BMI Weight Loss Calculator — Entered Scenarios

BMI = weight (kg) ÷ height (m)². Reference mass = entered BMI reference × height (m)². The reference is a comparison value, not a personal goal, diagnosis or determination of how much weight someone should lose.

The worksheet shows the positive difference between current mass and reference mass, or zero when current mass is at or below the reference. It does not evaluate health, muscle mass, body composition or eligibility for a weight-loss intervention.

The adult arithmetic worksheet accepts BMI references from 18.5–30. This interface range does not certify that any value is appropriate for an individual. A BMI reference of 22 at 170 cm corresponds to 22 × 1.7² = 63.58 kg.

Age 18–100 is retained as an adult worksheet boundary. Sex and activity fields have been removed because this pilot does not calculate resting energy or recommended intake.

The local energy factors are 7,700 kcal/kg in metric mode and 3,500 kcal/lb in imperial mode. They are rounded, separate bookkeeping conventions, not exactly equivalent unit conversions or fixed physiological energy requirements.

Daily energy difference assumption = entered weekly rate × selected energy factor ÷ 7 days/week.

A 0.5 kg/week scenario gives 550 kcal/day; a 1 lb/week scenario gives 500 kcal/day. These results do not prescribe an intake, minimum calorie floor, exercise dose or required deficit.

The rate is explicitly entered in kg/week or lb/week. No automatic conservative, moderate or aggressive recommendation is selected. Changing the rate changes the arithmetic, without establishing safety or achievability.

For 80 kg, 170 cm, BMI reference 22 and entered 0.5 kg/week: reference mass 63.58 kg, difference 16.42 kg. The existing metric convention rounds that difference to 16.4 kg before division; rounding 16.4 ÷ 0.5 upward gives 33 weeks. At 0.25 kg/week it gives 66 weeks and 275 kcal/day.

Duration is the weight difference divided by the entered rate, rounded up to whole weeks. It assumes an unchanged rate throughout. NIDDK describes changing metabolism and energy needs during weight loss, so this static duration is not an individual timeline.

Switching units clears the result and rate so that a previous kg/week entry cannot silently become lb/week. Editing any input clears the stored result.

One international pound is exactly 0.45359237 kg, and one inch is exactly 0.0254 m. BMI is computed in kg and m; mass results convert once to the chosen unit.

For 200 lb, 70 inches and BMI reference 22: reference mass ≈153.3 lb; positive difference ≈46.7 lb. At an entered 1 lb/week, the worksheet rounds the static duration upward to 47 weeks and uses 3,500 ÷ 7 = 500 kcal/day. Metric and imperial energy scenarios use different rounded coefficients.

These arithmetic outputs do not account for pregnancy, childhood, eating disorders, illness, medicines or individual body composition. A zero difference does not mean no health assessment is needed.

• NIST SP 811, 2008: SI conversion factors
• NIDDK: Eating and physical activity — metabolism and changing energy needs
• Hall et al., 2011: dynamic energy balance

Sources accessed and assumptions checked: 2026-09-30. Unit references support conversion; they do not validate personal weight-change predictions or the local static energy factors.