Calorie & TDEE Calculator
Your maintenance calories and a target for losing, holding or gaining — with an honest margin of error attached.
Runs entirely in your browser. Nothing you type here is uploaded, stored or logged.
Where the number comes from
Two steps. First, BMR — what your body burns at complete rest, keeping your organs running. This tool uses the Mifflin-St Jeor equation, which has held up best in validation studies:
Men: BMR = 10×kg + 6.25×cm − 5×age + 5
Women: BMR = 10×kg + 6.25×cm − 5×age − 161Then BMR is multiplied by an activity factor to give TDEE. That factor covers deliberate exercise, incidental movement, and the energy used digesting food — which is itself about 10% of intake.
The activity multiplier is where estimates go wrong
BMR prediction is decent. The activity factor is not, because it relies on self-assessment and people are consistently generous with themselves.
Three gym sessions a week is "lightly active", not "very active" — three hours of training spread across 168 hours barely moves the average. Meanwhile someone on their feet all day in a warehouse burns far more than someone who trains hard and then sits for the remaining fifteen hours.
If you're between two levels, pick the lower one. It is easier to add food when you're losing faster than intended than to work out why you aren't losing at all.
How to use this properly
- Take the number as a hypothesis, not a fact.
- Eat at it for two weeks, weighing yourself at the same time each morning.
- Average each week and compare. Daily weight swings of 1–2 kg from water, salt and digestion are normal and meaningless.
- Adjust by 100–200 calories based on what actually happened, not what should have happened.
- Repeat. Your real TDEE emerges from the data within a month.
The deficit that actually works
A deficit of roughly 500 calories a day produces about 0.5 kg (1 lb) of loss a week, since a kilo of fat stores roughly 7,700 calories. As a percentage, 15–25% below maintenance suits most people.
Larger deficits are not proportionally better. They cost more muscle, degrade training quality and sleep, and are far harder to stick to — and adherence, not deficit size, determines outcomes over months. Floors of about 1,200 calories for women and 1,500 for men are the usual guidance without medical supervision.
Macros, briefly
- Protein: 1.6–2.2 g per kg of body weight. The one with strong evidence behind it. It preserves muscle in a deficit and is the most satiating macronutrient.
- Fat: at least 0.6 g per kg. Needed for hormone production and absorbing fat-soluble vitamins. Going very low tends to feel awful.
- Carbohydrate: whatever remains. Primary fuel for hard training. Low-carb diets work for some people, but through appetite control, not metabolic magic.
Calories determine whether weight moves. Macros determine what you lose and whether you can stand the process.
When this calculator won't fit you
Prediction equations are built on averages and misfit at the extremes: very muscular or very tall people, those with a BMI over about 40, pregnant or breastfeeding women, and anyone with a thyroid or metabolic condition. Adolescents still growing need different guidance entirely.
Informational only, not medical or dietary advice. Speak to a doctor or registered dietitian before making significant changes, particularly if you have a health condition or any history of disordered eating.
Frequently asked questions
What is TDEE?
Total Daily Energy Expenditure — everything you burn in a day. It is your BMR (what you would burn lying still) multiplied by an activity factor, which accounts for exercise, movement and digesting food. It is the number you eat around to maintain weight.
How accurate is this?
The Mifflin-St Jeor equation predicts BMR within about 10% for roughly 80% of people, which on a 2,400 calorie target is a range of ±240. The activity multiplier is a much bigger source of error, because most people overestimate how active they are. Treat the result as a starting point, then adjust based on two weeks of actual weight data.
Why did I stop losing weight?
Usually one of three things. Your TDEE fell because you now weigh less and are moving less unconsciously. Your portions crept up — unlogged oils, drinks and bites add up fast. Or you are retaining water, which masks fat loss on the scale for weeks at a time. Trend weight over a fortnight tells you more than any single morning.
Is a very low calorie target a good idea?
Rarely, and not without supervision. Aggressive deficits cost muscle alongside fat, tank your energy and adherence, and are hard to sustain. A deficit of 15–25% below maintenance is the usual sensible range. Do not go below about 1,200 a day for women or 1,500 for men without medical advice.
Do macros matter as much as calories?
For weight change, calories dominate. For how you feel and what you lose, macros matter: adequate protein preserves muscle in a deficit and keeps you fuller, which makes the deficit easier to hold. Roughly 1.6–2.2 g of protein per kg of body weight is well supported for anyone training.