Calorie Deficit Basics
- •A calorie deficit means eating below your TDEE (total daily energy expenditure).
- •Roughly 7,700 kcal ≈ 1 kg of body fat — a 550 kcal/day deficit ≈ 0.5 kg/week.
- •Safe sustainable pace: 0.25-0.75 kg per week. Faster usually means muscle and water, not fat.
- •Don't go below ~1,500 kcal/day (men) or ~1,200 kcal/day (women) without medical supervision.
The Real Problem This Solves
"Just eat less" fails because people guess the number. Cut too little and nothing happens; cut too much and you lose muscle, feel terrible, and rebound within a month.
Weight loss is arithmetic before it is willpower: a specific daily intake, held consistently. This calculator turns your body stats and a chosen pace into that exact number — and tells you honestly how long reaching your goal weight will take.
How Your Deficit Is Calculated
First your BMR (Mifflin-St Jeor equation), then your maintenance calories (TDEE = BMR × activity factor). Your chosen pace sets the deficit: 1 kg of body fat stores about 7,700 kcal, so 0.5 kg/week needs a 550 kcal daily deficit. Your target intake = TDEE − deficit.
Example: Arjun, 28, weighs 75 kg at 175 cm and trains 3-5 days a week. His TDEE is about 2,649 kcal. Choosing 0.5 kg/week, his daily target is roughly 2,100 kcal — and losing 5 kg takes about 10 weeks. Not thrilling, but real: that's 5 kg that stays off, versus a crash diet's 5 kg that comes back.
| Pace | Daily Deficit | Time to Lose 5 kg |
|---|---|---|
| 0.25 kg/week | ~275 kcal | ~20 weeks |
| 0.5 kg/week | ~550 kcal | ~10 weeks |
| 0.75 kg/week | ~825 kcal | ~7 weeks |
| 1 kg/week | ~1,100 kcal | ~5 weeks (often unsustainable) |
Frequently Asked Questions
How big should my calorie deficit be?
For most people, 500-600 kcal/day (about 0.5 kg/week) is the sweet spot: fast enough to see progress, small enough to keep energy, muscle, and sanity. Go gentler if you are lighter or very active; never let intake fall below the safe minimums.
Why 7,700 calories per kilogram?
One kg of adipose (fat) tissue stores roughly 7,700 kcal of energy. It is an approximation — real-world loss includes water and some lean mass — but it is the standard used for planning deficits and it works well over multi-week periods.
Is a 1,000+ calorie deficit safe?
Rarely, and not for long. Very large deficits accelerate muscle loss, tank your energy and training quality, and are strongly linked to rebound weight gain. If the calculator shows your target below 1,500 kcal (men) or 1,200 kcal (women), pick a slower pace.
Why has my weight loss stalled on the same calories?
As you lose weight, your TDEE drops — a 70 kg body burns fewer calories than a 80 kg one — and metabolism adapts slightly. Recalculate your deficit every 4-5 kg lost, and expect week-to-week fluctuations from water weight.
Related Calculators
Got your daily target?
Make sure the goal weight itself is right for your height. Check your healthy range with our Ideal Weight Calculator before you commit to a number.
Open Ideal Weight Calculator →