Weight Loss Calculator

Clinical Energy Balance & Mifflin-St Jeor Formulation

Sustainable fat loss requires creating a steady negative energy balance while consuming adequate dietary protein to prevent muscle loss:

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• Basal Metabolic Rate (BMR) — Mifflin-St Jeor Equation**:

Men: BMR = (10 × W_kg) + (6.25 × H_cm) - (5 × Age) + 5

Women: BMR = (10 × W_kg) + (6.25 × H_cm) - (5 × Age) - 161

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• Total Daily Energy Expenditure (TDEE)**:

TDEE = BMR × Physical Activity Multiplier

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• Calorie Deficit vs Weekly Fat Loss**:

• 0.5 lb/week loss: -250 kcal/day deficit (Gentle & highly sustainable)

• 1.0 lb/week loss: -500 kcal/day deficit (Clinical gold-standard recommendation)

• 1.5 lbs/week loss: -750 kcal/day deficit (Aggressive cut)

• 2.0 lbs/week loss: -1,000 kcal/day deficit (Maximum safe rate)

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• Caloric Safety Floors**: Never consume below 1,500 kcal/day for men or 1,200 kcal/day for women without direct physician supervision to prevent micronutrient deficiencies, hair loss, and thyroid down-regulation.

How to Use This Calculator

Enter your Unit System — select from Imperial (lbs, inches), Metric (kg, cm), Biological Sex — select from Male, Female, Age (Years) (e.g. 32), Current Body Weight (e.g. 190), Height (inches or cm) (e.g. 70 for 5'10" or 178 cm), Goal Target Weight (e.g. 170), Physical Activity Level — select from Sedentary (Desk job, minimal exercise), Lightly Active (1–3 exercise sessions/week), Moderately Active (3–5 exercise sessions/week), Target Weight Loss Pace — select from 0.5 lb / week (Mild -250 kcal/day deficit - Highly Sustainable), 1.0 lb / week (Standard -500 kcal/day deficit - Recommended), 1.5 lbs / week (Aggressive -750 kcal/day deficit), and Weight Loss Strategy Benchmark — select from Custom Goals, Standard Loss (190 lbs → 170 lbs / -20 lbs @ 1.0 lb/wk / 20 Weeks / 1,848 kcal), Aggressive Cut (220 lbs → 180 lbs / -40 lbs @ 2.0 lbs/wk / 20 Weeks / 1,600 kcal). Results update instantly — no submit button needed. Use metric or imperial units as labeled. For the most accurate result, measure height and weight in the morning without shoes.

The Formula

Conversion factors (to SI base unit or reference unit):

curr: 190.0

ht: 70.0

goal: 170.0

act: 1.375

pace: 1.0

Worked Example

A 190 lb male with a maintenance TDEE of 2,348 kcal eats 1,848 kcal/day (-500 kcal deficit), losing exactly 1.0 lb per week and successfully reaching his 170 lb goal in 20 weeks.

Understanding Your Result

Health calculations based on standard clinical formulas give a population-reference estimate — individual variation exists. Compare your result to the reference ranges provided using validated sources (WHO, CDC, NIH, or specialty clinical guidelines). A single measurement is a starting point; meaningful health trends emerge from tracking the same metric over time under consistent conditions. For values outside reference ranges, consult a qualified healthcare provider before making changes to diet, exercise, or medication.