Calorie deficit calculator
Find the daily calorie target that puts you in a deficit, the starting point for losing weight. Enter your details and we'll show your maintenance calories and how fast you'd lose at your chosen pace.
Calorie deficit example: 0.5 kg per week
Consider a 30-year-old man who weighs 75 kg, is 175 cm tall, and selects moderate activity. The Mifflin-St Jeor formula estimates his BMR as 10 × 75 + 6.25 × 175 − 5 × 30 + 5 = 1,699 kcal/day. Applying the 1.55 activity multiplier gives a TDEE of about 2,633 kcal/day.
A goal of 0.5 kg per week represents about 3,850 kcal per week, or 550 kcal per day. The calculation is therefore 2,633 − 550 = 2,083 kcal/day. That is a starting intake estimate, not a guaranteed rate of loss. The example assumes the selected activity multiplier reflects an average week and uses 7,700 kcal as an approximation for one kilogram of weight change; actual scale trends also reflect water, intake measurement, and changing activity. Once calories are set, the macro calculator can divide them into protein, carbohydrate, and fat targets.
What a calorie deficit actually is
A calorie deficit means eating fewer calories than your body burns in a day. When you do, your body makes up the difference from stored energy, mostly fat, and you lose weight. It's the one mechanism every diet has in common, whether it calls itself keto, fasting, or "clean eating."
The calculator does this in two steps. First it estimates your total daily energy expenditure (TDEE), the calories you burn to maintain your current weight. Then it subtracts an amount that matches the weekly loss rate you picked, since a kilogram of body fat stores roughly 7,700 kcal (a pound, about 3,500 kcal).
How fast should you lose?
For most people, 0.5–1% of bodyweight per week is a sustainable pace, fast enough to see progress, slow enough to keep muscle and your sanity. A 500 kcal daily deficit (about 0.5 kg / 1 lb a week) is the classic starting point. Bigger deficits work on paper but get harder to stick to, and that's what actually decides results.
We cap targets at a sensible floor (1,500 kcal for men, 1,200 for women). If your chosen rate would push you below that, slow down or speak to a doctor or dietitian first. Eating too little backfires: you lose muscle, feel awful, and rebound.
The hard part isn't the number, it's logging
A target only works if you actually track what you eat against it, and that's where most people quit. Manual database search for every meal is tedious. Wisely takes a photo of your plate and estimates the calories and macros in seconds, so staying in your deficit doesn't feel like homework.
Frequently asked questions
What is a good calorie deficit to lose weight?
About 500 kcal per day is a common, sustainable target, roughly 0.5 kg (1 lb) of fat loss per week. Larger deficits speed things up but are harder to sustain and risk muscle loss, so most people do best between 300 and 750 kcal per day.
How is the calorie deficit calculated?
We estimate your basal metabolic rate with the Mifflin-St Jeor equation, multiply by an activity factor to get your maintenance calories (TDEE), then subtract the energy that matches your chosen weekly loss rate (about 7,700 kcal per kg of body fat).
How many calories to lose 1 pound a week?
One pound of body fat stores roughly 3,500 kcal, so losing a pound a week means an average deficit of about 500 kcal per day below maintenance. Enter your details above for your exact number.
Why am I not losing weight in a deficit?
Usually it's one of three things: the deficit is smaller than you think (untracked snacks, oils, and drinks add up fast), water retention is masking fat loss on the scale, or your estimate is off. Track honestly for two to three weeks before changing anything.
More free tools
Hit your deficit without the spreadsheet.
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