Stride Length Gait & Speed Calculator
Measure the stride length and estimate hip height from a trackway, and see the gait classification and estimated speed, using the equation ichnologists use to read speed from fossil and modern trackways alike.
Estimated gait & speed
Based on R. McNeill Alexander’s 1976 trackway-speed equation, the standard method for estimating speed from stride length in both modern tracking and dinosaur ichnology. An estimate, not a measurement — a changing pace mid-stride or a rough hip-height guess both add error.
How gait and speed are read from a trackway
The key ratio is the relative stride length— stride length divided by hip height. Animals of very different sizes that move at the same relative pace (the same fraction of a stride relative to their own leg length) are said to be “dynamically similar,” and this ratio is what actually determines whether a trackway reads as a walk, trot, or run, independent of the animal’s absolute size. A relative stride length under 2.0 reads as a walk, 2.0 up to 2.9 as a trot, and 2.9 or above as a run.
The speed itself scales with stride length raised to the power 1.67 and hip height raised to the power −1.17 — a relationship Alexander derived so that the same formula works across animals from a small bird to a large dinosaur.
Frequently Asked Questions
What counts as a 'stride' versus a 'step'?
A step is the distance from one foot's print to the very next print of the OTHER foot. A stride is the distance between two successive prints of the SAME foot — one complete cycle of that leg. This calculator needs the stride length, which is typically close to double the step length in a steady, even gait.
How do I estimate hip height from a trackway?
Hip height approximates the track-maker's leg length, measured from the ground to the hip joint. For living animals this is usually estimated from the animal's known shoulder or hip height for its species. In ichnology (fossil trackways) it's commonly approximated as around four times the footprint length for many trackmakers, though this ratio varies by animal and is itself an estimate.
Where does this formula come from?
It's R. McNeill Alexander's 1976 equation (published in Nature) for estimating an animal's speed from its stride length and hip height, based on dynamic similarity between animals of different sizes. It was developed for estimating dinosaur speeds from fossil trackways and remains the standard method in ichnology, and the same relative-stride-length logic is used to read gait from modern animal tracks.
Educational tool only. Real trackways are messy — a partial print, a changing pace mid-stride, or a rough hip-height guess all add error to the estimate.