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For Engineers · Rocket Equation

Rocket Equation for a model rocket

Built for engineers using it for real design work. Go from concept to a running model in the browser, then scale to the cloud when needed. Simulate a model rocket live below — adjust the inputs and watch it respond, right in your browser.

Rocket Equation (Tsiolkovsky)Live

the tyranny of the rocket equation

Controls

Presets

Specific impulse Isp (s)

Mass ratio m₀/mf per stage

Number of stages

Δv = Isp·g·ln(m₀/mf). Because Δv grows only with the log of the mass ratio, reaching orbit (~9.4 km/s) demands enormous propellant fractions — which is exactly why rockets stage.

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Data Inspector

Exhaust velocity2.94 km/s

Δv per stage4.74 km/s

Total Δv4.74 km/s

Reaches LEO?no

Governing equation

Δ v = v_{e} ln \frac{m _{0}}{m _{f}} = I_{s p} g_{0} ln \frac{m _{0}}{m _{f}} = 300 \cdot 9.81 \cdot ln 5 = 4.74 km/s

Reading this result: Short of orbit by 4.7 km/s. Because Δv scales only with ln(mass ratio), raise Isp, lift the mass ratio, or add a stage rather than just adding propellant.

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Frequently asked questions

Is this good for engineers?: Yes — this version of "Rocket Equation for a model rocket" is framed for engineers using it for real design work. Go from concept to a running model in the browser, then scale to the cloud when needed.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.