Calorie Calculator: Your Daily Needs

How many calories do you actually need?

Every plan — losing weight, maintaining it, or building strength — starts with the same question: how much energy does your body burn in a day? That number is your Total Daily Energy Expenditure (TDEE), and once you know it, the guesswork disappears. Eat near it and your weight holds steady; eat consistently below it and you lose; eat above it and you gain.

Your TDEE has two parts. The first is your basal metabolic rate (BMR) — the energy your body uses just to keep you alive: breathing, circulating blood, maintaining body temperature. The second is everything you do on top of that, from walking to the shops to an hour at the gym. This calculator estimates both using the Mifflin-St Jeor equation, the formula dietitians trust most.

Enter your age, height, weight, and activity level below, and you will get your BMR, your TDEE, and suggested daily targets for maintaining, losing, or gaining weight — in seconds.

Activity level multipliers

The calculator multiplies your BMR by one of these activity factors to estimate your TDEE. Be honest about your typical week — most people overestimate.

Activity level Multiplier What it looks like
Sedentary × 1.2 Desk job, little or no exercise — most of the day sitting.
Lightly active × 1.375 Light exercise or daily walks, 1–3 days a week.
Moderately active × 1.55 Moderate exercise 3–5 days a week — brisk walking, swimming, cycling.
Very active × 1.725 Hard exercise 6–7 days a week, or a physical job plus training.
Extremely active × 1.9 Twice-daily training or heavy manual labour.

Eating for your goal

To maintain: eat at your TDEE. Your weight stays roughly stable, which is itself a worthy goal — especially after 50, when holding steady beats yo-yo dieting every time.

To lose weight: aim for about 300–500 calories below your TDEE per day. That pace — roughly half a kilo a week — is the fastest rate most dietitians consider sustainable, because it preserves muscle and keeps hunger manageable. Crash deficits backfire: they cost you muscle, slow your metabolism, and the weight comes back.

To gain weight or build muscle: eat about 200–300 calories above your TDEE, with plenty of protein and strength training two to three times a week. After menopause this matters more than ever, since muscle protects your bones, balance, and independence.

Why this is an estimate, not a lab result

No formula can measure your actual metabolism — that takes a lab. The Mifflin-St Jeor equation is accurate within about 10% for most people, which is excellent for planning but means your true number could sit a couple of hundred calories either side. Hormones, medications, muscle mass, and even room temperature all nudge the real figure.

Treat the calculator’s number as your starting hypothesis. Follow it for two to three weeks, watch the scale and the tape measure, then adjust: if nothing is moving, shift your target by 100–200 calories and watch again. Your body’s response is the final authority, not the formula.

This calculator is for general information only and is not medical advice. If you have a medical condition, are pregnant, or have a history of disordered eating, please speak to your doctor or a registered dietitian.

Frequently asked questions

Why do I need fewer calories after 50?
Metabolism naturally slows with age — roughly 1–2% per decade after 40 — mostly because muscle mass declines and hormone shifts change how the body stores energy. The drop is real but modest, and it is largely offset by staying active and keeping muscle through strength training. The calculator already accounts for your age.
Should I eat back the calories I burn exercising?
Your TDEE already includes your activity level, so in most cases: no extra eating needed. The exception is a big training day well above your usual routine — then a modest refuel with protein and carbs helps recovery. Fitness trackers notoriously overestimate burn, so treat their numbers with suspicion.
Is 1,200 calories a day safe?
For most women it is too low unless a doctor has specifically advised it. Very low intakes risk muscle loss, nutrient deficiencies, hair thinning, and hormonal disruption — and they are almost impossible to sustain. A moderate deficit from your own TDEE works better and lasts longer.
Do I need to count calories forever?
No. Counting for a few weeks teaches you what portions actually contain — most people are surprised — and then you can ease off. Many women do well shifting to simple habits instead: protein at every meal, vegetables filling half the plate, and mindful portions of everything else.
Why am I not losing weight at a calorie deficit?
The usual suspects: underestimating portions (oils, dressings, and snacks are the classic culprits), overestimating activity, water retention masking fat loss on the scale, or not giving it enough time. Track honestly for two full weeks, measure your waist as well as your weight, and adjust from real data.
Does menopause change how many calories I need?
It can lower needs slightly — declining oestrogen is linked to a small drop in resting metabolism and a shift toward storing fat around the middle. But the bigger factor is activity: women who keep moving and lift weights through menopause largely hold their calorie needs steady. Strength training is the single best countermeasure.