TDEE Calculator

Written by the CalculatorBoss Health Team · Formulas verified against a reference implementation with a recorded test suite · Last updated August 2026

What TDEE is made of

Total daily energy expenditure is everything your body spends in twenty-four hours. It breaks into three parts, and they are wildly unequal.

Basal metabolic rate is the largest, usually 60 to 70% of the total — the cost of keeping your heart, brain, liver and kidneys running while you do nothing. Activity is roughly 20%, and it covers far more than deliberate exercise: walking to the bus, standing, fidgeting and everything else physiologists group under non-exercise activity thermogenesis. The thermic effect of food is the remaining 10% or so, the energy spent digesting and absorbing what you eat. Protein costs noticeably more to process than fat, which is why the figure shifts a little with diet composition.

Put plainly: the majority of the bill is already settled before you decide anything, and the portion genuinely under your control on a given day is the minority of it. That is not an argument against exercise; it is an argument against expecting a single workout to move the total much.

How this calculator works

Two steps. First it estimates BMR from your body, then it multiplies by an activity factor.

Run the page defaults through it — a 34-year-old man of 5′9″ and 178 lb who trains four or five times a week. His BMR lands near 1,738 Calories under Mifflin St Jeor, and the moderate multiplier of 1.465 lifts that to a TDEE of 2,546 Calories a day.

The intake tables then step away from that figure in fixed amounts. A pound a week is treated as 500 Calories a day, half a pound as 250, two pounds as 1,000; in metric the steps are a quarter, a half and a full kilo a week. The percentage beside each row shows what that target is as a share of maintenance, which is a more useful way to judge how aggressive a deficit is than the raw number.

Choosing Basal Metabolic Rate from the activity list is a special case: it returns BMR on its own, with no intake targets, because that figure is not something to eat at.

Choosing an activity level honestly

This is where the estimate is won or lost. On the default figures, sedentary gives 2,085 Calories and extra active gives 3,302 — a spread of over 1,200 Calories a day for the same person. No refinement of the BMR equation matters next to picking the wrong band.

• Sedentary (1.2) — desk job, little deliberate exercise, not much walking.
• Light (1.375) — one to three sessions a week, otherwise mostly seated.
• Moderate (1.465) — four or five sessions a week. This describes a lot of people who think they are more active than this.
• Active (1.55) — daily exercise, or hard training three or four times a week.
• Very active (1.725) — intense training six or seven times a week.
• Extra active (1.9) — twice-daily training, or manual work all day on top of exercise.

Training intensity is easier to judge with a number attached. Our target heart rate calculator gives your zones from age and resting pulse, and runners can set a realistic session with the pace calculator.

The common error runs in one direction. If your job is seated, start one band lower than instinct suggests and let a few weeks of weight data correct you upward if it is wrong. It is easier to notice you have set the target too low than to work out why a supposed deficit is not producing anything.

Reading the intake tables

The lose and gain rows are arithmetic, not advice. Roughly 3,500 Calories corresponds to a pound of body weight, so a 500-a-day deficit lines up with about a pound a week. Real bodies do not follow that as cleanly — water shifts mask the trend for days at a time, and expenditure itself drifts — but as a planning figure it holds up.

Two guardrails are built in, both matching what the reference tool does. Any target that would fall below about 1,500 Calories a day is withheld, with a note, because sustained intake at that level is a medical conversation rather than a self-service one. And if your BMI is already below the healthy range, the weight-loss section does not appear at all.

The percentages are worth more attention than the absolute numbers. A deficit at 90% of maintenance is gentle and generally sustainable; one at 60% is aggressive and much harder to hold without losing lean mass alongside fat. If you want to keep muscle while the fat comes off, the shallower rows plus resistance training do that far better than the steepest row does.

Why the number moves, and what to do about it

TDEE is not a constant. It falls as you lose weight, because there is less body to run — which is the ordinary mechanism behind a stall that seems to arrive from nowhere. Extended dieting drags it lower again, past what the shrinking body by itself would explain, as the system quietly economises. It also moves with the seasons, with sleep, with illness and with how much you unconsciously fidget.

So treat the output as a starting hypothesis and let your own data correct it. Hold roughly to a target for two to three weeks, weigh yourself consistently, and compare the trend to what the calculator predicted. If your weight is flat on a supposed 500-a-day deficit, the activity level is the first thing to revisit, and intake tracking the second. Recalculate every ten to fifteen pounds of change rather than once at the start.

What this calculator does not cover

• What to eat. A daily total says nothing about how to divide it between protein, carbohydrate and fat, and that split matters for whether a deficit costs you muscle. The macro calculator picks that up.
• Anyone outside 18 to 80. The underlying research covers working-age adults. Rather than extend a curve past its data, the tool simply refuses those ages.
• Pregnancy and nursing. Requirements rise sharply and follow their own trajectory, which nothing on this page attempts to represent.
• Illness and prescriptions. An under- or over-active thyroid can shift daily expenditure by hundreds of Calories, and a long list of everyday prescriptions nudge it one way or the other.
• Bodies at the extremes. Competitive physiques and very high body fat both sit where population averages fit worst. A measured body fat reading with Katch-McArdle narrows the gap; nothing closes it.
• Anyone with a difficult history around food. A number that frames eating as a target to hit can be actively harmful, and no calculator can judge whether that applies to you. Bring this to a clinician instead.

For the pieces either side of this one, the BMR calculator shows the resting figure on its own and the calorie calculator approaches intake from a different angle.

Frequently asked questions

What is TDEE and how is it different from BMR?

BMR is what your body burns at complete rest. TDEE is everything you burn in a day: BMR plus movement, exercise and the energy used to digest food. TDEE is the larger number and the one that matters for eating, because it is what you have to match to hold your weight steady. The calculator works out BMR first and multiplies it by an activity factor to reach TDEE.

How many calories should I eat to lose weight?

The intake table shows the arithmetic: roughly 500 Calories a day below TDEE tends to produce about a pound a week, and 250 below produces about half that. Those are starting estimates, not prescriptions. Nothing below about 1,500 Calories a day is shown, because going lower is something to plan with a doctor or dietitian rather than from a web page.

Which activity level should I choose?

Pick the one that describes your whole week, not your best day. Three or four gym sessions alongside a desk job is light to moderate; "very active" means daily hard training or a physically demanding job. This is the single largest source of error in the calculation — the gap between sedentary and extra active is over 1,200 Calories a day on the same body — and most people pick too high.

How accurate is a TDEE estimate?

It is a starting point with real uncertainty. The BMR equation underneath carries roughly 10% error for most people, and the activity multiplier is a coarse step rather than a measurement. Treat the figure as a hypothesis: eat close to it for two or three weeks, track your weight, and adjust based on what actually happens rather than on what the equation predicted.

Why is my weight not changing even though I eat my TDEE?

That is the calculator working as intended — eating at TDEE is meant to hold your weight steady. If you wanted a change, use the lose or gain rows instead. If you are eating a deficit and nothing is moving after a few weeks, the usual explanations are that intake is being under-recorded, the activity level was set too high, or the deficit is small enough to be hidden by normal water-weight variation.

Should I use Mifflin St Jeor or Katch-McArdle?

Mifflin St Jeor unless you have a reliable body fat measurement. It is the more accurate of the two for the general population and needs nothing you cannot measure at home. Katch-McArdle works from lean mass and has the edge on very lean or heavily built physiques — but only where the body fat figure is good, since a guess feeds straight into the answer.

Does TDEE change as I lose weight?

Yes, and this is why plateaus happen. A smaller body costs less to run, so TDEE falls as you lose, and a deficit that worked at the start becomes maintenance later on. Recalculate every 10 to 15 pounds or so. Long stretches of dieting also push expenditure down further than the lighter body by itself would explain.

Why does the calculator show my BMI too?

As context for the intake numbers rather than as a second verdict. Below a healthy BMI the calculator stops offering weight-loss targets entirely. BMI takes no account of build, so a muscular person can read as overweight while carrying very little fat — which is exactly the case where the body fat calculator and Katch-McArdle tell you more.

Everything here is an educational estimate. It carries no clinical weight, replaces no consultation, and diagnoses nothing — and a predicted figure can sit a long way from what a metabolic cart would actually measure on you. The intake rows in particular are arithmetic, not a plan: before adopting any of them as a daily target, talk to a physician or a registered dietitian. That applies with real force during pregnancy or nursing, below the age of 18, alongside any diagnosed condition or medication that touches metabolism, and for anyone who has struggled with food in the past. Learn more about how we build these tools or read our privacy policy.