to cut. Metabolic flexibility fuel switching — the body moving between fat and carbohydrate fuel — improves with regular exercise and steady meal timing.
Convert units by multiplying kcal by 4.184 for kilojoules: 500 kcal = 2,092 kJ. For food comparisons, 84 calories is a small snack — about one large boiled egg (78 calories) — while 84 grams of celery holds only about 13 calories, and 86 calories is roughly one medium apple minus a few bites. To convert calories to grams of a macronutrient, divide by 4 for protein or carbohydrates and by 9 for fat.
Calories in Common Foods
The tables below list calories and kilojoules per common serving across eight food groups. Weigh portions with a digital kitchen scale and log them in a food diary app for accuracy. A recipe calorie calculator sums ingredient calories for homemade food, and major restaurants — Chipotle, Starbucks, McDonald's — publish calories per menu item for eating out.
Fruits
| Food | Serving | Calories | kJ |
|---|---|---|---|
| Apple | 1 medium (182 g) | 95 | 397 |
| Banana | 1 medium (118 g) | 105 | 439 |
| Orange | 1 medium (131 g) | 62 | 259 |
| Grapes | 1 cup (151 g) | 104 | 435 |
| Strawberries | 1 cup (152 g) | 49 | 205 |
Vegetables
| Food | Serving | Calories | kJ |
|---|---|---|---|
| Broccoli | 1 cup (91 g) | 31 | 130 |
| Celery | 100 g | 16 | 67 |
| Carrot | 1 medium (61 g) | 25 | 105 |
| Spinach | 1 cup (30 g) | 7 | 29 |
| Baked potato | 1 medium (173 g) | 161 | 674 |
Grains & Cereals
| Food | Serving | Calories | kJ |
|---|---|---|---|
| Oatmeal, cooked | 1 cup (234 g) | 154 | 644 |
| White rice, cooked | 1 cup (158 g) | 205 | 858 |
| Whole-wheat bread | 1 slice (28 g) | 69 | 289 |
| Pasta, cooked | 1 cup (140 g) | 221 | 925 |
| Quinoa, cooked | 1 cup (185 g) | 222 | 929 |
Proteins
| Food | Serving | Calories | kJ |
|---|---|---|---|
| Eggs | 2 large (100 g) | 143 | 598 |
| Chicken breast, cooked | 100 g | 165 | 690 |
| Salmon | 100 g | 208 | 870 |
| Ground beef, 85% lean | 100 g | 250 | 1,046 |
| Tofu | 100 g | 76 | 318 |
| Lentils, cooked | 1 cup (198 g) | 230 | 962 |
Dairy & Alternatives
| Food | Serving | Calories | kJ |
|---|---|---|---|
| Whole milk | 1 cup (244 g) | 149 | 623 |
| Greek yogurt, plain | 170 g | 100 | 418 |
| Cheddar cheese | 28 g | 115 | 481 |
| Almond milk, unsweetened | 1 cup | 30 | 126 |
| Cottage cheese | 1 cup (226 g) | 206 | 862 |
Fats & Oils
| Food | Serving | Calories | kJ |
|---|---|---|---|
| Olive oil | 1 tbsp (14 g) | 119 | 498 |
| Butter | 1 tbsp (14 g) | 102 | 427 |
| Almonds | 28 g (23 nuts) | 164 | 686 |
| Avocado | 1/2 medium (68 g) | 114 | 477 |
| Peanut butter | 2 tbsp (32 g) | 188 | 787 |
Sweets & Snacks
| Food | Serving | Calories | kJ |
|---|---|---|---|
| Milk chocolate | 1 bar (43 g) | 235 | 983 |
| Potato chips | 28 g | 152 | 636 |
| Chocolate chip cookie | 1 (16 g) | 78 | 326 |
| Vanilla ice cream | 1/2 cup (66 g) | 137 | 573 |
| Glazed doughnut | 1 (60 g) | 260 | 1,088 |
Beverages
| Drink | Serving | Calories | kJ |
|---|---|---|---|
| Water | any | 0 | 0 |
| Black coffee | 1 cup | 2 | 8 |
| Orange juice | 1 cup (248 g) | 112 | 469 |
| Cola | 12 oz (355 ml) | 136 | 569 |
| Beer | 12 oz (355 ml) | 153 | 640 |
| Red wine | 5 oz (147 ml) | 125 | 523 |
| Drinks supply about 21% of a typical diet's calories. | |||
Sample Meal Plans
Three sample meal plans hit 2,000, 1,500, and 1,200 calories across breakfast, a snack, lunch, a snack, and dinner. Each plan front-loads protein to control hunger and keeps whole foods over ultra-processed ones.
2000 Calorie Meal Plan
| Meal | Food | Calories |
|---|---|---|
| Breakfast | Oatmeal with banana and almonds | 420 |
| Snack | Greek yogurt with berries | 180 |
| Lunch | Chicken, rice, and broccoli bowl | 550 |
| Snack | Apple with peanut butter | 270 |
| Dinner | Salmon, quinoa, and salad | 580 |
| Total | 2,000 |
1500 Calorie Meal Plan
| Meal | Food | Calories |
|---|---|---|
| Breakfast | Two eggs with whole-wheat toast | 290 |
| Snack | Cottage cheese with strawberries | 160 |
| Lunch | Turkey and vegetable wrap | 380 |
| Snack | Almonds (28 g) | 170 |
| Dinner | Tofu stir-fry with brown rice | 500 |
| Total | 1,500 |
1200 Calorie Meal Plan
| Meal | Food | Calories |
|---|---|---|
| Breakfast | Greek yogurt with oats and berries | 250 |
| Snack | Carrot sticks and hummus | 120 |
| Lunch | Grilled chicken salad | 350 |
| Snack | One medium apple | 100 |
| Dinner | Baked cod with vegetables | 380 |
| Total | 1,200 | |
| 1,200 calories is the short-term floor for women, not a long-term target. | ||
Calories Burned from Common Exercises
A 155-pound (70 kg) person burns about 596 calories in an hour of running at 6 mph. Calorie burn rises with body weight and intensity, so a heavier person burns more for the same activity. The table lists calories burned in one hour at three body weights, from Harvard Health Publications.
| Exercise | 125 lb | 155 lb | 185 lb |
|---|---|---|---|
| Walking, 3.5 mph | 240 | 298 | 355 |
| Running, 6 mph | 480 | 596 | 710 |
| Cycling, moderate | 480 | 596 | 710 |
| Swimming laps | 423 | 528 | 632 |
| Elliptical trainer | 540 | 670 | 800 |
| Weightlifting | 180 | 224 | 266 |
| Jump rope | 570 | 707 | 844 |
| Rowing, vigorous | 510 | 632 | 755 |
| Stair machine | 540 | 670 | 800 |
10,000 steps burn about 300–500 calories for most adults. 9,000 steps (9k steps) cover roughly 4 miles (6.4 km) and burn about 270–450 calories, and 20,000 steps burn about 600–1,000 calories. Exact numbers scale with body weight, stride, and pace.
A calories-burned calculator based on heart rate reads your workout intensity in real time. Devices estimate the same way: the Apple Watch and Fitbit calculate calories burned from heart rate, movement, and your body profile, and their estimates carry a 10–20% error. Treat wearable calories as a trend, not a precise count, and do not eat all of them back.
How to Reduce Calorie Intake
Five methods reduce calorie intake without constant hunger: eat more protein, limit sugary drinks, drink more water, exercise, and cut refined carbs and ultra-processed foods.
1. Eat More Protein
Increase protein to 1.6–2.2 g/kg of body weight per day. Protein is the most filling macronutrient, carries the highest thermic effect of food, and protects muscle during a calorie deficit, so a higher-protein plate lowers total intake without extra willpower.
2. Limit Sugary Drinks
Cut soda, juice, and sweetened coffee. Drinks supply about 21% of a typical diet's calories and pass through with little fullness, so a person can drink 500 empty calories and still feel hungry. Swapping one 12 oz (355 ml) cola for water saves 136 calories each time.
3. Drink More Water
Drink water before meals to blunt appetite. For each pound (0.45 kg) of weight lost, drink around 16–20 oz (0.5–0.6 liters) of water to stay hydrated. Water carries zero calories and often replaces higher-calorie drinks.
4. Exercise
Move daily to raise total daily energy expenditure. Resistance training preserves lean body mass in a deficit, and a non-exercise activity thermogenesis boost from walking and standing adds calories burned without structured workouts. Exercise improves cardiovascular health alongside the calorie burn.
5. Reduce Intake of Refined Carbs and Ultra-Processed Foods
Replace white bread, pastries, and packaged snacks with whole foods. Ultra-processed foods pack many calories into small portions with little fiber, so they raise intake before fullness registers. Whole grains, vegetables, and lean proteins carry more volume per calorie and steady blood sugar.
Weight Loss Tips
Steady weight loss comes from a consistent calorie deficit, high protein, and honest tracking. Seven habits keep the deficit intact week to week.
- Track every day with MyFitnessPal, Lose It!, Cronometer, or FatSecret to catch the 300–500 calories most people miss.
- Weigh yourself under the same conditions a few mornings a week and read the weekly average, not the daily number.
- Eat protein at every meal to stay full on fewer calories.
- Sleep 7–9 hours, since poor sleep quality lowers metabolic rate and raises appetite the next day.
- Plan for events, because a weekly average matters more than any single high-calorie day.
- Keep a digital kitchen scale on the counter to make accurate logging automatic.
- Adjust by 100–200 calories after two flat weeks rather than making a large cut.
Timeline example: a person losing 1 lb (0.45 kg) per week loses 6 lbs in 6 weeks and about 12 lbs in 3 months. Faster loss on paper usually means water and muscle, not fat, so patience protects the result.
Potential Downsides of Counting Calories
Calorie counting has three downsides: measurement error, obsessive tracking, and the risk of disordered eating. Each one weakens the result or the person behind it.
Measurement error is built in. Self-reported tracking runs 20–40% low for most people, and every calorie figure is a population average, not a lab measurement, so the scale trend corrects the estimate over time. This is the leading reason a person is not losing weight in a calorie deficit.
Calorie-tracking apps carry a risk of disordered eating. Stop tracking and speak with a doctor or registered dietitian nutritionist (RDN) if logging becomes obsessive, if meals cause anxiety, or if the number overrides hunger and fullness. Leptin resistance appetite regulation and cortisol management stress eating also shift real needs, so rigid targets do not fit every day.