Nozzle Thrust Calculator

Nozzle Thrust Calculator

A rocket or jet nozzle's thrust comes from two distinct sources: the momentum of the accelerated exhaust mass, and any leftover pressure difference at the nozzle exit compared to the surrounding atmosphere.

The Formula

F = ṁ × V_e + (P_e - P_a) × A_e

Worked Example

50 kg/s of exhaust at 2,500 m/s exit velocity, with exit pressure exactly matching ambient pressure (a perfectly expanded nozzle): F = 50 × 2,500 + 0 = 125,000 N = 125 kN, entirely from momentum thrust.

How to Use This Calculator

1. Enter exhaust mass flow rate and exit velocity.
2. Enter exit pressure and ambient pressure.
3. Enter nozzle exit area.

A perfectly expanded nozzle (exit pressure equals ambient) produces thrust from momentum alone; an under- or over-expanded nozzle adds or subtracts a pressure thrust term on top of that baseline.