Created By : Vaibhavi Kumari

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 07, 2023

The Rocket Equation Calculator is a free tool that calculates the change in velocity based on input parameters such as exhaust velocity, starting, and end mass of rockets, and so on. This free application will make your computations easier, and the results will appear in a flash.

Choose a Calculation
Effective exhaust velocity
Initial mass
Final mass:

What is meant by Rocket Equation?

Rocket Equation describes the motion of a device that applies acceleration to themselves using thrust. It describes the relationship between velocity of rocket, exhaust velocity, mass. We can use the Rocket Equation in simple cases when no other external forces act on it.

How to find Change in Velocity?

Follow the simple guidelines provided below to determine the change in velocity using Rocket Equation. They are as such

  • Firstly, determine the exhaust velocity, initial mass, final mass.
  • Then, simply input the known parameters in the formula to find the change in velocity i.e. Δv = ve * ln(m0 / mf).
  • On simplification you will get the change in velocity.

Rocket Equation Formula

Velocity of Rocket can be found using the formula

Δv = ve * ln(m0 / mf)

In which Δv stands for Change of Velocity

ve is effective exhaust velocity

m0 is the initial mass including rocket weight and propellants

mf is the final mass including rocket weight without propellants

Δv is the difference between final and initial velocity

Greater the ve and m0 the higher velocities you can get.


If the effective exhaust velocity is 5,400 km/h, initial mass is 45 t, final mass is 20 t calculate the change in velocity?


Given that

Effective Exhaust Velocity = 5,400

Initial Mass = 45 t

Final Mass = 20 t

We know formula for Change in Velocity Δv = ve * ln(m0 / mf)

Substitute the input values in the formula Δv = 5400 * ln(45 / 20)

On simplification we get change in velocity Δv = 1.2164 km/s

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Multistage Rocket Equation Formula

During the motion of the rocket many parts are rejected one after the other. For suppose a part runs out of fuel it becomes redundant mass and needs to be removed. Change of velocity can be found independently for every step and then linearly sum up Δv = Δv1 + Δv2 + .... One Advantage of using this is we can employ a different type of rocket engine tuned for different conditions.

FAQs on Rocket Equation

1. Why is the Tsiolkovsky rocket equation referred to as an ideal rocket equation?

When no external forces are acting on the rocket, the Tsiolkovsky rocket equation can be employed. As a result, it's referred to as an ideal rocket equation or a classic rocket equation.

2. What Can We Learn from the Rocket Equation?

The Rocket Equation is a mathematical equation that defines the motion of vehicles that operate on the rocket principle, that is, devices that can accelerate themselves by thrust.

3. How much thrust is required by a rocket?

To do so, it must generate 3.5 million kilos (7.2 million pounds) of thrust! The shuttle becomes lighter as the fuel burns, and less effort is required to propel it upward, so it accelerates!

4. In a rocket, how do you measure trust?

Strain gauge load cells are used to measure thrust, and they are calibrated in place using a separate transfer standard strain gauge load cell or a dead weight. The flow rate of propellant is usually measured with volumetric or mass flow metres.

5. What is the fuel consumption of a rocket?

The two Solid Rocket Boosters burn 11,000 pounds of fuel per second during liftoff. That's two million times the rate at which the average family automobile consumes petrol.