TDEE Calculator

What is a TDEE calculator?

A TDEE calculator estimates how many calories your body burns in a typical day. TDEE stands for total daily energy expenditure — the full amount of energy you use across resting, moving, exercising and digesting food. It's the single most useful number for managing your weight, because eating below it leads to loss, eating above it leads to gain, and eating around it holds you steady.

The tool above builds your TDEE in two steps. First it calculates your BMR (basal metabolic rate) using the Mifflin-St Jeor equation — the energy you'd burn lying still all day. Then it multiplies that by an activity factor matched to how active you really are. It also shows the older Harris-Benedict estimate alongside for comparison, ready-made calorie targets for cutting, maintaining and bulking, and a suggested protein, fat and carbohydrate split.

Everything runs in your browser. Your age, weight and height are personal, so nothing you enter is uploaded — the estimate is calculated on your own device, instantly.

What BMR and TDEE actually mean

BMR is your body's idle cost. Even asleep, you spend energy keeping your heart beating, your lungs working, your brain running and your cells repairing themselves. For most adults, BMR is the largest single slice of daily energy use — often 60–70% of the total.

TDEE adds everything on top of that idle cost:

• Physical activity — both deliberate exercise and the incidental movement of daily life (walking, fidgeting, standing).
• The thermic effect of food — the energy spent digesting and processing what you eat, roughly 10% of intake.

Because activity varies enormously between people, you can't get TDEE from a formula alone. You estimate BMR precisely, then scale it by an activity multiplier — and that's exactly what this calculator does.

How to use it

1. Pick your units — metric (cm, kg) or imperial (ft·in, lb).
2. Choose your sex. The formula uses a different constant for males and females, reflecting average differences in lean mass.
3. Enter your age, height and weight. Use recent, honest measurements for the best estimate — if you're not sure of your exact age, the age calculator works it out from your birth date.
4. Select your activity level. Be realistic — most people overestimate. If you sit most of the day and train a few times a week, "lightly" or "moderately active" is usually closer than "very active".
5. Read your results. The headline is your TDEE; below it sit your two BMR estimates, calorie targets for each goal, and a macro suggestion. Use Copy to save the summary.

The Mifflin-St Jeor formula

The Mifflin-St Jeor equation estimates BMR in calories per day:

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

Published in 1990, it's now the formula most dietitians reach for because it tracks measured metabolic rates more closely than older equations for the average modern adult. The calculator also runs the revised Harris-Benedict equation so you can see a second opinion — the two usually land within a hundred calories or so of each other.

Once BMR is known, TDEE is simply:

TDEE = BMR × activity factor

Activity multipliers explained

The activity factor scales your resting burn up to your real-world burn. The standard multipliers are:

• Sedentary (×1.2) — desk job, little or no exercise.
• Lightly active (×1.375) — light exercise 1–3 days a week.
• Moderately active (×1.55) — moderate exercise 3–5 days a week.
• Very active (×1.725) — hard exercise 6–7 days a week.
• Extra active (×1.9) — very hard training or a physically demanding job.

Choosing the right band is where most estimates go wrong. The gap between sedentary and very active can be hundreds of calories, so an over-optimistic pick inflates your TDEE and quietly stalls a diet. When in doubt, choose the lower band and let real results guide you up.

A worked example

Take a 30-year-old man, 178 cm, 75 kg, moderately active.

• BMR (Mifflin-St Jeor): 10·75 + 6.25·178 − 5·30 + 5 = 750 + 1,112.5 − 150 + 5 = 1,717.5 kcal
• TDEE: 1,717.5 × 1.55 ≈ 2,662 kcal/day

So he burns roughly 2,660 calories on a typical day. To lose weight at a steady pace he'd aim near 2,160 (a 500-calorie deficit); to gain he'd target around 3,160. The calculator fills in all five targets — aggressive cut, mild cut, maintain, lean bulk and bulk — automatically for your own figures.

Using TDEE for cutting and bulking

TDEE is the pivot point. Eat below it and your body makes up the shortfall from stored energy (a cut); eat above it and it has surplus to build with (a bulk); eat at it to maintain.

• Cutting. A deficit of 250–500 calories a day is sustainable and protects muscle. A pound of fat holds about 3,500 calories, so a 500-a-day deficit averages roughly a pound of loss per week. Bigger deficits work faster but get harder to stick to and risk losing muscle.
• Bulking. A surplus of 250–500 supports muscle growth without piling on excess fat. "Lean bulk" (the smaller surplus) is the slower, cleaner route; the larger surplus gains faster but fattier.
• Maintaining. Eating at TDEE holds your weight. It's also the right starting point if you simply want to learn your numbers before choosing a direction.

The crucial caveat: these are estimates. Your true expenditure reveals itself over time. Pick a target, hold it for two to three weeks, track your weight trend, and adjust by 100–200 calories based on what actually happens — not on what the formula predicted.

Macro basics

Calories decide whether you lose or gain weight; macros (protein, fat and carbohydrate) shape how you feel, perform and recover, and how much of any change is muscle versus fat.

• Protein is the priority, especially when cutting — it preserves muscle and keeps you full. A common target is around 1.6–2.2 g per kg of body weight.
• Fat supports hormones and absorption; roughly 20–30% of calories is a sensible range.
• Carbohydrate fills the rest and fuels training and brain function.

The calculator's suggested split uses 2 g of protein per kg, 25% of calories from fat, and the remainder from carbs — a solid default you can tune to your tastes and training.

Caveats — this is an estimate

A formula can't measure your metabolism; it predicts the average for someone with your stats. Real BMR varies with muscle mass, genetics, hormones, sleep, stress and medical conditions, and can sit a few hundred calories either side of the estimate. The activity multiplier adds more uncertainty still.

So use this as a starting line, not a verdict. Track your intake and weight for a couple of weeks, compare what really happened, and adjust. And for any medical condition, pregnancy, eating disorder history, or a serious performance goal, work with a doctor or a registered dietitian — a calculator is a helpful first step, not a substitute for professional advice.

Private, instant and always free

This TDEE calculator runs entirely in your browser. There are no accounts, no limits, and your personal figures never leave your device. Keep it handy whenever you're setting or revisiting a nutrition plan — it turns a few measurements into a clear calorie target and a sensible macro split in seconds, while your numbers stay yours. For a quick complementary read on where your weight sits, pair it with the BMI calculator.