Work out weight loss goal date instantly with clear inputs, formula shown and shareable results.
One kilogram of body fat stores roughly 7700 kcal, so losing 0.6 kg a week needs a deficit of about 660 kcal a day. Going from 90 kg to 78 kg means 12 kg, or 20 weeks at that rate. Real loss slows as weight falls because maintenance energy needs drop, so the later weeks usually take longer than the projection.
Weeks required
weeks = weight to lose / weekly rate
Daily deficit
deficit = weekly rate x 7700 / 7 kcal
These figures are population-average estimates, not a medical assessment or diagnosis. Body composition equations carry errors of several percentage points, and healthy ranges vary with age, ethnicity, muscularity and medical history. Discuss weight or body composition goals with a qualified clinician or dietitian.
It is the energy content of a kilogram of adipose tissue, allowing for its roughly 87% fat content at 9 kcal per gram.
A lighter body burns less at rest and in movement, so the same intake becomes a smaller deficit. Recalculating every 5 kg keeps the plan honest.