Rally Stage Speed Calculator

Rally stages are run against a target time rather than judged purely on top speed, so the first thing this calculator does is the basic pace conversion: required average speed in km/h equals stage distance divided by target time, scaled from minutes to hours by multiplying by 60. It also reports that same relationship inverted as pace in minutes per kilometer, and estimates a maximum allowed time before time-control penalties as your target time plus a flat 50% buffer, which is a rule-of-thumb margin rather than a rule pulled from any specific rally's actual regulations. Surface type feeds into a difficulty adjustment: tarmac is the baseline (factor 1.0), gravel is treated as 15% slower (factor 0.85), and snow/ice as 30% slower (factor 0.70), reflecting that the same average speed demands more from a car and driver as grip drops.

The surface speed adjustment shown is how much additional "effective" speed your required pace represents once you divide out that surface factor — i.e., how hard your target pace actually is to achieve given the surface, not a speed you should literally target. Difficulty rating on a 1-10 scale is a simple linear mapping of that surface-adjusted effective speed against reference thresholds (120 km/h for tarmac, 100 for gravel, 80 for snow, each corresponding to a rating of about 8), clamped to stay within 1 and 10. Treat all of this as a planning heuristic built from generic percentage rules of thumb, not stage-specific telemetry — actual required pace depends heavily on corner count, elevation change, and visibility that a distance-and-time input alone can't capture.