TDEE Calculator: the calorie number that actually matters.

What this calculator does (and what it doesn't)

Your TDEE — Total Daily Energy Expenditure — is the total number of calories your body burns in a day. It's the most important number for almost any nutrition goal, because it tells you the line between losing weight, maintaining, and gaining. Eat below your TDEE consistently and you lose fat. Eat above it and you gain weight (a mix of muscle and fat, depending on training). Eat exactly at it and your weight stabilizes.

This calculator estimates TDEE from four inputs: your age, sex, height, and weight (for BMR), plus an activity multiplier that scales BMR up to account for everything else you do in a day. Underneath, it's using the Mifflin-St Jeor equation — the formula most heavily endorsed by the American Dietetic Association for the general adult population. If you enter your body fat percentage, the calculator switches to Katch-McArdle, which calculates BMR from lean body mass and is usually more accurate for lean, muscular bodies.

What this calculator does not do is read your mind. It can't see how much you actually walk, how restless your body is at rest, how much muscle you carry above the genetic average, or how many almonds you ate while making lunch. So treat the output as a strong starting estimate, then verify against the only honest scoreboard: your weight trend over 2–3 weeks. If the trend doesn't match, adjust by ~100 kcal and re-check.

How to use the result on a real-life day

Once you have your TDEE number, the play is simple: pick a goal, eat in the direction of that goal, and stay consistent enough that you can read the signal. Here's how to think about the three common goals.

Fat loss / cutting

Eat 15–25% below TDEE. A 20% deficit is the standard, sustainable cut for most people; 25% is aggressive and usually only worth it if you're short on time and high on willpower. A common mistake is going harder than 25% — the math says you'll lose faster, but the practical reality is that adherence collapses, NEAT drops (you fidget less, walk less, get tired), and the cut stalls. A moderate cut you actually stick to beats an aggressive cut you abandon.

Maintenance

Eat at TDEE ± 100 kcal. This is the underrated mode. After a long cut, spending 4–8 weeks at maintenance lets your hormones recover, blunts metabolic adaptation, and resets your appetite. Most people skip this phase, yo-yo back to old habits, and undo their progress. If you cut, you should also know how to maintain — and that requires actually doing it for a while.

Muscle gain / lean bulking

Eat 5–15% above TDEE, with protein dialed in (1.6–2.2 g per kg of body weight). The trade-off is honest: a bigger surplus means faster gain, but also more fat. A 10% lean bulk gains roughly 0.25–0.5 lb per week, which is about the natural rate of muscle accrual for an intermediate lifter. Anything faster is usually extra fat.

Common reasons your TDEE estimate feels wrong

People send me messages all the time saying “my TDEE says X but I'm eating Y and not losing weight, the calculator must be broken.” The calculator is almost never the issue. Here's what's usually happening:

• Untracked intake. The single most common one. Bites while cooking, condiments, oils used to sauté, weekend drinks, the second handful of nuts. Studies in self-reporters consistently show 20–40% underreporting. Track everything you put in your mouth for a single honest week and see what the actual number looks like.
• Activity multiplier set too high. “I work out 4 times a week” doesn't make you “Very active.” If the rest of your day is sitting at a desk and watching shows, you're probably “Lightly active” (×1.375). Drop a tier.
• Above-average lean mass. If you've lifted for years and carry more muscle than average for your size, Mifflin-St Jeor will underestimate you. Enter body fat percentage to switch the calculator to Katch-McArdle.
• Metabolic adaptation. If you've been cutting for months, your TDEE has drifted down 5–15% from where the formula says it should be. Take a 1–2 week diet break at maintenance and recalculate.
• Water and timing. A 2–3 lb weekly swing from water, hormones, or sodium is normal. Look at trends over 2 weeks, not single weigh-ins.

How to verify your TDEE against your own body

The single best thing you can do with this calculator is treat its output as Hypothesis Day 1, not a verdict. Here's the protocol I've used for myself, with my partner, and with two friends I've helped through their first deliberate fat-loss phase:

1. Calculate TDEE and pick your goal target.
2. Eat at that target for 14 days, weighing every day in the same conditions (morning, after bathroom, before food).
3. Average days 1–7 and days 8–14. The trend between those two averages is your real signal.
4. If the trend matches the goal (e.g., −0.5–1 lb/week for a moderate cut), keep going.
5. If the trend is flatter than expected, drop calories by ~100 kcal and re-check for another 2 weeks.
6. If the trend is steeper than expected and you feel under-fueled, add ~100 kcal back.

Two weeks isn't long enough to know if your shoes look better in jeans, but it's long enough to know if the math is matching the body. After three of these cycles, you'll know your real maintenance number to within ~50 kcal — which is more accurate than any calculator will ever give you.

What about the formula choice — Mifflin vs Katch vs Harris-Benedict?

You'll see TDEE calculators offer different equations and it's worth understanding what changes. Mifflin-St Jeor is from 1990 and is the modern consensus formula — it sits within ±10% of indirect calorimetry (the gold standard) for most healthy adults. Harris-Benedict is from 1919 (yes, that long ago) and tends to overestimate BMR by 5–15% on modern bodies. Katch-McArdle ignores age/sex entirely and uses lean body mass, which makes it accurate for athletic builds but completely dependent on accurate body fat measurement.

Practical rules: if you have a reliable body fat number from a DEXA, BodPod, or even a careful caliper measurement, use Katch. If not, use Mifflin. Don't use Harris-Benedict in 2026 unless you have a specific reason to.

Macros: protein first, then fat, then carbs fill the rest

Calories are the master variable for body weight, but macros decide what that weight is made of and how good you feel while changing it. The most important macro by a wide margin is protein. Protein is satiating, supports muscle retention during a cut, costs more energy to digest than fat or carbs, and is hard to overeat. Set protein to 1.6–2.2 g per kg of body weight (the higher end if cutting hard or training a lot), and you've solved 80% of the macro problem.

Fat is the next anchor — keep it above 0.5 g per kg to support hormones, typically landing in the 20–30% of total calories range. Below that floor for extended periods, hormones (especially testosterone in men, menstrual cycle regularity in women) start to suffer. Carbohydrates fill whatever calories are left, and they're the macro most flexible to your training preferences: heavier training days benefit from more carbs, rest days can swing lower.

Our calculator runs this math for you automatically — for cutting, maintenance, and bulking scenarios — so you don't have to.

About this calculator, and why I built it

Hi — I'm Sukie. I built this site because I've been calculating my own TDEE for the better part of a decade, mostly badly, occasionally well. I've watched two close friends — I'll call them L and R — go through their first deliberate fat-loss phases, and the thing both of them needed most wasn't a guru or a fancy app. It was a number, an honest explanation of what that number means, and someone to tell them that 1.7 lbs in week 1 is mostly water, that 0.3 lbs in week 3 is the real win, and that the scale isn't a moral judgement.

Most TDEE calculators on the internet are wrappers around the same equation with no soul attached — no context for what the number means, no acknowledgement that it's an estimate, no help with what to do next. I wanted a calmer page. The math here is identical to what every honest peer-reviewed source uses. The difference is what surrounds it.