Weight Loss Calculator Formula

Understand the math behind the weight loss calculator. Each variable explained with a worked example.

Use the Weight Loss Calculator

Formulas Used

Weight Loss per Week

lbs_per_week = deficit_per_day * 7 / 3500

Total Weight Loss

total_loss = deficit_per_day * 7 / 3500 * weeks

Total Weight Loss (kg)

total_loss_kg = deficit_per_day * 7 / 3500 * weeks * 0.453592

Weekly Deficit

weekly_deficit = deficit_per_day * 7

Variables

VariableDescriptionDefault
deficit_per_dayDaily Caloric Deficit(cal)500
weeksTime Period(weeks)12

How It Works

Weight Loss Calculation

Pounds per week = (Daily Deficit x 7) / 3,500

Approximately 3,500 calories equals one pound of body fat.

Safe Weight Loss Rates

| Deficit | Loss/Week | |---|---| | 250 cal/day | 0.5 lbs | | 500 cal/day | 1.0 lbs | | 750 cal/day | 1.5 lbs | | 1000 cal/day | 2.0 lbs |

A deficit of 500-1000 cal/day is generally considered safe.

Worked Example

A 500 calorie daily deficit over 12 weeks.

deficit_per_day = 500weeks = 12
  1. 01Weekly deficit = 500 x 7 = 3,500 cal
  2. 02Loss per week = 3,500 / 3,500 = 1.0 lb/week
  3. 03Total loss = 1.0 x 12 = 12.0 lbs
  4. 04In kg = 12.0 x 0.454 = 5.4 kg

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