For most people the ideal calorie deficit is 300–500 calories per day, producing roughly 0.3–0.5 kg of fat loss per week. A reliable rule is to target 0.5–1% of your body weight in weekly loss. Lean people and those who train hard should use the smaller end to protect muscle; people with more body fat can safely go larger.
Size your deficit to a goal
Enter a goal weight and pace — get your daily target, deficit, and timeline. Free, no signup.
The science: deficit to weekly loss
Body fat stores roughly 7,700 calories per kilogram (about 3,500 per pound). So your weekly weight loss is simply your total weekly deficit divided by 7,700:
Weekly fat loss
This is why the classic "500 calories a day = half a kilo a week" guidance exists. It's an approximation — water weight and metabolic adaptation make real-world results bumpier — but it's accurate enough to plan with.
Deficit sizes, compared
| Daily deficit | Weekly loss | Best for | Risk |
|---|---|---|---|
| 200–300 kcal | ~0.2 kg/wk | Lean people, muscle preservation, athletes | Slow — can feel discouraging |
| 400–500 kcal | ~0.4–0.5 kg/wk | Most people — the standard recommendation | Low — the reliable default |
| 500–750 kcal | ~0.5–0.7 kg/wk | Higher body fat, faster results wanted | Moderate — track protein carefully |
| 750–1,000 kcal | ~0.7–1 kg/wk | Significant obesity, medical supervision | High — muscle & nutrient risk |
The percentage-of-bodyweight rule
A fixed 500 kcal deficit means very different things to a 60 kg and a 120 kg person. A better way to scale it is by body weight: aim to lose 0.5–1% of your body weight per week.
- 0.5%/week — best for lean people or anyone prioritising muscle retention.
- 0.7%/week — a solid middle ground for most.
- 1%/week — fine for people with more body fat to lose, harder to sustain long-term.
The Calorie Deficit Calculator applies this automatically: you choose a goal weight and pace, and it returns the daily target, the deficit, and an estimated finish date — with a built-in floor so it never recommends under-eating.
Calorie floors and safety
If a target deficit would push you below these floors, the fix isn't to eat less — it's to lose more slowly, or to raise your TDEE by adding daily movement. Walking is the most underrated fat-loss tool because it widens your deficit without spiking hunger.
When and how to adjust
Your deficit isn't set-and-forget. As you lose weight, your TDEE drops, so the same intake becomes a smaller deficit. Re-check every 4–6 kg or whenever progress stalls for 2–3 weeks:
- Confirm you're tracking accurately first — underlogging mimics a plateau. (See how accurate calorie tracking is.)
- If the trend is genuinely flat for 2–3 weeks, drop your target by 100–150 kcal, or add ~2,000 daily steps.
- Use weekly weight averages, not single days — daily weight swings 1–2 kg from water and digestion.
Hold your deficit, every single day
NutriBalance sets your deficit target and counts down remaining calories in real time as you log. Streaks and daily missions turn "stay in a deficit for 12 weeks" into a daily game you actually keep up. 14-day free trial, no card required.
Start your free trial →FAQ
For most people, 300–500 calories per day — roughly 0.3–0.5 kg of fat loss per week, or 0.5–1% of body weight weekly. Lean people and hard trainers should use the smaller end. Size yours with the free Calorie Deficit Calculator.
A 1,000 kcal/day deficit (~1 kg/week) is only appropriate for people with higher body fat, ideally under medical supervision. It raises the risk of muscle loss, low energy, nutrient gaps, and rebound hunger. Most people do better with a 500 kcal deficit.
As a guideline, don't drop below 1,200 kcal/day (women) or 1,500 (men) without medical supervision, and avoid eating below your BMR for long periods. If your deficit pushes you near these floors, lose weight more slowly or add activity instead.
Usually it's underlogged intake, water-weight masking fat loss, or a TDEE that has dropped as you've lost weight. Verify your tracking, use weekly averages, and if the trend is truly flat for 2–3 weeks, cut 100–150 kcal or add steps. Recalculate your deficit every 4–6 kg.