Fun tools reuse the same deterministic engines as the serious lab pages, then ask shareable questions. Marathon steps multiply a stride across 42.195 km. One-hour distance inverts pace. Marathon and famous-distance equivalents rescale any kilometre total.
Playlist and song counters compare run duration to music length. Elite comparison pages use a small documented reference table, not a live results database. Lifetime distance scales weekly volume across years.
Tone can be lighter here. The arithmetic and citations stay honest, and every page links back into pace, volume, cadence, or race tools when you want the serious answer.