One step count, two calculators, two different behaviors
10,000 steps at a 76cm stride covers a real 7.6 km — a figure with no bodyweight input at all. The same 10,000 steps for a 70kg person burns a real 350 kcal; for a 90kg person, the identical 10,000 steps burns 450 kcal instead — 100 kcal more, purely from the extra 20kg.
Why weight changes one answer but not the other
Distance is pure geometry: a step covers however much ground a stride length dictates, regardless of who's taking it. Calories burned is a measure of energy expenditure — and moving more body mass the same distance genuinely does take proportionally more energy, which is exactly why bodyweight is baked directly into the calorie formula but has no place in the distance formula at all.
What this confirms about the two formulas
Neither formula is "wrong" for not including a factor the other one has — they're modeling genuinely different physical quantities. Distance depends only on stride mechanics; calorie burn depends on the energy cost of moving a specific body mass that distance.
A practical takeaway for two people walking together
Two people of very different weights walking the same 10,000 steps side by side cover the identical distance, but burn meaningfully different calorie totals — a useful reminder that step count and distance are shared, shared experiences, while calories burned is genuinely personal to each walker's body.