Calorie Deficit Calculator
Turn a goal weight and timeframe into the daily calories and deficit you need to hit it.
How to use the calorie deficit calculator
- Enter your maintenance calories (from the TDEE calculator).
- Enter your current and goal weight, and a weekly loss rate.
- Click Calculate for your daily target, deficit and time to goal.
Slow and steady wins
Moderate deficits of 0.25–0.75 kg per week preserve muscle, protect performance, and are far easier to stick to than crash diets. Recalculate as your weight drops.
How big a deficit should you run?
A deficit of about 0.5-1% of body weight per week is sustainable for most people, which usually means 300-700 calories per day. Larger deficits lose weight faster but risk muscle loss, low energy, and rebound eating.
The best deficit is the one you can hold consistently while still training well and sleeping properly. Patience almost always beats severity over a full diet.
Why progress is rarely linear
Water retention, glycogen changes, and hormonal fluctuations mean the scale can stall or jump even in a genuine deficit. Judge progress over two to three weeks, not day to day, and expect the rate to slow as you get lighter, because a smaller body burns fewer calories.
Frequently asked questions
How big should a calorie deficit be?
A deficit of 500 calories a day yields roughly 0.45 kg (1 lb) of fat loss per week. Aggressive deficits risk muscle loss and are hard to sustain.
How many calories is 1 kg of fat?
About 7,700 calories. To lose 1 kg in a week you would need an average daily deficit of around 1,100 calories — usually too steep for most people.
How many calories is one kilogram of fat?
Roughly 7,700 calories. A daily deficit of 550 calories therefore loses about half a kilogram of fat per week, in theory.
Why has my weight loss stalled?
Stalls often come from water retention, an unconsciously smaller deficit as you get lighter, or under-tracking intake. Reassess over a few weeks before making changes.
Will a bigger deficit get me lean faster?
Up to a point, but very large deficits risk muscle loss and burnout. A moderate, sustainable deficit usually produces better body composition in the end.
Related tools
TDEE Calculator
Calculate the calories you burn per day (your TDEE) to set targets for cutting, maintaining, or bulking.
Macro Calculator
Turn your calorie target into daily protein, carbohydrate, and fat goals based on your objective.
Protein Intake Calculator
Find your daily protein target based on your body weight and training goal.