Leonardo da Vinci designed an odometer that used gears to count the distance traveled by a cart.
His Renaissance odometer concept was connected to a cart wheel. As the wheel turned, a gear mechanism advanced a counting device, allowing the operator to estimate how far the cart had moved. The design belongs to Leonardo’s broader study of machines, measurement, military engineering, and surveying.
An odometer measures distance, while a speedometer measures speed. Leonardo’s device was not an electronic instrument and did not provide the continuous digital readings found in modern vehicles. Instead, it translated wheel rotation into a mechanical count. Ancient engineers had already explored related measuring devices, so Leonardo’s design is best understood as an important historical mechanism rather than the first odometer ever conceived.