# How do you calculate thrust produced by a rocket engine?

I was planning on building a water-powered rocket. I also wanted to know how high my rocket might go. Could someone help me figure out, how to calculate thrust produced by a rocket engine?

• By water powered, do you mean a rocket where compressed air pushes water out? Start by calculating the energy in the compressed air at the instant of launch. A fraction of this potential energy is what is present in the rocket when it reaches peak altitude. There will be a lot of losses also which will bring down the peak altitude from the value arrived at using the energy method.
– AJN
Nov 24, 2021 at 0:35
• @AJN Yes, a rocket in which compressed air pushes it water out. Can you please use some numericals in the rocket equation? Thank you in advance Nov 24, 2021 at 0:58
• You have provided no numerical data in your question. Nov 24, 2021 at 18:31

If you know the mass flow rate q and the exhaust velocity v, the thrust f is the product of q and v.

If the engine is running in a test stand, measurement of the thrust might be easier than to measure both mass flow rate and exhaust velocity.

For the measurement of thrust look at this question.