Health & fitness
Calorie Calculator
This calculator estimates how many calories you should eat each day to reach a specific goal — losing weight, holding steady, or gaining. Enter your sex, age, height, weight and activity level in U.S. customary units (feet, inches and pounds) or metric, pick a goal, and it works out your maintenance calories (TDEE) from the Mifflin-St Jeor equation, then adds or subtracts a daily amount to match your target. Weight change comes down to energy balance: eat fewer calories than you burn and you lose, eat more and you gain. The standard rule of thumb is that about 3,500 calories equals roughly one pound of body fat, so a 500-calorie daily deficit aims at about a pound a week. It updates as you type, runs entirely in your browser, and shows the math below. This is general information only, not medical advice — consult a licensed professional before changing your diet.
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These are estimates, not a diagnosis. Don't eat below about 1,500 calories (men) or 1,200 (women) without professional guidance.
How the calorie calculator works
The tool runs in three steps. First it finds your BMR with the Mifflin-St Jeor equation. Then it multiplies BMR by your activity factor to get your maintenance calories (TDEE). Finally it adds or subtracts a daily amount for your goal to produce your target. Imperial inputs are converted to metric first, so the result is identical either way.
calorie target formula
Target = (BMR × activity) + goal adjustment BMR (men) = 10W + 6.25H − 5A + 5 BMR (women) = 10W + 6.25H − 5A − 161where: W = weight in kg, H = height in cm, A = age in years activity = 1.2 (sedentary) to 1.9 (extra active) goal: −500 cal/day ≈ lose 1 lb/week; +500 ≈ gain 1 lb/week (based on ≈ 3,500 calories per pound of fat)
Notes & assumptions
- The 3,500-calories-per-pound rule is a useful approximation, not an exact law of physics.
- Very large deficits can backfire — slower, steadier loss is easier to keep off.
- Calculations are for general information only and are not medical advice — consult a healthcare professional before changing your diet.
Worked example: from stats to a weekly plan
Numbers make the three steps concrete, so walk through one person end to end. Take a 35-year-old woman who is 5 ft 6 in tall, weighs 160 lb and is lightly active: she walks the dog most days and fits in one or two gym sessions a week, but works at a desk. Converting to metric gives a height of 66 × 2.54 = 167.64 cm and a weight of 160 ÷ 2.2046 = 72.57 kg.
Step 1: BMR. The women's Mifflin-St Jeor formula is 10W + 6.25H − 5A − 161. Plugging in: 10 × 72.57 + 6.25 × 167.64 − 5 × 35 − 161 = 725.7 + 1,047.8 − 175 − 161, which comes to about 1,437 calories a day at complete rest. (Every figure in this example is rounded to the nearest whole calorie; the tool itself computes at full precision.)
Step 2: TDEE. Multiply BMR by the lightly active factor of 1.375: 1,437.5 × 1.375 ≈ 1,977 calories. That is her estimated maintenance level, the intake at which her weight typically holds steady.
Step 3: the goal. To lose weight at a moderate pace she subtracts 500 calories a day, landing at a target of about 1,477 calories. Across a week that is a 3,500-calorie shortfall, and since roughly 3,500 calories corresponds to about one pound of body fat, the target aims at around one pound of loss per week. Treat that pace as an approximation rather than a promise: metabolism adapts as weight drops, and real-world results typically drift from the paper math after a month or two.
Activity multipliers, translated into real weeks
The activity factor is the biggest lever in the whole calculation and the easiest one to get wrong, because most people rate their week by its most active day. The table below describes what each level typically looks like across a full week, along with the maintenance calories our example (BMR 1,437.5) would get at each one. Each TDEE is her BMR times the multiplier, rounded to the nearest calorie.
| Level | Multiplier | What a typical week looks like | Example TDEE |
|---|---|---|---|
| Sedentary | 1.2 | Desk job, driving or transit, no planned exercise; movement is mostly errands and housework | 1,725 cal/day |
| Lightly active | 1.375 | One to three easy sessions a week: brisk walks, a casual bike ride, a light gym visit | 1,977 cal/day |
| Moderately active | 1.55 | Three to five real workouts a week, or a job that keeps you on your feet much of the day | 2,228 cal/day |
| Very active | 1.725 | Hard training six or seven days a week, or a physical job combined with regular exercise | 2,480 cal/day |
| Extra active | 1.9 | Heavy manual labor plus daily training, two-a-day sessions, or endurance athletes in season | 2,731 cal/day |
Notice the spread: the same woman ranges from 1,725 to 2,731 maintenance calories, a gap of about 1,000 calories a day, purely on how her week is described. When you are honestly between two levels, pick the lower one; a conservative estimate that turns out slightly low is easy to correct upward after two weeks of tracking, while an inflated one quietly erases the deficit you thought you had.
Goal pacing: what each target implies per week
Each pace maps to a fixed daily adjustment against maintenance. Using the example's lightly active TDEE of 1,977 calories, here is what the common goals work out to. Daily targets are TDEE plus or minus the adjustment, rounded to the nearest calorie; the weekly column is the daily adjustment times seven, under the usual approximation that about 3,500 calories corresponds to one pound of body fat.
| Goal | Daily adjustment | Daily target | Weekly energy difference |
|---|---|---|---|
| Maintain weight | 0 | 1,977 cal | 0 |
| Lose 0.5 lb/week | −250 cal | 1,727 cal | −1,750 cal |
| Lose 1 lb/week | −500 cal | 1,477 cal | −3,500 cal |
| Gain 0.5 lb/week | +250 cal | 2,227 cal | +1,750 cal |
The pacing table also shows why aggressive goals stop making sense for smaller or less active people. A 2 lb/week pace would put this example at 1,977 − 1,000 = 977 calories a day, well below the roughly 1,200-calorie floor generally advised for women (about 1,500 for men) without medical supervision. If a pace pushes your target under those floors, choose a slower pace instead, and involve a doctor or registered dietitian before attempting anything more restrictive. Gaining works the same way in reverse: a modest surplus of about 250 calories a day typically supports lean gain, while much larger surpluses tend to add more fat than muscle.
Frequently asked questions
How many calories should I eat to lose weight?
To lose weight you need to eat fewer calories than you burn. A common, sustainable starting point is a deficit of about 500 calories a day below your maintenance (TDEE) level, which targets roughly one pound of fat loss per week. Faster loss is possible with a larger deficit, but it's harder to sustain and risks losing muscle. This calculator does the math for you once you pick a loss goal — but treat the number as a starting estimate and adjust based on real results.
Is it safe to eat very few calories?
Eating too little can be risky. As a general guide, adult women shouldn't drop below about 1,200 calories a day and adult men below about 1,500 without medical supervision, because very-low-calorie diets can cause nutrient deficiencies, muscle loss and a slowed metabolism. If our calculator suggests a target below those floors for an aggressive goal, choose a gentler goal instead — and always consult a doctor or registered dietitian before starting a restrictive plan.
Why does a pound equal 3,500 calories?
The "3,500 calories per pound" figure is a long-standing estimate of the energy stored in a pound of body fat. It's why a daily deficit of 500 calories (500 × 7 = 3,500 per week) is often cited as roughly one pound of weekly loss. In practice it's an approximation — metabolism adapts as you lose weight, so real-world results vary. It's still a handy planning rule, just not an exact guarantee.
Should I eat the same calories every day?
You can, and consistency makes tracking easier, but you don't have to. What matters most for weight change is your average intake over the week relative to your TDEE. Some people prefer to eat a little more on training days and less on rest days. As long as the weekly total lands near your target, the day-to-day distribution is mostly a matter of personal preference and what keeps you consistent.
How accurate is this calorie target?
It's a solid estimate for most healthy adults, but not a precise prescription. It depends on the accuracy of your inputs — especially how honestly you rate your activity level — and on the Mifflin-St Jeor equation, which can't see your body composition or genetics. Use the target as a starting point, track your weight over two to three weeks, and adjust up or down by 100 to 200 calories if the scale isn't moving the way you expect. For personalized advice, see a healthcare professional.
Which activity level should I pick if I'm between two?
Pick the lower one. Most people overestimate how active they are, and a desk worker who trains three times a week usually lands closer to lightly active than moderately active. A conservative estimate is safer for a weight-loss target because it will not overstate how much you can eat. If you lose faster than planned after two or three weeks of honest tracking, move up one level and recalculate.
Do I need to eat back the calories I burn exercising?
Usually not. The activity multiplier already includes your typical exercise, so adding workout calories on top would count them twice. The exception is a one-off effort far beyond your normal week, such as a long hike or a race, where eating a few hundred extra calories that day is reasonable. Fitness trackers also tend to overstate calorie burn, so treat their numbers with caution.