🥗 Calorie Deficit Calculator
Find how many calories to eat each day to reach your goal weight at a safe, steady pace.
Quick answer: A 30-year-old man (175 cm, 85 kg, moderately active) burns about 2,788 kcal a day. To lose 0.5 kg a week he should eat about 2,238 kcal a day, reaching 75 kg in about 20 weeks.
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Calorie Deficit Calculator inputs
Result
Eat about
2,238 kcal/day
to lose 0.5 kg a week
| Maintenance calories (TDEE) | 2,788 kcal |
| Daily deficit | −550 kcal |
| Daily target | 2,238 kcal |
- Weight to lose
- 10 kg
- Time to goal
- 20 weeks
- BMR
- 1,799 kcal
How the calorie deficit is calculated
First the calculator estimates your maintenance calories (TDEE) from your basal metabolic rate (Mifflin–St Jeor) and activity level. It then subtracts the deficit needed for your chosen rate of loss.
Daily deficit = weekly loss × 7,700 kcal/kg ÷ 7 (or × 3,500 kcal/lb ÷ 7) · Target = TDEE − deficit
Weeks to goal = weight to lose × 7,700 ÷ (daily deficit × 7)
Worked example
A 30-year-old man, 175 cm, 85 kg and moderately active: BMR = 850 + 1,093.75 − 150 + 5 = 1,798.75 kcal; TDEE = 1,798.75 × 1.55 ≈ 2,788 kcal. Losing 0.5 kg a week needs 0.5 × 7,700 ÷ 7 = 550 kcal a day, so the target is 2,238 kcal. Losing 10 kg takes about 20 weeks.
Choosing a safe pace
| Weekly loss | Daily deficit | Best for |
|---|---|---|
| 0.25 kg / 0.5 lb | ≈ 275 / 250 kcal | Small amounts to lose, athletes |
| 0.5 kg / 1 lb | ≈ 550 / 500 kcal | Most adults |
| 0.75 kg / 1.5 lb | ≈ 825 / 750 kcal | Larger bodies with more to lose |
| 1 kg / 2 lb | ≈ 1,100 / 1,000 kcal | Short phases only, ideally supervised |
If the requested deficit would push intake below 1,200 kcal (women) or 1,500 kcal (men), the target is held at that minimum and the timeline is lengthened accordingly.
Tips
- Keep protein high (about 1.6 g per kg) and lift weights to protect muscle while dieting.
- Judge progress on a weekly average weight, not a single weigh-in.
- Recalculate after every 4–5 kg lost, as maintenance calories fall.
For general information only – not medical advice. Consult a healthcare professional.
Frequently asked questions
How big should my calorie deficit be?
A deficit of 250–550 kcal a day, giving 0.25–0.5 kg (0.5–1 lb) of loss per week, is sustainable for most people. Larger deficits increase muscle loss, hunger and the risk of nutrient gaps.
What is the minimum number of calories I should eat?
Common guidance is no fewer than about 1,200 kcal a day for women and 1,500 kcal for men unless supervised by a doctor. The calculator never sets a target below these floors.
Why has my weight loss slowed down?
As you lose weight your maintenance calories fall, so the same intake becomes a smaller deficit. Water retention also masks fat loss for days at a time. Recalculate every few kilograms.
Is 1 kg of fat really 7,700 calories?
It is a useful rule of thumb (about 3,500 kcal per pound). Real-world loss is usually a little slower over time because the body adapts, so treat the timeline as a best-case estimate.