Calorie Deficit Calculator
Find the daily calorie target that puts you in a deficit to lose weight.
Your details
| Lose 1 kg / 2 lb per week | 1,633 kcal |
| Lose 0.5 kg / 1 lb per week | 2,133 kcal |
| Mild loss | 2,383 kcal |
| Maintain | 2,633 kcal |
| Mild gain | 2,883 kcal |
| Gain 0.5 kg / 1 lb per week | 3,133 kcal |
A calorie deficit is the engine of weight loss. Every diet that works, whether it calls itself keto, fasting, or clean eating, succeeds for the same reason: it puts you in a deficit. This calculator shows you the exact daily number to hit for the pace you want.
How a calorie deficit works
Your body needs a certain number of calories each day to maintain its weight, your maintenance level. Eat below it and your body makes up the difference by burning stored fat. Eat above it and you gain. The size of the gap decides how fast you lose.
How big should the deficit be?
A pound of fat holds about 3,500 calories, and a kilogram about 7,700. That gives the classic targets:
| Deficit per day | Weekly loss |
|---|---|
| 250 calories | about 0.25 kg / 0.5 lb |
| 500 calories | about 0.5 kg / 1 lb |
| 1,000 calories | about 1 kg / 2 lb |
A 500 calorie deficit is the sweet spot for most people: fast enough to stay motivated, gentle enough to protect muscle and stick with.
Deficit without losing muscle
The goal is to lose fat, not muscle. Keep protein high, keep strength training, and avoid extreme cuts. Those three signals tell your body to hold on to lean tissue and burn fat instead.
Make the deficit effortless
Knowing the number is easy. Living it is the hard part. SmaartCoach builds a weekly meal plan at your deficit target and lets you scan food to stay on track, so the deficit happens without daily math.
Frequently asked questions
What is a calorie deficit?
A calorie deficit means eating fewer calories than your body burns in a day. It is the one thing every successful weight-loss approach has in common, because your body then draws on stored fat for the missing energy.
How big should my deficit be?
A deficit of about 500 calories a day leads to roughly 0.5 kg or 1 lb of fat loss per week for most people, which is sustainable. Larger deficits lose faster but are harder to stick to and can cost muscle.
Why am I not losing weight in a deficit?
Common reasons are underestimating portions, weekend eating erasing weekday deficits, water retention masking fat loss, or a target that is no longer accurate as your weight drops. Track your trend over 2 to 3 weeks, not day to day.
Do I have to count calories?
Counting helps precision, but you can also run a deficit by controlling portions and prioritizing protein and whole foods. SmaartCoach plans the meals so the deficit is built in without hand counting.
Sources
Reviewed against these authoritative references. Last updated August 2026.
- MedlinePlus, U.S. National Library of Medicine. Metabolism
- U.S. Department of Health and Human Services. Physical Activity Guidelines for Americans
- MedlinePlus, U.S. National Library of Medicine. Body mass index
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