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How Many Calories Should I Eat a Day? A Simple Framework

There is no single right answer to this question, which is exactly why the generic charts fail you. Your daily calorie target depends on two things and two things only: how much energy you burn in a day, and what you want your body to do. Get those two inputs right and the number falls out almost automatically. Here's the framework.

It comes down to two things

Strip away the noise and your daily calorie number is a simple function of two inputs. The first is your TDEE (Total Daily Energy Expenditure) — the total calories your body burns in 24 hours. The second is your goal — whether you want to lose fat, hold steady, or build muscle. Everything else is detail.

Once you know your TDEE, every goal is just a shift up or down from that anchor. Eat below it and you lose weight. Eat at it and you maintain. Eat above it and you gain. That's the entire model. The rest of this guide is about pinning down the two numbers accurately.

Step 1: estimate your TDEE

TDEE starts with your BMR (Basal Metabolic Rate), the calories you'd burn lying in bed all day. The most reliable formula for the general population is Mifflin-St Jeor:

Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Then you multiply BMR by an activity factor to account for how much you move on top of just being alive:

TDEE = BMR × activity multiplier
Activity levelMultiplierLooks like
Sedentary1.2Desk job, little to no exercise
Light1.375Office work + 1–3 workouts per week
Moderate1.55Trains 3–5x per week, on feet often
Heavy1.725Manual job + near-daily training
Athlete1.9Two-a-days, competitive training load

Be honest here. The single most common error is picking "Moderate" when your week is really one of office sitting plus two gym sessions. That's Light. Overstating activity inflates your target by 300–500 calories and quietly stalls progress before you even begin.

Skip the arithmetic

The calculator runs Mifflin-St Jeor and the activity multiplier together and hands you a TDEE.

Calculate My TDEE →

Step 2: adjust for your goal

With TDEE in hand, the goal adjustment is straightforward. A deficit of 250–500 calories per day produces steady, sustainable fat loss without gutting your energy or muscle. A surplus of 250–500 supports lean gains while keeping fat accumulation modest. Maintenance is simply TDEE itself.

GoalAdjustmentRoughly equals
Fat loss (cut)TDEE − 250 to 5000.5–1 lb lost per week
MaintenanceTDEE (no change)Weight holds flat
Muscle gain (bulk)TDEE + 250 to 5000.25–0.5 lb gained per week
The rule: Your goal is always expressed as a shift from TDEE, never as a fixed number you read off a chart. Find TDEE first, then apply the adjustment. If you only remember one thing, remember that order.

Worked examples

Numbers make this concrete. Consider two people with realistic stats.

Sample man: 35 years old, 185 lb (84 kg), 5'11" (180 cm), trains 3–4 times per week. His BMR works out to about 1,800 calories. At a Moderate multiplier of 1.55, his TDEE is 1,800 × 1.55 ≈ 2,790. To cut, he'd eat around 2,300–2,500. To bulk, around 3,000–3,300.

Sample woman: 30 years old, 150 lb (68 kg), 5'5" (165 cm), works a desk job with two weekly gym sessions. Her BMR is about 1,400 calories. At a Light multiplier of 1.375, her TDEE is 1,400 × 1.375 ≈ 1,925. To cut, she'd eat around 1,500–1,650. To maintain, about 1,900.

ProfileTDEECutMaintainBulk
Man, 185 lb, moderate~2,7902,290–2,5402,7903,040–3,290
Woman, 150 lb, light~1,9251,425–1,6751,9252,175–2,425

Why generic numbers fail

You've seen "women eat 2,000, men eat 2,500" everywhere. Those figures come from population-average reference values printed on food labels, not from your body. A 5'1" sedentary woman and a 5'10" athletic woman can differ by 800 calories at maintenance. Handing them the same 2,000 guarantees one is overeating and the other is starving.

The same goes for the famous "1,200-calorie diet." That figure is a marketing convention, not a prescription. For many women it sits well below their BMR, which makes it both miserable and counterproductive over time. Your number is yours. The whole point of the framework is to stop borrowing someone else's.

Minimum intake floors

A deficit works, but you can take it too far. Eating far below your BMR for extended periods drives muscle loss, hormonal disruption, persistent fatigue, and the adaptive slowdown that causes plateaus. As rough lower bounds for self-directed dieting, most guidance puts the floor around 1,200 calories for women and 1,500 for men — and, more importantly, you should not park below your BMR long-term.

The floor rule: Treat ~1,200 (women) and ~1,500 (men) as soft minimums, and never sit below your BMR for weeks on end. If your goal math pushes you under that line, shrink the deficit and lose more slowly instead.

Verify and adjust

Every formula is an estimate within roughly ±10%, so treat your starting number as a hypothesis, not a verdict. The fix is simple: eat your target consistently for two weeks while logging your weight first thing each morning, then average each week. Body weight is noisy day to day because of water, food in transit, and sodium, which is why you average rather than react to single readings.

FAQ

Is 1,200 calories enough?

For many shorter or sedentary women it can be a valid floor for short cutting phases, but for most people it's too low to sustain and frequently dips below BMR. It is rarely the right answer for men. Calculate your actual TDEE first; if a sensible deficit still lands you near 1,200, lose weight more slowly rather than going lower.

Should men and women eat differently?

Not because of sex itself, but because the inputs differ. Men tend to be taller, heavier, and carry more muscle, which raises BMR and therefore TDEE. The Mifflin-St Jeor formula already bakes that in. Use the same framework for both; the numbers it produces simply land in different places.

How do I know if my number is right?

The scale tells you over two weeks, not two days. If your weekly average is moving in the intended direction at a reasonable rate, your number is correct for now. If it's stuck after a clean fortnight of tracking, adjust by 100–150 calories and reassess.

Do I need to eat back exercise calories?

If you used an activity multiplier to set your TDEE, your training is already accounted for, so don't add calories back on top of it — that's double-counting. The exception is the calculator-free "track and add back" style some apps use; if you set a sedentary baseline and log workouts separately, eating back a portion makes sense. Pick one method and stick with it.

Get your number in 30 seconds

Enter your stats and goal, and the calculator returns your TDEE plus targets for every goal at once.

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