Guide
How Many Calories Is a Calorie Deficit?
Any amount below your maintenance calories is technically a deficit. But the size you pick decides how fast you lose weight and how hard it feels. For most people, the right number is 10 to 25% below maintenance, or roughly 300 to 750 calories a day.
The short version
- Small deficit: 10% below maintenance, or about 200–300 calories a day
- Moderate deficit: 15–20% below, or about 400–500 calories a day
- Large deficit: 25% below, or about 600–750 calories a day
Going beyond 25% for long usually backfires. Hunger climbs, energy drops and you're more likely to lose muscle as well as fat.
Why a percentage works better than "500 calories"
The classic advice is to eat 500 calories less a day. That's a big cut for a small person burning 1,700 calories, and a fairly gentle one for a tall, active person burning 3,000. A percentage of your maintenance number keeps the effort similar whatever your size.
Calorie deficit by maintenance level
| Maintenance (TDEE) | 10% deficit | 20% deficit | 25% deficit |
|---|---|---|---|
| 1,800 kcal | 1,620 kcal | 1,440 kcal | 1,350 kcal |
| 2,000 kcal | 1,800 kcal | 1,600 kcal | 1,500 kcal |
| 2,200 kcal | 1,980 kcal | 1,760 kcal | 1,650 kcal |
| 2,600 kcal | 2,340 kcal | 2,080 kcal | 1,950 kcal |
| 3,000 kcal | 2,700 kcal | 2,400 kcal | 2,250 kcal |
Daily calories to eat. Don't go under about 1,200 for women or 1,500 for men without medical advice.
Not sure of your maintenance number? The TDEE calculator gives it to you in under a minute.
How fast will each deficit work?
A pound of body fat holds about 3,500 calories, and a kilo about 7,700. So:
| Daily deficit | Per week | Per month |
|---|---|---|
| 300 kcal | ≈ 0.6 lb (0.27 kg) | ≈ 2.5 lb (1.2 kg) |
| 500 kcal | ≈ 1 lb (0.45 kg) | ≈ 4 lb (2 kg) |
| 750 kcal | ≈ 1.5 lb (0.7 kg) | ≈ 6.5 lb (3 kg) |
Expect the first week to look faster because of water loss, then settle into these numbers. The 7 day weight loss calculator shows how much of that first drop is water.
Which deficit should you pick?
- Lots of weight to lose: a larger deficit, around 20–25%, is usually fine to start with.
- Within 10–15 lb (5–7 kg) of your goal: a smaller deficit, around 10–15%, helps you keep muscle.
- Training hard for sport or lifting: stay around 10–15% so your workouts don't suffer.
- Older adults: a moderate deficit plus plenty of protein and strength training protects muscle.
A handy safety check: try not to lose more than about 1% of your body weight a week after the first couple of weeks.
Common questions
Is a 300 calorie deficit enough to lose weight?
Yes. A 300-calorie daily deficit leads to around 0.6 pounds (0.27 kg) of fat loss a week. It's slow, but easy to keep up, which makes it a good choice for people close to their goal.
Is a 1,000 calorie deficit too much?
For most people, yes. It can work for people with a lot of weight to lose, ideally with a doctor's support, but it often causes hunger, tiredness and muscle loss.
Should my deficit be a set number or a percentage?
A percentage scales better. 20% below maintenance is about 400 calories for a smaller person and 600 for a larger one, which keeps the effort similar for both.
How do I calculate my calorie deficit?
Find your maintenance calories (TDEE), then subtract 10 to 25%. The calorie deficit calculator does this for you and shows the date you're likely to reach your goal.
This article is general information, not medical advice. If you have a health condition, are pregnant or take regular medication, check with your doctor before changing how you eat.