Understand the key differences between driving distance and straight-line distance, why they differ, and when each measurement matters.
Straight-line distance (also called great-circle or as-the-crow-flies distance) measures the shortest path between two points on Earth. Driving distance follows real roads, which adds detours, terrain, and traffic.
On average, driving distance is about 1.3× longer than straight-line distance, but the multiplier varies dramatically with geography. Mountain regions, islands, and dense road networks can push it much higher.
This guide explains why the two values differ, when each one matters, and how to convert between them for everyday travel planning.