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Calorie Calculator

Find out how many calories you need each day (your TDEE) to keep your weight steady, plus daily targets for losing or gaining weight slowly.

Level: Grades 6–7

  • Common Core standard 6.EE.A.2.cEvaluate expressions at specific values of their variables. Include expressions that arise from formulas used in real-world problems. Perform arithmetic operations, including those involving whole-number exponents, in the conventional order when there are no parentheses to specify a particular order (Order of Operations).
Printable worksheet

Calorie Calculator

Inputs
Units
Sex

The published equations have separate versions for males and females.

These equations were developed for adults.

Result

Calories to maintain weight (TDEE)

2,417 kcal/day

Estimated maintenance intake: about 2,417 kcal per day; about 1,917 kcal per day would aim for roughly 1 lb of loss a week. These are estimates; actual needs vary.

BMR (Mifflin-St Jeor)
1,758 kcal/day
Mild weight loss, about ½ lb/week (−250)
2,167 kcal/day
Weight loss, about 1 lb/week (−500)
1,917 kcal/day
Faster weight loss, about 2 lb/week (−1,000)
1,417 kcal/dayThis is below about 1,500 kcal/day. Health groups often advise against eating this little unless a doctor is guiding you.
Mild weight gain, about ½ lb/week (+250)
2,667 kcal/day
Weight gain, about 1 lb/week (+500)
2,917 kcal/day

See the step-by-step solution ↓

Daily calories at each activity level (kcal/day)
Daily calories at each activity level (kcal/day)
Activity levelMultiplierMaintainLose 1 lb/wkLose 2 lb/wkGain 1 lb/wk
Sedentary1.22,1091,6091,1092,609
Lightly active (your choice)1.3752,4171,9171,4172,917
Moderately active1.552,7242,2241,7243,224
Very active1.7253,0322,5322,0323,532
Extra active1.93,3402,8402,3403,840

Step-by-step solution

  1. Change your height to centimeters, because the formula uses metric units (1 in is exactly 2.54 cm)

    (5×12+10)×2.54=177.8 cm

  2. Change your weight to kilograms (1 lb is exactly 0.45359237 kg)

    180 lb×0.453592=81.647 kg

  3. Use the Mifflin-St Jeor formula for a male. It uses your weight in kg, height in cm and age in years

    BMR=10×W + 6.25×H − 5×A + 5

  4. Put your measurements into the formula

    10×81.647+6.25×177.8−5×35+5=1,757.7 kcal/day

  5. Multiply your BMR by the activity factor for your level (1.375) to add the calories you burn moving

    1,757.7×1.375=2,416.9 kcal/day

  6. To lose weight, eat less than you burn: take away 250, 500 or 1,000 kcal a day for a slow, steady or faster pace

    2,417−250=2,167; 2,417−500=1,917; 2,417−1,000=1,417

  7. To gain weight, eat more than you burn: add 250 or 500 kcal a day for a slow or steady pace

    2,417+250=2,667; 2,417+500=2,917

  8. The table does the same math for every activity level, from mostly sitting (× 1.2) to extra active (× 1.9)

    1,757.7×1.2=2,109 … 1,757.7×1.9=3,340

Test yourself

20 quick questions built from this calculator's formula: work out results, predict what happens when an input changes, and work backward from an answer. Every answer comes with the working.

Please note: This calculator gives a general screening estimate, not a diagnosis. Talk to a qualified healthcare professional about your individual health.

What this calculator does

Find out how many calories you need each day to keep your weight steady, lose it or gain it. The calculator estimates how many calories you burn on a typical day. That's called your total daily energy expenditure, or TDEE. It then gives you daily eating targets: one to stay where you are, ones to lose about ½, 1 or 2 lb a week, and ones to gain slowly. TDEE counts what your body burns at rest, plus everything you burn moving, exercising, working and digesting food. That's why it's the usual starting point for a 'maintenance' calorie number.

First the calculator estimates what you burn at rest, called your BMR. By default it uses the Mifflin-St Jeor formula, and you can also pick Harris-Benedict or Katch-McArdle. Then it multiplies that by a standard activity factor. A table shows the same numbers at every activity level, so you can see how much that choice matters. Every number is an average-based estimate for a healthy adult. It isn't a prescription or a diagnosis. Before you make a big change to how you eat, especially with a health condition, talk to a doctor or registered dietitian.

Where it's used

Why this math matters outside the classroom:

  • Activity factor. A BMR of 1,650 kcal times the moderately active factor of 1.55 gives a TDEE of about 2,558 kcal.
  • Gradual change. Subtracting 500 kcal from a TDEE of 2,560 kcal gives a daily target of 2,060 kcal.
  • Meal planning. People planning a week of meals use their TDEE as the daily calorie budget for keeping their weight steady.
  • Comparing equations. Students swap between Mifflin-St Jeor and Harris-Benedict to see how the choice of equation shifts the result.
  • Training seasons. Athletes recheck their numbers when training moves from the off-season to the competitive season.

Grade level and standards: Grades 6–7; Common Core State Standards for Mathematics 6.EE.A.2.c. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.

How to use it

  1. Pick US or metric units. Then enter your sex, age, height and weight.
  2. Choose the activity level that matches a typical week, not your most active one.
  3. Read your maintenance calories (TDEE) and the daily targets for losing or gaining weight at different speeds.
  4. Use the table to compare activity levels. Then adjust based on how your weight actually changes over several weeks.

What the inputs mean

Sex
The resting-calorie formulas use different numbers for men and for women.
Age
Enter whole years, 18 or over. The formulas were built from data on adults.
Activity level
Each activity level covers a wide range of people. Most people with desk jobs who exercise a few times a week fit 'lightly' or 'moderately active'. Picking a level that's too high is the most common reason a calorie estimate comes out too high.
Resting energy equation
Mifflin-St Jeor is the usual choice for adults. The updated Harris-Benedict formula tends to give a slightly higher number. Katch-McArdle skips sex and age and works from your lean body mass instead, which is everything that isn't fat. So it can only be as good as your body fat estimate.
Body fat
Only Katch-McArdle uses this. An estimate from the body fat calculator, a scale or a professional check is fine.

Formula and method

Mifflin-St Jeor BMR (male)   = 10 × W + 6.25 × H − 5 × A + 5
Mifflin-St Jeor BMR (female) = 10 × W + 6.25 × H − 5 × A − 161
Harris-Benedict 1984 BMR: male 88.362 + 13.397 W + 4.799 H − 5.677 A; female 447.593 + 9.247 W + 3.098 H − 4.330 A
Katch-McArdle BMR = 370 + 21.6 × lean body mass (kg)
TDEE = BMR × activity factor   (1.2, 1.375, 1.55, 1.725 or 1.9)
Loss targets = TDEE − 250, − 500 or − 1,000;  gain targets = TDEE + 250 or + 500

In the formulas, W is your weight in kilograms, H is your height in centimeters and A is your age in years. BMR is what you burn at rest. If you enter US units, the calculator converts them exactly first: 1 in = 2.54 cm and 1 lb = 0.45359237 kg.

Mifflin-St Jeor (1990) was built from healthy adults, some of normal weight and some with obesity. The Harris-Benedict version is the 1984 update by Roza and Shizgal. The activity factors are the standard multipliers used with these formulas. They run from 1.2 for a day spent mostly sitting to 1.9 for hard physical work plus training.

Eating 500 kcal a day less than you burn works out very roughly to 1 lb (about 0.5 kg) a week. That uses the common rule of about 3,500 kcal per pound, or 7,700 kcal per kilogram. A 250 kcal change is about half that pace, and 1,000 kcal is about double. In real life, change is usually slower than the rule says, because your body adjusts as your weight changes.

Worked example

A 35-year-old man, 5 ft 10 in and 180 lb, exercises two or three times a week (lightly active). He uses the default Mifflin-St Jeor formula.

  1. Convert: 177.8 cm and 81.647 kg.
  2. BMR = 10 × 81.647 + 6.25 × 177.8 − 5 × 35 + 5 = 1,757.7 kcal/day.
  3. TDEE = 1,757.7 × 1.375 = 2,416.9 kcal/day.
  4. Targets: slow loss (½ lb/week) 2,167; loss (1 lb/week) 1,917; faster loss (2 lb/week) 1,417, which gets a warning because it's below 1,500; slow gain 2,667; gain 2,917 kcal/day.
  5. From the table, the same man would need about 2,109 kcal/day if he sat most of the day, and about 2,724 if moderately active.

Result: He needs about 2,417 kcal per day to keep his weight steady. Eating about 1,917 kcal per day would aim for roughly 1 lb of loss a week.

Understanding the result

Treat the maintenance number as a first guess, and don't worry if it isn't perfect. If your weight holds steady for two to four weeks while you eat near that number, you're close. If your weight drifts, adjust by 100 to 200 kcal and watch again.

Eating very little is hard to keep up, and it can make it hard to get enough nutrients. Many health groups advise against going below about 1,200 kcal a day for women or 1,500 kcal a day for men without a doctor's guidance. This calculator warns you about any loss target below those levels. The 2 lb a week target often lands there for smaller or less active people.

The gain targets are for slow change. Eating a lot more than that mostly adds fat faster, not more muscle.

Assumptions and limitations

  • You're an adult in fairly steady health, and not pregnant or breastfeeding.
  • The activity level you chose matches an average week.
  • The calorie targets add or take away a fixed 250, 500 or 1,000 kcal a day. Results are rounded to the nearest kilocalorie.
  • The resting-calorie formulas give averages for groups of people. What you burn at rest can differ by 10% or more.
  • Activity levels are rough, and you pick your own, which adds more uncertainty. The activity table shows how wide that range is.
  • The weekly pace numbers use the 3,500 kcal per pound rule. It overstates loss over the long run, because you need fewer calories as your weight falls.
  • The calculator doesn't consider health conditions, medicines, pregnancy, breastfeeding, or the needs of athletes in heavy training.
  • It isn't meant for children or teens, who need extra energy to grow.

Frequently asked questions

How many calories should I eat a day?

To keep your weight steady, eat roughly your TDEE: what you burn at rest times an activity factor. For the lightly active 35-year-old man in the example (5 ft 10 in, 180 lb), that's about 2,417 kcal a day. A lightly active 35-year-old woman who is 5 ft 4 in and 150 lb comes out near 1,871 kcal. Your own number depends on all five inputs, which is why the calculator asks for them.

How many calories should I eat to lose 1 or 2 pounds a week?

The usual rule of thumb is to eat about 500 kcal a day less than you burn for 1 lb a week, or about 1,000 kcal less for 2 lb a week. So subtract those from your maintenance number. If that puts you below about 1,200 kcal (women) or 1,500 kcal (men), the calculator warns you. A slower pace or more activity is the usual alternative, and a healthcare professional can help you find what suits you.

What is the difference between BMR and TDEE?

BMR is what you burn at complete rest. TDEE adds everything else: moving around, exercise and the energy used to digest food. TDEE is the number to compare with what you eat. Eating only your BMR would mean a big shortfall for almost everyone.

Which activity level should I choose?

Pick the one that matches an ordinary week. If you're torn between two levels, choose the lower one. People tend to overestimate how active they are, and you can adjust later based on what your weight does. The table shows how much each step up adds.

Which formula is the most accurate?

For most adults, Mifflin-St Jeor has matched measured resting calories as well as or better than the older Harris-Benedict formula. That's why it's the default. Katch-McArdle can suit very lean or very muscular people who have a body fat estimate they trust. All three are estimates, and they often differ by 50 to 150 kcal a day.

Why is my weight loss slower than the calculator predicts?

The 3,500 kcal per pound rule assumes you always need the same calories. But you need fewer as you lose weight. Day-to-day changes in water weight can also hide fat loss for a while. Recalculate after every 10 lb or so of change, and judge your progress over several weeks rather than days.

How this calculator is checked

Method: Mifflin-St Jeor (1990) BMR equation by default; Harris-Benedict as revised by Roza and Shizgal (1984); Katch-McArdle lean-mass equation (370 + 21.6 × LBM); conventional activity factors (1.2, 1.375, 1.55, 1.725, 1.9); ±250/500 and −1,000 kcal offsets using the approximate 3,500 kcal/lb (7,700 kcal/kg) rule. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.

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