What KV means
KV is the motor's velocity constant: theoretical revolutions per minute per volt applied. A 2300 KV motor on 14.8 V has a theoretical no-load speed of 2300 × 14.8 = 34,040 RPM.
Why "theoretical"
The number assumes the motor spins freely. Under real load the RPM drops because of propeller or wheel load, battery voltage sag and motor efficiency. KV alone never tells you real speed or power.
Choosing KV
Higher KV means more RPM per volt — more speed on paper, more current and heat for the same setup. Lower KV motors suit heavier loads or higher cell counts. Always sanity-check KV × pack voltage against your ESC and gearing.
Where it is used
The Motor KV RPM Calculator computes the no-load figure; the Car Speed Calculator chains it through gearing to a theoretical speed.