What this calculator does
Jurisdiction: Japan. This tool reproduces the Japanese real-estate advertising standard for "minutes on foot" (romanized: toho shoyo jikan). Under the Japanese Fair Competition Code for real estate advertising, walking distance is advertised at a fixed rate of 1 minute = 80 meters, with any fraction of a minute rounded up. Enter the advertised walking time, and this calculator returns the corresponding walking distance in meters and kilometers. The 80 m/min default is the Japan-specific assumption; conventions differ in other countries, so non-Japanese users should treat the result as an estimate.
How to use it
Enter the "minutes on foot" figure from a property listing into Walking time. Leave Walking speed at 80 m/min to match the Japanese standard (about 4.8 km/h), or change it to model a slower or faster walker. The result is the maximum distance consistent with that advertised figure, because advertised minutes are themselves already rounded up from the true walking time.
The formula
The math is direct: distance in meters equals minutes times speed, since meters-per-minute multiplied by minutes yields meters with no unit conversion. Kilometers are simply meters divided by 1000. The inverse rule used by Japanese ads is minutes = ceil(distance / 80) — rounding up any partial minute.
$$\text{Distance (m)} = \text{Time (min)} \times \text{Speed (m/min)}$$
Worked example
For "12 minutes on foot" at 80 m/min:
$$12 \times 80 = 960 \text{ m}$$
which is 0.96 km. With a custom slower speed of 70 m/min for 5 minutes:
$$5 \times 70 = 350 \text{ m} = 0.35 \text{ km}$$
FAQ
Is this straight-line distance? No. The Japanese standard measures distance along the road or walking path (romanized: michinori), to the nearest point of the property — not as the crow flies.
Does it include waiting time? No. Time spent waiting at traffic lights and railway crossings is not counted in the advertised figure.
Why is the distance the maximum? Because advertised minutes are rounded up, "12 minutes" could correspond to a true time anywhere just above 11 minutes up to 12 minutes, so 960 m is the upper bound for that label.
