Energy · free tool
Calorie Calculator
A daily calorie target for your goal, at a rate you can actually hold.
Your result
A daily calorie target for your goal, at a rate you can actually hold. Fill in the boxes and press Calculate — nothing is sent anywhere and no account is needed.
How this is worked out
- Maintenance is either the TDEE you entered, or Mifflin-St Jeor × an activity factor if you asked us to work it out.
- Fat loss subtracts 10% (gentle), 20% (standard) or 25% (faster). Muscle gain adds 5%, 10% or 15%. A percentage rather than a fixed number, so the same pace means the same thing to a 55 kg person and a 105 kg one.
- The result is then floored at 1,200 kcal for women and 1,500 kcal for men. If the arithmetic goes under, the floor is what you get and the page says so.
Sources
- Mifflin & St Jeor (1990). The resting-energy equation that replaced Harris–Benedict; it is the one most clinical practice uses. PMID 2305711
- Hall et al. (2011) on why the 7,700 kcal-per-kilogram rule overstates long-run loss: energy expenditure falls as body mass does, so a fixed deficit slows down rather than running in a straight line. PMID 21872751
These are population equations. They describe averages well and individuals only roughly — which is what makes them a starting point rather than a prescription. Nothing here is medical advice.
The thinking
Why there is a floor
Why there is a floor
Any calculator can divide. Below roughly 1,200 kcal for a woman or 1,500 for a man, the arithmetic keeps working and the plan stops being one: protein and fibre become almost impossible to hit, hunger stops being a matter of discipline, training quality falls, and a larger share of what you lose is muscle rather than fat.
So this one refuses. It returns the floor, tells you what the raw number was, and points at the actual solution — a longer timeframe. Iron Katia does not sell extremes, and a calculator that quietly prints 900 kcal is selling one.
Questions
Straight answers.
- How fast should I lose weight?
- For most people, around 0.5–1% of body weight a week. Faster is possible and it costs you: more muscle, worse training, and a much lower chance of holding onto the result.
- Do I need to eat this exactly every day?
- No. It is a weekly average worn as a daily number. A high day and a low day that average out are the same thing to your body and much easier to live with.
- My weight is not moving. Is the number wrong?
- Possibly, and that is expected — it is an estimate. Give it a fortnight of consistent intake, weigh under the same conditions, and adjust by about 10% rather than starting again.
Keep going
One number is a reading. A trend is progress.
Every calculator here gives you a starting point and nothing more. What turns it into something useful is logging what you actually do against it — which is free, takes a minute a day, and is where the 14-day START HERE challenge begins.
Start freeNo card, no plan. Or see what coaching adds.