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Calorie Deficit Calculator – Weight Loss Planner

Pick a target weight and a pace — gradual, moderate or intensive — and get your daily calorie target and the estimated weeks to get there.

Free · No sign-up · Works on phone and computerOpen the tool full-screen →

About this tool

Weight loss planning is arithmetic plus honesty. The arithmetic: your BMR from Mifflin-St Jeor, multiplied by your activity factor, gives the TDEE that maintains your current weight; eat below it by 250 kcal a day and the standard guide says you lose about 0.25 kg a week, by 500 for about 0.5 kg a week, by 1,000 for about 1 kg a week. The honesty: bodies are not spreadsheets. Loss runs fast early (water), slows later (a lighter body burns less, and appetite pushes back), and the intensive pace takes many people below safe minimum intakes — which is why this planner shows all three paces side by side and warns when a target drops under 1,200 kcal (women) or 1,500 kcal (men).

A note on health results: every figure this tool gives is an estimate from a standard formula — it is not medical advice and it does not diagnose anything. Bodies vary, and formulas cannot see your health history. Use the result as a starting point, and consult a clinician or registered dietitian for personal health decisions.

How to use it

  1. Enter your details — sex, age, current weight and height set your BMR and TDEE.
  2. Set your activity level — honestly; it moves your maintenance calories a lot.
  3. Enter a target weight — in the same unit, kg or lbs.
  4. Pick a pace — gradual 0.25, moderate 0.5 or intensive 1 kg a week — and read your daily target and estimated weeks.

What you get

Frequently asked questions

How big a deficit do I need to lose 0.5 kg a week?
About 500 kcal a day below your TDEE is the standard guide — the figure this planner uses for its moderate pace. It comes from the rough rule that a kilogram of body fat stores around 7,700 kcal; real-world loss varies, especially in the first weeks.
Why is the intensive pace not always a good idea?
A 1,000 kcal daily deficit is a large cut: hunger, fatigue and muscle loss all rise, adherence falls, and for smaller or less active people it can push intake below 1,200–1,500 kcal a day, the range generally treated as needing medical supervision. Gradual and moderate paces reach the same target a few weeks later and are far more likely to stick.
Why does weight loss slow down over time?
A lighter body needs fewer calories: your BMR and TDEE are calculated from your current weight, so the same daily target becomes a smaller deficit as you lose. Recheck this planner every 5 kg or so and adjust the target — a plateau usually means the maths moved, not that it stopped working.

Related free tools

Calorie Calculator (TDEE)The maintenance figure every deficit is subtracted from. BMR CalculatorYour resting burn, the base of the whole plan. BMI CalculatorSee where your target weight sits in the WHO bands.

From the blog

New to this one? The blog walks through how to use the Calorie Deficit Calculator step by step — and what it is good for.

Read the Calorie Deficit Calculator guide →