Geographic radius calculations
A circular map radius of distance r encloses an area A = π × r² and perimeter circumference C = 2 × π × r.
Land coverage translates across units: 1 square kilometre = 100 hectares ≈ 247.1 acres. 1 square mile = 640 acres.
Estimated transit times assume nominal travel speeds: walking at 5 km/h (3.1 mph), cycling at 18 km/h (11.2 mph), and suburban driving at 50 km/h (31.1 mph).
Worked example: 5-kilometre delivery radius
A 5 km radius service zone encloses an area of π × 5² = 78.54 km² (30.32 sq miles or 19,407 acres) with a 31.42 km perimeter.
Travel time to the outer perimeter is approximately 60 minutes walking or 6 minutes driving.
Map radius inputs
Radius Distance
Radial distance from center point in your chosen unit.
CALCULATOR QUESTIONS
Geographic radius & coverage calculator questions
How big is a 5-mile radius circle?
A 5-mile radius encloses approximately 78.54 square miles, equivalent to 50,265 acres or 203.4 square kilometres.
How is walking time to perimeter calculated?
Walking time assumes a standard average pedestrian pace of 5 km/h (3.1 mph).