A calorie deficit occurs when you consume fewer calories than your body burns. It is the fundamental mechanism behind all weight loss — regardless of diet type. This calculator takes your Total Daily Energy Expenditure (TDEE) and your target weight loss rate, and gives you a daily calorie target to aim for.
Not sure of your TDEE? Use our Daily Calorie Needs Calculator first, then come back here with your result.
🧮 Calculate Your Calorie Deficit
📊 Your Daily Calorie Targets
Deficit size relative to maintenance (max shown: 30%)
💡 What This Means in Practice
📖 How a Calorie Deficit Works
The 3,500 Calorie Rule
One pound of body fat stores approximately 3,500 calories of energy. To lose one pound per week you need to create a deficit of 3,500 calories over seven days — or 500 calories per day. This is the most widely cited figure in weight loss science and underpins this calculator.
In practice, weight loss is not perfectly linear. The body adapts to reduced intake by lowering metabolism slightly over time, meaning actual results may be slightly slower than predicted. However the 3,500 calorie rule remains a reliable planning tool for most people.
Choosing the Right Deficit Size
0.5 lb per week (250 cal/day deficit) — The most sustainable approach. Small enough that most people don't feel significantly restricted. Best for people who want to make a gradual, lasting change or who have less than 10 lbs to lose.
1 lb per week (500 cal/day deficit) — The most commonly recommended rate. Meaningful enough to see progress, modest enough to be sustainable for most people. Generally considered the sweet spot.
1.5 lbs per week (750 cal/day deficit) — Appropriate for people with more weight to lose. Requires more dietary discipline. Still within the range considered safe without medical supervision for most healthy adults.
2 lbs per week (1,000 cal/day deficit) — The maximum generally recommended without medical supervision. Should only be attempted by people with significant weight to lose. At this rate, preserving muscle mass through adequate protein and resistance training becomes particularly important.
Deficit vs Exercise
A calorie deficit can be achieved through eating less, exercising more, or a combination of both. Research consistently shows that combining moderate dietary restriction with regular exercise produces better long-term results than either approach alone. Use our Calories Burned Calculator to see how exercise contributes to your daily deficit.
What to Eat on a Deficit
The distribution of your calories matters. Prioritising protein (at least 0.7g per pound of body weight) helps preserve muscle mass during weight loss. Use our Protein Intake Calculator to find your daily protein target, and our Macro Calculator to plan your full macro split. Log your daily food intake with our Food Tracker to stay within your calorie target.