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KSP Delta V Calculator

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The Kerbal Space Program (KSP) Delta V Calculator is a practical tool designed for players of the popular space flight simulation game, Kerbal Space Program. In KSP, players build and manage their own space missions, including designing rockets and planning orbital maneuvers. The calculator provides essential calculations that help determine how much change in velocity, or delta-v (Δv), a spacecraft has available for these maneuvers based on the spacecraft's design.

Purpose and Functionality of the KSP Delta V Calculator

Delta-v is a crucial concept in rocket science, representing the total 'budget' of velocity change a spacecraft can achieve with its current fuel and engine configuration. Calculating delta-v accurately is fundamental for mission planning in KSP, as it influences critical decisions like how far a rocket can travel or whether it can achieve orbit.

The Delta V Calculator uses the Tsiolkovsky rocket equation, a fundamental principle in astrodynamics, to determine the delta-v. The equation is:



  • Isp​ is the specific impulse of the engine (efficiency in seconds).
  • 0g0​ is the standard acceleration due to gravity (9.81 m/s²).
  • ln⁡ln represents the natural logarithm.
  • minitial​ is the spacecraft's initial total mass, including fuel.
  • mfinal​ is the mass of the spacecraft after all the fuel is used.

Step-by-Step Example

Let's use the KSP Delta V Calculator with an example:

1. Gather Input Values:

  • Specific Impulse (Isp): 300 seconds
  • Initial Mass (m_initial): 10,000 kg (including fuel)
  • Final Mass (m_final): 6,000 kg (after fuel is burned)

2. Calculate the Mass Ratio:

  • Mass ratio = 10,000 kg6,000 kg6,000kg10,000kg​ ≈ 1.667

3. Compute the Natural Logarithm:

  • ln⁡(1.667)ln(1.667) ≈ 0.511

4. Calculate Delta-v:

  • Δ=300 s×9.81 m/s2×0.511Δv=300s×9.81m/s2×0.511 ≈ 1502.7 m/s

Relevant Information Table

Here's a table displaying different scenarios and their outcomes using the calculator:

Specific Impulse (Isp)Initial Mass (kg)Final Mass (kg)Delta-v (m/s)


The KSP Delta V Calculator is an indispensable tool for players engaged in the strategic planning of space missions in Kerbal Space Program. By providing accurate measurements of the spacecraft's capability to change velocity, it enables better mission design, efficient fuel management, and successful completion of objectives like reaching orbit or traveling to other celestial bodies. The calculator not only enhances gameplay but also brings a deeper understanding of the practical challenges faced in real-world rocketry.

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