Calorie Deficit Calculator
Enter your current weight, goal weight, and activity level to get your exact daily calorie target, deficit size, and estimated timeline to reach your goal.
Your Details
Your results will appear here
Fill in your body metrics and goal on the left, then click Calculate My Deficit.
Deficit is just the start. See your full health picture.
A personalised PDF — body fat %, ideal weight, calorie targets, heart rate zones and a starter meal plan, all calculated for your exact numbers.
How It Works
What Is a Calorie Deficit?
Eat less than you burn: Your TDEE is total daily calories burned. Eat below it and your body draws on stored fat.
1 lb fat ≈ 3,500 cal: A 500-cal daily deficit produces ~1 lb of fat loss per week.
TDEE drops as you lose: Recalculate every 4–6 weeks to keep your deficit accurate.
Safe Deficit Ranges
Above 1,000 cal/day risks significant muscle loss.
Tips for Hitting Your Target
Track first: Log everything for 2 weeks before cutting — you may already be close.
Prioritise protein: 1.6–2 g/kg body weight preserves muscle and keeps you fuller.
Weigh weekly: Daily ±1–2 lb swings are water. Only the weekly trend matters.
Nutrition > exercise: Exercise increases TDEE slightly but can't compensate for untracked eating.
Activity Level Guide
- Sedentary: Desk job, no exercise
- Lightly Active: Exercise 1–3 days/week
- Moderately Active: Exercise 3–5 days/week
- Very Active: Hard exercise 6–7 days/week
- Extra Active: Physical job + daily exercise
Seek medical advice if:
- • Weight unchanged after 3–4 weeks
- • History of disordered eating
- • Pregnant or breastfeeding
- • Thyroid or metabolic condition
Calorie Needs Calculator
Calculate your TDEE and daily calorie target by activity level.
BMR & TDEE Calculator
Find out how many calories your body burns at rest and daily.
Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy method.
Ideal Weight Calculator
Calculate your ideal weight using four peer-reviewed formulas.
Calorie Deficit Calculator — Common Questions
What is a calorie deficit?
A calorie deficit means eating fewer calories than your Total Daily Energy Expenditure (TDEE). The shortfall is made up from stored body fat, causing gradual weight loss. Your TDEE is your BMR (calories at rest) multiplied by your activity level.
How big should my calorie deficit be?
A 500-calorie daily deficit is the most recommended starting point — it produces roughly 1 lb of fat loss per week with minimal muscle loss. Smaller deficits (250 cal) are more sustainable long-term; larger ones (>750 cal) increase muscle loss and hunger.
What is the minimum safe calorie intake?
Most guidelines recommend women eat no fewer than 1,200 cal/day and men no fewer than 1,500 cal/day without medical supervision. Below these levels you risk nutrient deficiencies, significant muscle loss, and metabolic slowdown.
Why does my timeline change as I lose weight?
As you lose weight your TDEE decreases because there is less mass to maintain. The same food intake creates a smaller deficit over time. Recalculate your calorie target every 4–6 weeks to keep your results on track.
Can I lose weight faster with a bigger deficit?
Larger deficits speed up initial weight loss but also increase muscle breakdown, hunger, and metabolic adaptation. Research supports a maximum deficit of 500–750 cal/day for fat loss while preserving muscle. Two lbs/week (1,000 cal deficit) is the generally recommended upper limit.
How accurate is this calculator?
The Mifflin-St Jeor equation is the most accurate general TDEE formula for most adults, but individual metabolism varies by ±10–15%. Use the results as a starting point, track your weight weekly for 2–3 weeks, and adjust by 100–200 cal if progress stalls.
Sources used on this page
This calculator uses the Mifflin-St Jeor equation to estimate TDEE, then applies the selected deficit. Individual metabolic rate varies by ±10–15%. Results are for educational use only and are not a substitute for personalised medical advice.