Free nutrition tool
Use this calorie calculator to estimate your maintenance calories (TDEE), your BMR, and targets for getting lean or building muscle. Pick Mifflin-St Jeor, revised Harris-Benedict or Katch-McArdle, enter your stats and activity level, and you get a daily number plus cut and bulk ranges around it. Results are estimates; confirm them against the scale over three weeks.
The lean bulk calculator on this site uses the same maintenance maths, so the two never disagree.
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Maintenance calories, your BMR, and daily targets for getting lean or building muscle.
Use it well
The formula gives you a starting estimate. Three weeks of scale data turns that estimate into your actual maintenance number, and that is the one worth building a plan on.
Step 1
Your current bodyweight, your age, your height, and the activity level that matches a normal week rather than your best one. Picking an activity level one step too high is the most common reason a calorie target comes out wrong.
Step 2
Eat the maintenance number for two to three weeks and watch the weekly average on the scale. If it holds, the estimate was right and every target below is now built on a real number instead of a formula.
Step 3
Weight falling faster than the pace next to your target means eating a little more. Weight flat when you expected it to move means eating a little less. Two hundred calories is usually enough of a change.
The two numbers
BMR is what your body burns doing nothing at all: breathing, pumping blood, keeping you warm. It is roughly 60 to 70% of the day for most people, and it is the number the three formulas on this page estimate.
TDEE is BMR times your activity multiplier, and it is the number you eat to. Everything you do on top of lying still is in that multiplier: your steps, your job, your training, even digesting the food. That is why picking the activity level honestly matters more than picking the formula. Two steps up the activity list moves a 1,700 kcal BMR by about 600 kcal a day, which is far more than the gap between Mifflin-St Jeor and Harris-Benedict.
The full explainer on TDEE and BMR goes through where each part of the day fits.
Daily targets
The calculator prints maintenance and the tiers around it. Which tier you pick depends on how fast you want bodyweight to move and how much of your training you are willing to give up to get there.
Start with a modest calorie deficit that is easier to sustain, then adjust based on weekly scale trends, gym performance, and recovery.
Maintenance calories are the intake that keeps body weight roughly stable over time when average activity stays the same.
A smaller surplus is usually more productive for lean gains because it supports training and recovery without unnecessary fat gain.
One pound of fat is about 3,500 kcal, so a 500 kcal daily deficit works out near a pound a week on paper. Real weeks are messier than that, because water and food in the gut move the scale by more than the fat does. Judge a target on the weekly average over three weeks, not on any single morning.
Formula guide
Mifflin-St Jeor, unless you have a reliable body fat measurement. Frankenfield's 2005 review found it landed within 10% of measured resting metabolic rate more often than the alternatives, which is why it is the default here.
Best default choice for most adults. It is widely used for everyday calorie estimation and is the safest starting formula for general use.
Useful as a comparison estimate if you want a second calorie baseline. It is older, but still common in calculators and coaching tools.
Best when you know your body fat percentage with reasonable accuracy because it uses lean body mass and can fit leaner athletes well.
| Formula | What it uses | Pick it when |
|---|---|---|
| Mifflin-St Jeor | Weight, height, age, sex | Almost always |
| Revised Harris-Benedict | Weight, height, age, sex | You want a second estimate to compare |
| Katch-McArdle | Lean mass, from your body fat % | You have a DEXA or a caliper reading you trust |
Run the same stats through all three and the answers will usually sit within about 150 kcal of each other. That gap is smaller than the error in your food logging, so it is not the thing to agonise over. Pick one, eat it for three weeks, and let the scale settle the argument.
In the app
The nutrition journal in Ultra+ logs food by search or barcode scan and shows calories and macros against your target for the day. Set the target from this calculator, log what you eat, and the weekly average is there when it is time to decide whether the number needs moving. Workouts and bodyweight sit in the same app, so a stalled cut and a stalled bench press are on one screen.
FAQ
Short answers to the questions people bring to a TDEE or maintenance calorie search.
BMR is the calories your body uses at complete rest. TDEE starts with BMR, then adds your daily movement, exercise, and general activity to estimate full daily calorie burn. The calculator shows both, and the goal targets are built from TDEE.
It is an estimate, not a lab measurement. The formulas are useful starting points, but your real maintenance calories should be confirmed by tracking body weight, intake, and training performance for a few weeks and adjusting from there.
Mifflin-St Jeor is the best default for most adults. Katch-McArdle can be a strong option if you have a reliable body fat estimate and want a lean-mass-based calculation. Revised Harris-Benedict is there as a second opinion.
Recalculate after a meaningful body weight change, a big shift in activity level, or when progress stalls for multiple weeks despite good compliance. A 5 kg change in bodyweight is usually enough to move the number by a meal.
Usually no. More aggressive deficits can reduce recovery, increase hunger, and make training harder to sustain. Smaller adjustments are often easier to maintain and easier to refine, and they keep more of the muscle you built.
Not necessarily. The weekly total is what moves bodyweight. Many lifters eat a little more on training days and a little less on rest days, which puts carbs where the work is. Keep the weekly average on target and pick whichever pattern you will actually follow.
Keep going
Ultra+ logs your food with barcode scanning and puts the day's calories next to your training and your bodyweight, so you can see whether the number you set is doing what you wanted.
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