Transit Catchment Calculator
The population within walking distance of a station or stop — from the walk time people will accept, their walking speed, the street network detour, and the density around it.
A ten-minute walk at 80 meters a minute is 800 meters as the crow flies.
How the transit catchment calculator works
A ten-minute walk at 80 meters a minute is 800 meters as the crow flies. But streets do not run as the crow flies: the real reach is the straight-line distance divided by a detour factor, typically 1.2 to 1.4.
The catchment is a circle of that reduced radius, and the population inside it is that area times the density. Everything hangs on the detour factor, which is why grid streets serve transit so much better than cul-de-sacs.
Formula: radius = walk time × speed / detour; catchment = π r² × density
Worked examples
| Inputs | People in the catchment | Note |
|---|---|---|
| Ten minutes at 45 per ha | 5,354 | about 5,400 people |
| A grid street pattern | 6,283 | a larger catchment |
| Higher density | 14,277 | the same walk, three times the people |
FAQFrequently asked questions
How far will people walk to transit?
About 400 m to a bus stop and 800 m to a station — five and ten minutes. Beyond that ridership falls off steeply.
What is a detour factor?
How much longer the walk along streets is than the straight line. A grid is about 1.2; a cul-de-sac suburb can exceed 1.6.
Why does the street pattern matter so much?
Because the catchment is a circle whose radius shrinks with the detour, and area goes with the square. A 1.6 detour cuts the catchment to about half that of a 1.2 grid.
What density supports a station?
The catchment population divided by the walk radius says it: 5,000 in the 800 m circle is marginal, 15,000 is comfortable.
Does this account for barriers?
Only through the detour factor. A railway line, a highway or a river on one side can halve the real catchment.
Where these figures come from
- UN-Habitat — Urban Indicators Guidelines — density, green space and public space benchmarks
- World Health Organization — Urban green spaces — the 9 m² per person minimum
- ITE — Parking Generation Manual — parking demand rates by land use
- US Census Bureau — Population and housing — the US national statistics agency
Last checked: September 2026. Default per-capita rates are mid-range figures from national statistical agencies and utility reports; every one is an input you should replace with the local figure.