Calorie Deficit Calculator
Daily calorie target and timeline for each weekly weight-loss rate
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A safe deficit is about 0.25–0.75 kg (0.5–1.5 lb) per week — never below ~1200 kcal/day. Faster loss raises the risk of muscle loss and rebound. Pair the deficit with enough protein and strength training.
How to read your result
The table shows three weekly loss rates — 0.25, 0.5 and 0.75 kg (0.5, 1 and 1.5 lb) — each with the daily calorie target that produces it and, if you entered your weights, the estimated weeks to reach your goal. For most people 0.5 kg (about 1 lb) per week is the sweet spot between visible progress and sustainability. For safety, the calculator never recommends eating below 1,200 kcal per day.
How to use this calorie deficit calculator
Enter your daily maintenance calories — the amount you burn per day; if you don't know it, get it from our TDEE calculator first. Current weight and goal weight are optional, but adding them unlocks an estimate of how many weeks each plan will take. You can switch between kg and lb at any time, and one tap on Calculate builds a comparison table of three weight-loss paces — no sign-up needed.
The formula and the science behind it
The math rests on the energy density of body fat: roughly 7,700 kcal per kilogram (3,500 kcal per pound), a figure that traces back to Max Wishnofsky's 1958 analysis. Your daily deficit is simply the weekly rate times 7,700 divided by 7 — so losing 0.5 kg per week requires a deficit of about 550 kcal per day. It's the same energy accounting dietitians use worldwide, applied to your own maintenance number.
Limits and practical tips
This estimate keeps TDEE constant. It does not model metabolic adaptation, water changes or a changing weight curve. Actual results may differ.
Frequently Asked Questions
- What is a calorie deficit?
- A calorie deficit means eating fewer calories than you burn, which forces your body to use stored energy and leads to weight loss. The size of the deficit determines how fast you lose, with about 7,700 kcal roughly equal to one kilogram of fat.
- How does the calorie deficit calculator work?
- Enter your maintenance calories to compare daily calorie targets for several weekly loss rates. To also estimate weeks to your goal, enter both your current weight and goal weight. Those weight fields are optional; maintenance calories alone cannot determine the time to your goal.
- What is a safe rate of weight loss?
- A loss of about 0.5-1% of body weight per week, often around 0.25-1 kg, is widely considered safe and sustainable. Larger deficits risk muscle loss, fatigue, and rebound. Slower, steady deficits are usually easier to maintain long term.