RC Motor & Speed Calculator
Compare motors side by side, calculate RPM and top speed, or figure out your gear ratio. All the math, none of the guesswork.
Motor 1
Motor 2
Turn-to-KV is an estimate. This calculator uses about 47,000 divided by turns, a midpoint between budget 540 stock motors near 42,000 and hotter stock motors near 53,000. The same turn count can land about 15% either side of the figure shown.
Comparison Results
| Metric | Motor 1 | Motor 2 | Advantage |
|---|
Visual Comparison
Motor 1 — Best For:
Motor 2 — Best For:
Quick Presets
Estimated Top Speed Calculator
Enter your motor, battery, gearing, and tire size to estimate theoretical top speed. Real-world speed will be lower due to rolling resistance, drag, and drivetrain losses.
About This Estimate
This is the theoretical maximum assuming no losses. Real-world speed is typically 70-85% of theoretical due to drivetrain friction, aerodynamic drag, rolling resistance, and motor efficiency under load. For geared vehicles (like most buggies and trucks with a transmission), make sure to include the internal gear ratio.
Common Tire Diameters
Motor RPM Calculator
Calculate no-load RPM for any motor and battery combination. Enter KV rating or motor turns.
The turns field uses the same estimate: about 47,000 divided by turns. Real stock motors vary by roughly 15%.
RPM at Different Voltages
Results for --
Estimated Wattage
Rough power estimates based on typical current draw for this KV range. Actual wattage depends on ESC, load, and motor efficiency.
Gear Ratio Calculator
Calculate your final drive ratio and see how pinion/spur changes affect it. A lower ratio means more top speed and less torque. A higher ratio means more torque and acceleration, and less top speed.
Pinion Swap Chart
See how changing pinion size affects your ratio with the same spur gear.
| Pinion | Ext. Ratio | Final Ratio | Change | Effect |
|---|