Hohmann Transfer Calculator
The two burns, total delta-v and travel time to move between two circular orbits.
Results
What this tool does
Moving from one circular orbit to another takes exactly two pushes: one to stretch the orbit into an ellipse that just touches the destination, and one at the far end to circularise it again. In between the spacecraft coasts, engines off, for half the period of the transfer ellipse. The default values here are the classic case — a low parking orbit at 300 km altitude out to geostationary.
Formula
dv1 = √(mu/r1)(√(2r2/(r1+r2)) - 1) ; dv2 = √(mu/r2)(1 - √(2r1/(r1+r2)))
Variables
| Symbol | Meaning | Unit |
|---|---|---|
r1 | Starting orbit radius | km |
r2 | Target orbit radius | km |
mu | Gravitational parameter | km³/s² |
DT | Total delta-v | km/s |
D1 | First burn | km/s |
D2 | Second burn | km/s |
V1 | Orbital velocity | km/s |
TT | Transfer time | h |
Worked example
- Starting orbit radius6678 km
- Target orbit radius42,164 km
- Gravitational parameter398,600 km³/s²
- Total delta-v3.8926 km/s
- First burn2.4258 km/s
- Second burn1.4668 km/s
- Orbital velocity7.7258 km/s
- Transfer time5.2750 h
Limitations
- The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.
- Mixing units is the most common source of error. Convert every input to the units shown next to each field before calculating.
Frequently asked questions
Is the Hohmann transfer always the cheapest?
For two coplanar circular orbits it is the cheapest two-burn transfer, and that covers most real missions. The exception is when the outer orbit is more than about 11.94 times the inner one: past that ratio a bi-elliptic transfer, which goes far out beyond the target and comes back, actually costs less delta-v, at the price of a much longer trip.