Hohmann Transfer Delta-V Calculator
A Hohmann transfer is the standard, most fuel-efficient two-burn route between two circular orbits in the same plane. The spacecraft fires once to enter an elliptical transfer orbit, coasts halfway around, then fires again to settle into the target orbit. This calculator takes the starting orbit radius, the target orbit radius, and the central body's gravitational parameter, then returns each burn's delta-v, the total delta-v, and the transfer time. Radii are measured from the center of the central body, and the gravitational parameter is a user-editable input so you can model Earth, the Sun, or any other body.
Hohmann transfer formula
v1 = sqrt(mu / r1), v2 = sqrt(mu / r2)
a = (r1 + r2) / 2 (transfer ellipse semi-major axis)
vp = sqrt(mu * (2/r1 - 1/a)) at perigee
va = sqrt(mu * (2/r2 - 1/a)) at apogee
dv1 = |vp - v1|, dv2 = |v2 - va|
transfer time = pi * sqrt(a^3 / mu)
The first burn changes the circular speed at r1 to the transfer-orbit perigee speed; the second burn changes the transfer-orbit apogee speed to the circular speed at r2. The total is the sum of both burn magnitudes.
Usage notes
- Radii are from the central body's center: orbital radius equals planet radius plus altitude.
- Use consistent units: km for radii and km cubed per second squared for mu.
- The default values model a low Earth orbit to geostationary transfer.
- For very large radius ratios a bi-elliptic transfer can use less delta-v.
- This assumes circular, coplanar orbits and impulsive burns.
Hohmann transfer: frequently asked questions
What is a Hohmann transfer?
A Hohmann transfer is the most fuel-efficient two-burn maneuver between two circular, coplanar orbits. The first burn raises the spacecraft onto an elliptical transfer orbit that touches both the starting and target radii; the second burn at the far side circularizes it at the new orbit. It is the classic minimum-energy transfer for two impulses.
What gravitational parameter should I use?
The standard gravitational parameter mu equals G times the mass of the central body. For Earth it is about 398,600 cubic kilometers per second squared; for the Sun it is about 132,712,000,000. Mu is a user-editable input so you can model transfers around any body using the published value.
Are the orbit radii measured from the center or the surface?
From the center of the central body. For an Earth orbit, add Earth's radius (about 6,378 km) to the altitude above the surface to get the orbital radius. Use consistent kilometer units for both radii and for mu in km cubed per second squared.
Does a Hohmann transfer work for any two orbits?
It is exact for two circular, coplanar orbits. For changes in inclination, eccentric orbits, or very large radius ratios, other transfers such as a bi-elliptic transfer can be more efficient. This calculator covers the standard circular-to-circular case.
What is delta-v?
Delta-v is the change in velocity a maneuver requires, in kilometers per second. It is the standard currency of orbital maneuvers because it maps directly to propellant through the rocket equation. The total here is the sum of the two burn magnitudes.
Official sources
- NASA Glenn Beginner's Guide to Aeronautics: orbital mechanics fundamentals.
- NASA Jet Propulsion Laboratory: Solar System Dynamics constants.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.