What this tool does
Same structure as the weight-loss tool, inverted: goal weight above current, weekly gain between 0.1 and 0.4 kg, surplus capped near 20% of TDEE, week count from the gap. Height and current weight come from the unit toggle; goal pounds are available in imperial.
How it works
Desired daily surplus ≈ weekly kg × 7,700 / 7, expressed as a percent of TDEE and capped. Target calories are TDEE plus that surplus. Without progressive lifting, the timeline still “works” on the scale — you will just gain a larger fat share.
Formula and methodology
TDEE = Mifflin-St Jeor BMR × activity. Surplus kcal/day ≈ weeklyKg × 7700 / 7, capped near 20% of TDEE. Weeks ≈ |goalKg − weight| / weeklyKg. Weekly gain is clamped to 0.1–0.4 kg so the form cannot request a 1 kg/week “bulk.”
How to interpret the result
Going from 70 to 74 kg at 0.2 kg/week is about 20 weeks of boring eating. If the waist races ahead of the bar, slow the weekly kg. Protein stays in the muscle band the whole time, including rest days.
Example
72 kg toward 76 kg at 0.2 kg/week ≈ 20 weeks. If TDEE is 2,400 kcal, that pace is a small daily surplus — extra milk in coffee and a larger rice scoop, not a second dessert identity. Re-run when the weekly average actually sits near 76 kg.
Common mistakes
- Goal weight 15 kg up with a 0.4 kg/week cap and surprise that it takes most of a year.
- Eating the surplus without a training log.
- Force-feeding past fullness every night because the week count felt like a dare.
- Cutting cardio to zero when walks were part of sanity, then blaming the calculator for restlessness.
When this estimate may be off
- You are returning from illness or under-eating; catch-up weight is not this model.
- Creatine, glycogen, or a new menstrual cycle swamp early scale jumps.
- Goal weight is a guess copied from a heavier friend.
- TDEE already assumed “very active” and the surplus stacks on phantom training.