Calorie Deficit Calculator for Weight Loss
Enter your TDEE (total daily energy expenditure) and your weekly weight-loss goal, and this calorie deficit calculator for weight loss instantly tells you how big a daily deficit you need and exactly how many calories to eat each day to hit it — with a safety check so your target never drops below healthy minimums.
Enter your numbers
Total daily energy expenditure — your maintenance calories. Don't know it? Try our TDEE calculator first.
0.5–1 lb/week is a moderate pace; up to 2 lb/week is aggressive.
Your results
| Weekly deficit | – |
|---|---|
| Monthly loss (estimate) | – |
| Deficit as % of TDEE | – |
How to use this calculator
Start with your TDEE — the number of calories you burn in a typical day, including exercise. If you don't know it, estimate it with a TDEE or maintenance-calorie calculator first; an accurate starting number makes everything downstream accurate.
Next, pick your weekly weight-loss goal. A goal of 0.5 lb per week means a gentle 250-kcal daily deficit; 1 lb per week means 500 kcal per day. Most people do best starting at 1 lb per week and adjusting after two to three weeks of tracking.
Your target daily intake is the number to eat each day. Track your food for a week and compare your average intake to this target — small misses are fine, it's the weekly average that matters.
How it works
The math behind weight loss is the 3,500-kcal rule: one pound of body fat stores roughly 3,500 kilocalories of energy. To lose W pounds in a week, you need a total weekly deficit of W × 3,500 kcal, spread evenly across the seven days:
Daily deficit = (weekly goal in lb × 3,500) ÷ 7 = weekly goal × 500 kcal
Your target intake is then simply your maintenance level minus the deficit:
Target daily intake = TDEE − daily deficit
For example, with a TDEE of 2,500 kcal/day and a goal of 1 lb per week: deficit = 1 × 500 = 500 kcal/day, so target intake = 2,500 − 500 = 2,000 kcal/day.
The 3,500-kcal figure is a long-standing estimate, not a law of physics: real bodies adapt (metabolic adaptation, water shifts, activity changes), so treat projected timelines as estimates and adjust your goal based on actual scale and tape-measure trends over 2–4 weeks.
What makes this different from a timeline planner?
Our weight loss timeline planner answers "when will I reach my goal weight?" by projecting a date from your starting and target weight. This calculator answers the more practical daily question: "how many calories should I eat today?" Use this one for your daily target, and the planner for the big-picture date.
Frequently asked questions
What is a safe calorie deficit for weight loss?
A daily deficit of 300 to 500 kcal, or roughly 0.5 to 1 lb per week, is the range most experts consider safe and sustainable. Deficits larger than about 1,000 kcal per day (2 lb per week) are generally only appropriate under medical supervision.
How many calories should I eat to lose one pound per week?
One pound of body fat holds about 3,500 kcal, so losing a pound a week needs a daily deficit of 500 kcal. Subtract 500 from your TDEE: for example, a TDEE of 2,500 kcal/day gives a target intake of 2,000 kcal/day.
Can I eat fewer than 1,200 calories a day to lose weight faster?
Not without medical supervision. Intakes below about 1,200 kcal/day for women or 1,500 kcal/day for men can cause nutrient deficiencies, muscle loss, and metabolic slowdown. If the calculator shows your target below these floors, choose a smaller deficit instead.
How is this different from a weight loss timeline planner?
This calculator answers "how many calories should I eat today": it turns your TDEE and weekly goal into a daily deficit and a daily intake target. A weight loss timeline planner answers "when will I reach my goal weight" by projecting the date from your starting and target weight.