SCIENTIFIC FAT LOSS TOOL

Calorie Deficit Calculator

Calculate your personalized maintenance intake, daily calorie deficit target, and projected milestone date to reach your goal weight.

Multiplier: ×1.375
-1 lbs/week (-500 kcal/day)
Maintenance TDEE
2,449kcal/day
BMR: 1,781 kcal
Required Daily Deficit
-500kcal/day
Pace: -1 lbs/week
Your Daily Calorie Target
1,949kcal/day
Eat this daily to hit your pace
Estimated Goal Milestone (15 lbs total fat loss)

~15 weeks (Dec 24, 2026)

As you lose weight, your true expenditure slows down. Use AdapTDEE to dynamically adjust your targets and avoid plateaus.

The Science of a Calorie Deficit

Energy balance is governed by the first law of thermodynamics. When total energy expenditure exceeds total dietary intake, your body oxidizes stored adipose tissue and glycogen stores to supply the required energy deficit.

01 / BMR

Basal Metabolic Rate

The baseline calories burned by vital organs (brain, liver, heart, lungs) at complete rest.

02 / TDEE

Total Daily Expenditure

BMR multiplied by physical activity, intentional exercise, and the thermic effect of food (TEF).

03 / DEFICIT

Thermodynamic Gap

Consuming 300 to 750 kcal below TDEE forces the body to burn ~0.5 to 1.5 lbs of fat per week.

Why Static Deficit Calculators Cause Plateaus

Standard online calculators give you a one-time number on Day 1. However, as your body mass drops, your BMR decreases and your spontaneous movement (NEAT) unconsciously declines. What was a 500-calorie deficit in Week 1 can become maintenance by Week 8.

AdapTDEE solves this by continuously smoothing daily weigh-ins and calorie logs, updating your deficit in real time as your metabolism shifts.