Your numbers
All inputs persist between visits and carry across to the VO₂ max page.
Typical TK daypack with 2-3 L water at start of day is 5-7 kg. The water depletes through the day; we use the starting weight for the physics calculation, which is realistic.
:
Enables the 5 km pace projection. Race or honest time-trial pace, not a casual jog.
If known. Used to flag muscular climbers where weight loss isn't the right lever.
Your route
Pick the route you're climbing — the physics below adjusts to your specific schedule.
If I lose 5 kg
Drag to set how much weight you'd lose. The numbers below recompute against your selected route.
Enter your weight and height above to see the physics.
What weight to be ready?
Pick a fitness tier (matched to the VO₂ max calculator). We'll show you the target weight that puts you in adequate range for that tier.
Enter your weight and height above to see your target.
Important honest caveats
- The watts/work figures assume Naismith's rule pace (5 km/h flat + 600 m/h vertical) eroded by altitude oxygen availability. Actual TK group pace is deliberately slower for acclimatisation — your real-time watts will be lower, your real-time hours longer.
- Mechanical work (mass × g × height) is what physics says. Real metabolic cost is 4–5× higher because human muscle hill-climbing efficiency is around 20–25%. We show both.
- The 5 km pace projection assumes everything else equal — same training, same heart, same sensible diet. Crash weight loss costs aerobic capacity, so the maths under-reads the true cost of unhealthy weight loss.
- Respiratory water loss figures are typical ranges. Individual variation at altitude is large — some climbers lose far more, especially at low humidity and high minute-ventilation.
- This is not a diet planner. It quantifies the impact of weight loss on the mountain. The "how" is the 12·9 Method (link below in target-weight view).