How many calories should I eat to lose weight?

A common starting point is around 20 percent below your TDEE, which for most people produces a loss of roughly 0.5 to 1 percent of bodyweight per week. Larger deficits work faster but are harder to sustain and carry more muscle-loss risk. This is general information, not personalised dietary advice — if you have a health condition, speak to a doctor or dietitian.

What is the difference between BMR and TDEE?

BMR is what your body burns at complete rest, just keeping you alive. TDEE is BMR multiplied by an activity factor, so it includes digestion, exercise and everyday movement. TDEE is always the larger number and it is the one to base your intake on.

Is Mifflin-St Jeor or Harris-Benedict more accurate?

Mifflin-St Jeor. It was developed in 1990 specifically because the 1919 Harris-Benedict equation was found to overestimate for modern populations, and it has consistently outperformed it in comparison studies. Harris-Benedict is shown here only for reference.

Should I eat back the calories I burn exercising?

Not if you selected an activity level that already accounts for your training — that would double-count it. The activity multiplier in this calculator is designed to include your usual exercise, so eat at the resulting TDEE rather than adding your workout burn on top.

Why is my weight not changing at my calculated TDEE?

Because the estimate is off for you, which is completely normal. Predictive equations carry roughly a ten percent margin, and activity level is self-reported. Eat consistently at the number for two to three weeks, watch the two-week average of your weight, and adjust by 200 to 300 calories in whichever direction you need.

Nutrition

TDEE calculator

Your TDEE — total daily energy expenditure — is roughly how many calories you burn in a day, including training. This calculator works it out using three published equations side by side, so you can see how much they disagree, and gives you cutting and lean-bulk targets from the result.

Free, no signup. Everything is calculated in your browser — nothing you enter is uploaded.

How this is calculated

Mifflin-St Jeor (1990) — the default

Men: 10w + 6.25h − 5a + 5 · Women: 10w + 6.25h − 5a − 161  (w in kg, h in cm, a in years)

Generally the most accurate predictive equation for the general population, and the one most dietetic guidance defaults to.

Katch-McArdle — used automatically if you enter body fat %

BMR = 370 + 21.6 × lean body mass (kg)

Works from lean mass rather than total mass, so it is more accurate for lean and muscular people, whose bodyweight alone misrepresents their metabolic tissue. It ignores sex entirely, because lean mass already accounts for the difference.

Harris-Benedict (Roza & Shizgal 1984 revision) — shown for comparison

Men: 88.362 + 13.397w + 4.799h − 5.677a · Women: 447.593 + 9.247w + 3.098h − 4.330a

The original equation dates to 1919 and tends to read slightly high. Included so you can see the spread rather than trusting a single number.

Activity multiplier

TDEE = BMR × 1.2 to 1.9

1.2 sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, 1.9 extremely active. This is the least precise part of the whole calculation and the place most people overestimate.

What your result means

Goal	Adjustment	Expected rate
Fat loss	−20% from TDEE	Roughly 0.5–1% of bodyweight per week
Maintenance	TDEE	Weight stable over a two-week average
Lean gain	+10% over TDEE	Roughly 0.25–0.5% of bodyweight per week
Aggressive cut	−25% or more	Faster, with more muscle loss risk and worse adherence

Judge these against a two-week average of your bodyweight, not day-to-day readings — daily fluctuation from water and food volume is far larger than daily fat change.

What is TDEE?

TDEE is your total daily energy expenditure: everything your body burns in twenty-four hours. It has four components — your basal metabolic rate, the energy used digesting food, deliberate exercise, and all the incidental movement you do without thinking about it.

Basal metabolic rate is the largest share, typically around 60 to 70 percent for most people. Deliberate exercise is usually a smaller contributor than people expect, which is why calculators ask about your general activity level rather than just your training.

Basal metabolic rate (BMR) — energy used at complete rest. The biggest component.
Thermic effect of food — energy used digesting and absorbing. Around 10% of intake.
Exercise activity — deliberate training sessions.
Non-exercise activity (NEAT) — walking, fidgeting, standing. Varies enormously between people.

How accurate is a TDEE calculator?

Treat the result as a starting estimate with a margin of roughly ten percent either way. Predictive equations estimate BMR from population averages, and individual metabolic rate varies around that average. The activity multiplier adds further imprecision, because self-reported activity is notoriously unreliable.

The practical approach is to use the number as a starting point, eat at it consistently for two to three weeks, and track your average bodyweight. If your weight is stable, that was your maintenance. If it is moving, adjust by a couple of hundred calories. Your own data beats any equation within a month.

Which formula should you use?

Use Mifflin-St Jeor unless you know your body fat percentage, in which case use Katch-McArdle. Mifflin-St Jeor is the most accurate general-population equation; Katch-McArdle works from lean mass and is better for people who are notably lean or notably muscular, where total bodyweight misrepresents how much metabolically active tissue they carry.

Harris-Benedict is shown here mainly for comparison. It is the oldest of the three and tends to read a little high, but seeing all three together makes the point that these are estimates with real spread, not precise measurements.

Why do people overestimate their activity level?

Because a training session feels like a bigger contribution than it is. An hour of hard lifting might account for 300 to 500 calories, which is a meaningful amount but far less than the jump between two activity multipliers on a typical BMR.

The multipliers are also intended to describe your whole life, not just your gym time. Someone who trains five times a week but otherwise sits at a desk and drives everywhere is closer to 'moderately active' than 'very active'. If you are unsure, pick one level lower and adjust based on what the scale does.

Frequently asked questions

How many calories should I eat to lose weight?: A common starting point is around 20 percent below your TDEE, which for most people produces a loss of roughly 0.5 to 1 percent of bodyweight per week. Larger deficits work faster but are harder to sustain and carry more muscle-loss risk. This is general information, not personalised dietary advice — if you have a health condition, speak to a doctor or dietitian.
What is the difference between BMR and TDEE?: BMR is what your body burns at complete rest, just keeping you alive. TDEE is BMR multiplied by an activity factor, so it includes digestion, exercise and everyday movement. TDEE is always the larger number and it is the one to base your intake on.
Is Mifflin-St Jeor or Harris-Benedict more accurate?: Mifflin-St Jeor. It was developed in 1990 specifically because the 1919 Harris-Benedict equation was found to overestimate for modern populations, and it has consistently outperformed it in comparison studies. Harris-Benedict is shown here only for reference.
Should I eat back the calories I burn exercising?: Not if you selected an activity level that already accounts for your training — that would double-count it. The activity multiplier in this calculator is designed to include your usual exercise, so eat at the resulting TDEE rather than adding your workout burn on top.
Why is my weight not changing at my calculated TDEE?: Because the estimate is off for you, which is completely normal. Predictive equations carry roughly a ten percent margin, and activity level is self-reported. Eat consistently at the number for two to three weeks, watch the two-week average of your weight, and adjust by 200 to 300 calories in whichever direction you need.

Workout split generator

A full week of training built around your days, goal and equipment — with a muscle coverage map.

One-rep max calculator

Estimate your 1RM from any set, see all four formulas, and check it against strength standards.

Barbell plate calculator

Which plates per side for any weight, in kg or lb, with an automatic warm-up ramp.

Sources

This tool provides general information about exercise and nutrition. It is not medical advice and not a substitute for a qualified professional. If you have a health condition, are pregnant, or are recovering from injury, speak to a doctor or registered dietitian before acting on any of these numbers.