Leonardo da Vinci designed an odometer to record the distance traveled by a cart.
His cart-based odometer used a wheel connected to a counting mechanism. As the wheel turned, gears advanced a display or container by fixed increments. In one described design, the mechanism released a small object after a set number of wheel rotations, allowing the traveled distance to be counted.
The device belongs to Leonardo’s work on surveying, mapping, and military engineering. Accurate distance measurement was valuable for planning roads, fortifications, canals, and battle movements. A wheel-based counter also offered a practical way to measure terrain without repeatedly using a chain or rope.
Leonardo did not invent the basic idea of an odometer; ancient Greek and Roman engineers had used distance-measuring devices. His importance lies in the detailed mechanical design and its connection to Renaissance field measurement. An odometer measures distance, whereas a speedometer measures speed.