Calorie Deficit Calculator
Estimate how many calories you burn per day (TDEE), then see the daily target that creates your chosen deficit. Based on the Mifflin-St Jeor equation.
How it's calculated
The calculator uses the Mifflin-St Jeor equation — generally the most accurate of the standard formulas — to estimate your BMR (what you'd burn at complete rest), multiplies it by an activity factor to get your TDEE (total daily burn), then subtracts the deficit needed for your chosen pace. One kilogram of body fat stores roughly 7,700 kcal, so 0.5 kg per week means a deficit of about 550 kcal per day.
Treat the number as a starting point
Every formula estimates; your body decides. Real-world burn varies by ±10% or more between people with identical stats. The honest workflow: eat near the target for two to three weeks, weigh daily, and read your weekly trend. Trend matching your chosen pace? The number is right for you. Slower? Trim 100–200 kcal or add movement. Faster than 1 kg per week? Eat a little more — you're likely losing muscle.
You don't have to count calories
Knowing your target doesn't obligate you to log every meal. Many people use the number once to calibrate portions, then just track their weight — if the trend moves at the right pace, the eating is working, whether or not it's being written down.
That trend-first approach is exactly what Weightnote is built for — and why it has no food diary. See also What's a Healthy Rate of Weight Loss?
Common questions
- How many calories should I eat to lose weight?
- Roughly your maintenance calories (TDEE) minus 500 kcal for 0.5 kg (1 lb) per week of loss. For most adults that lands between 1,500 and 2,300 kcal/day — enter your stats above for a personal estimate.
- What is a safe calorie deficit?
- About 250–1,000 kcal/day, corresponding to 0.25–1 kg per week. Going below roughly 1,200 kcal/day (women) or 1,500 kcal/day (men) is not recommended without medical supervision.
- What's the difference between BMR and TDEE?
- BMR is what your body burns at complete rest; TDEE adds everything else — walking, workouts, fidgeting, digestion. You lose weight when you consistently eat below TDEE, not BMR.
- Why am I not losing weight in a calorie deficit?
- Usually one of three things: the deficit is smaller than calculated (formulas estimate, portions creep), water retention is masking fat loss on the scale, or not enough time has passed. Check your weight trend over three weeks before concluding it isn't working.
- Do I need to count calories to lose weight?
- No. The deficit still has to exist, but you can create it with portion habits, food choices and activity — then verify it's working by watching your weekly weight trend instead of logging meals.
This calculator is for general information only and is not medical advice. Talk to a doctor before making significant changes to your diet or exercise, especially if you have a health condition, are pregnant, or are under 18.