Calorie & BMR Calculator
TrendingFind your BMR and daily calorie needs for maintenance, loss or gain.
What is the Calorie & BMR Calculator?
A BMR and calorie calculator estimates your Basal Metabolic Rate (the calories your body burns at complete rest just to function) and your total daily energy needs once activity is factored in. It works using the Mifflin-St Jeor equation — for men, BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women, the same calculation minus 161 instead of plus 5 — then multiplies that BMR by an activity multiplier (ranging from 1.2 for sedentary to 1.9 for extremely active) to estimate your Total Daily Energy Expenditure (TDEE), the calories needed to maintain your current weight. To estimate weight loss or gain targets, subtract or add roughly 500 calories a day from your TDEE for a gradual, sustainable change — individual needs vary, so consult a health professional for tailored advice.
How it works
BMR (Basal Metabolic Rate) is an estimate of how many calories your body burns at complete rest just to maintain basic functions like breathing, circulation and cell repair. It's calculated from your weight, height, age and sex using an established formula (commonly the Mifflin-St Jeor or Harris-Benedict equations). Your total daily calorie needs — often called TDEE (Total Daily Energy Expenditure) — are then estimated by multiplying your BMR by an activity multiplier that reflects how active you typically are.
UK context
"Maintenance calories" is the TDEE figure needed to keep your weight roughly stable. Eating consistently below that figure creates the calorie deficit needed for weight loss, while eating above it supports weight gain — but these formulas are population-level estimates, and individual metabolism varies for reasons the formulas can't fully capture (genetics, hormonal factors, muscle mass, and more).
Tips
- Treat the calculated figure as a starting estimate, not an exact number — track your actual weight change over a few weeks against your intake and adjust from there.
- Being consistently honest about your activity level matters a lot for accuracy — most people tend to overestimate how active they are, which inflates the estimated calorie needs.
- A moderate, sustainable calorie deficit or surplus is generally considered healthier and more maintainable long-term than an extreme one — consult a healthcare professional before making significant dietary changes.
Frequently asked questions
What's the difference between BMR and TDEE?
BMR is the calories your body burns at complete rest for basic functions. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor, giving a fuller estimate of total daily calorie burn including movement and exercise.
How accurate are calorie calculators?
These formulas give a population-level estimate based on established equations, but individual metabolism varies due to genetics, muscle mass, hormones and other factors — they're a useful starting point, not an exact measurement, and results are best combined with tracking your actual progress.
How many calories should I eat to lose weight?
Weight loss generally requires eating consistently below your TDEE (maintenance calories) to create a calorie deficit. The right size of deficit depends on individual goals and circumstances — speak to a healthcare professional or registered dietitian for personalised guidance.
A quick note
These are general estimates based on established formulas, not personalised medical or nutritional advice. Speak to a GP, registered dietitian or other healthcare professional before making significant changes to your diet.