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Rocket Delta V Calculator

Work out rocket delta v instantly with clear inputs, formula shown and shareable results.

About Rocket Delta V Calculator

The Tsiolkovsky rocket equation gives delta-v as exhaust velocity times the natural log of the mass ratio. Burning 380 tonnes of a 500 tonne vehicle at 3000 m/s exhaust velocity yields 4283 m/s. The logarithm is the tyranny of the rocket equation: each additional increment of delta-v costs exponentially more propellant.

Formulas

Tsiolkovsky equation

dv = ve x ln(m0 / mf)

Specific impulse

Isp = ve / g0

Worked example

With the default values below, Rocket Delta V Calculator returns Delta-V Achieved of 4,281.3. Change any input above and every figure here is recalculated in your browser.

Inputs used

Effective exhaust velocityminimum 0 m/s
3,000 m/s
Initial massminimum 0 kg
500,000 kg
Final massminimum 0 kg
120,000 kg

Results

Delta-V Achieved
4,281.3 m/s
Mass Ratio
4.1667
Propellant Consumed
380,000 kg
Equivalent Specific Impulse
305.91 s

Step by step

  1. 1Values used
  2. 2Tsiolkovsky equation
  3. 3Specific impulse
  4. 4Delta-V Achieved= 4,281.3 m/s
  5. 5Mass Ratio= 4.1667
  6. 6Propellant Consumed= 380,000 kg
  7. 7Equivalent Specific Impulse= 305.91 s

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is the relationship logarithmic?

Because propellant must accelerate the propellant still aboard. Each kilogram of payload delta-v demands exponentially more fuel.

How much delta-v does low Earth orbit need?

About 9.4 km/s from the ground including gravity and drag losses, against the 7.8 km/s of orbital velocity itself.

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