RC Car Speed Calculator

The RC Car Speed Calculator is a quick planning tool for estimating how fast an RC car may run from the basic setup numbers. It is intended for hobbyists who want a fast answer from motor Kv, cell count, gear ratio, tire diameter, and loaded RPM assumptions without building a full speed-run model.

What this calculator does

The calculator is useful for brushless electric cars, buggies, touring cars, bashers, and simple nitro or gas speed estimates. Real speed depends on voltage sag, tire growth, aerodynamic drag, surface grip, motor load, and how much RPM the vehicle can actually pull under load, so the result should be treated as a setup estimate rather than a guaranteed GPS number. Use it by entering your drivetrain values and comparing a few gear or tire changes. Example: if a 4S car gains very little estimated speed from a larger pinion, that may be a sign that the motor and battery will work harder without a worthwhile real-world improvement.

In practical terms: It turns common RC car setup values into a quick speed estimate for electric and nitro or gas models.

How to use it

Enter motor Kv or loaded RPM, voltage or cell count, gear ratio, and tire diameter. Compare multiple gearing and tire combinations before testing.

Example calculation

Use it to estimate whether changing from a 20-tooth to a 24-tooth pinion is likely to increase speed enough to justify the higher load.