What this tool does
The tool estimates TDEE, subtracts your percent, and reports the calorie target, the daily gap, and a rough weekly kilogram change using ~7,700 kcal per kg. If the cut would fall under the educational floor, intake is raised and flagged.
How it works
Same energy engine as the calorie calculator: Mifflin-St Jeor, activity factor, then target = TDEE × (1 − deficit%). Weekly change ≈ daily gap × 7 / 7,700. Hall’s work is why that weekly figure is labeled rough — adaptation and mixed tissue loss mean the scale will not obey a straight line.
Formula and methodology
TDEE = Mifflin-St Jeor BMR × activity. Target = TDEE × (1 − deficit%/100), floored at 1,200 kcal (female) or 1,500 kcal (male). Rough kg/week ≈ (TDEE − target) / (7,700/7). The 7,700 kcal/kg (≈3,500 kcal/lb) rule is a classroom shortcut, not a contract.
How to interpret the result
A 10% cut is a nudge. A 25% cut is aggressive and more likely to wreck training and NEAT. If the floor triggered, you asked for more deficit than this page will print. Protein should rise toward the deficit band on the protein calculator.
Example
TDEE 2,760 kcal with a 20% deficit → about 2,210 kcal, a ~550 kcal gap, very roughly 0.5 kg/week on paper. Real weeks wander with sodium, glycogen, and menstrual cycle. Two weeks of averages beat any single Wednesday.
Common mistakes
- Stacking a 25% food cut on top of a new 12,000-step habit that was not in TDEE — double counting the gap.
- Dropping another 300 kcal the first time the scale holds water.
- Ignoring protein and losing more performance than fat.
- Using the weekly kg line as a bet you must “win.”
When this estimate may be off
- Activity was overstated, so TDEE was fantasy.
- You already lost a lot of weight and the old TDEE is stale.
- Medications, edema, or cycle-related water swamp the weekly signal.
- Intake logging misses oils and weekend alcohol.