Hohmann Transfer Calculator
Two-burn minimum-energy transfer between coplanar circular orbits. Enter departure and arrival altitude to get both burns, total Δv, and transfer time. Earth-centred by default; other central bodies selectable.
Inputs
Central body
Altitudes are measured above the body's mean surface radius (6,371 km).
Orbits
Result
Need plane changes, bi-elliptic comparison, finite-burn losses, or a real launch window?
Sign up →Frequently asked questions
What is a Hohmann transfer?
A two-impulse transfer between coplanar circular orbits using an ellipse tangent to both. The first burn raises apoapsis to the target radius; the second circularises there. For most radius ratios it is the minimum-Δv two-burn solution.
When is a Hohmann transfer NOT optimal?
Above a radius ratio of about 11.94, a bi-elliptic transfer — burning out well past the target, then back down — costs less total Δv despite taking far longer. Between roughly 11.94 and 15.58 it depends on the intermediate apoapsis chosen.
Why does the phase angle matter?
Hitting a target rather than just a radius means departing when the target leads by the right angle. The value here is the lead angle the target must have at ignition so it arrives at apoapsis when you do.
What does this tool NOT account for?
Plane changes, finite-burn gravity losses, J2 drift during transfer, atmospheric drag, third-body effects, or non-circular starting orbits. Those live in the Aerospace Pack's maneuver and propagation tools.
Upgrade for real transfer design
- Bi-elliptic and Lambert transfer solvers
- Combined plane-change optimisation
- Finite-burn gravity loss modelling
- Porkchop plots for interplanetary windows
- Maneuver schedule export to the ops timeline