A calorie deficit means eating fewer calories than you burn. One kilogram of body fat stores roughly 7,700 kcal, so a daily deficit of about 550 kcal loses around 0.5 kg a week. For most people a deficit of 300–500 kcal a day is the sustainable range; this calculator works out your number from your maintenance calories.
For adults aged 18 and over. An estimate for general guidance, not medical advice. Free to use, no sign-up, and nothing you enter leaves your device.
Daily deficit = weekly loss (kg) × 7,700 ÷ 7
Target calories = maintenance calories (TDEE) − daily deficit
Maintenance calories come from the Mifflin-St Jeor equation and your activity level. The calculator will not set a target below 1,200 kcal for women or 1,500 kcal for men, the minimums commonly used for dieting without medical supervision. If your chosen pace would go below that, it shows the floor and the slower pace you can expect instead.
A 30-year-old man, 70 kg and 170 cm, training 3–5 days a week maintains on 2,508 kcal. To lose 0.5 kg a week he needs a deficit of 550 kcal, so his target is 1,958 kcal a day. Losing 5 kg at that pace takes about 10 weeks.
| Weekly loss | Daily deficit | Target calories | Time to lose 5 kg |
|---|---|---|---|
| 0.25 kg | 275 kcal | 2,233 kcal | 20 weeks |
| 0.5 kg | 550 kcal | 1,958 kcal | 10 weeks |
| 0.75 kg | 825 kcal | 1,683 kcal | 7 weeks |
| 1 kg | 1,100 kcal | 1,500 kcal (floor) | 6 weeks |
"(floor)" means the full deficit would go below the 1,500 kcal minimum for men, so the target is held there and loss is slower. Real-world loss is rarely this linear: water shifts mask fat loss week to week, and maintenance calories fall as you get lighter.
Choose the smallest deficit that still gives you progress you can see. A pace of 0.5–1% of your body weight a week keeps energy, training and muscle intact; faster than that and most people rebound. Keep protein at 1.6–2.2 g per kg and lift weights, so the weight you lose is fat. Recalculate after every 4–5 kg lost, because a lighter body burns less.
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Eat 300–500 kcal below your maintenance calories. For most people that gives a loss of roughly 0.25–0.5 kg a week, a pace that is easy to sustain and protects muscle. Work out your maintenance calories first, then subtract the deficit.
About 1,100 kcal a day, because 1 kg of body fat stores roughly 7,700 kcal. That is an aggressive deficit and only realistic for people with high maintenance calories. For most people 0.5 kg a week, a deficit of about 550 kcal a day, is the better target.
1,200 kcal is the minimum commonly advised for women, and 1,500 kcal for men, when dieting without medical supervision. Below that it becomes very hard to get enough protein, vitamins and minerals, and muscle loss and fatigue become likely. Most people lose weight well above these floors.
The common reasons are that your maintenance calories have dropped as you lost weight, portions have crept up without you noticing, or water retention is hiding fat loss on the scale. Recalculate your target after every 4–5 kg lost, weigh food for a week to check your intake, and judge progress on a two-week average rather than a single day.
Not much, if you do three things: keep the deficit moderate, eat 1.6–2.2 g of protein per kg of body weight, and keep doing strength training. Crash diets with low protein and no lifting are what cause muscle loss.
A calculator gives you a target. Coach Himanshu builds the workout and Indian diet plan that gets you there, and adjusts it as your body changes.