Hohmann Transfer Calculator
The two burns of a Hohmann transfer between circular orbits — each delta-v, the total, and the transfer time — for any body, with low Earth orbit to geostationary as the worked default.
The cheapest way between two circular orbits is an ellipse touching both: one burn at the low orbit to raise the far side, a second at the high orbit to circularise.
How the hohmann transfer calculator works
The cheapest way between two circular orbits is an ellipse touching both: one burn at the low orbit to raise the far side, a second at the high orbit to circularise. Each burn is the difference between the speed you have and the speed the next orbit needs.
Low Earth orbit to geostationary costs about 3.9 km/s and takes five and a quarter hours — the outbound half of the transfer ellipse. Coming down is the same numbers, fired the other way.
Formula: Δv₁ = √(μ/r₁) (√(2r₂/(r₁+r₂)) − 1); Δv₂ = √(μ/r₂) (1 − √(2r₁/(r₁+r₂))); t = π √(((r₁+r₂)/2)³ / μ)
Worked examples
| Inputs | Total delta-v (km/s) | Note |
|---|---|---|
| LEO to geostationary | 3.8566 | 3.86 km/s, 5.3 hours |
| Coming back down | 3.8566 | the same, retrograde |
| Low lunar orbit to 1,000 km | 0.2923 | a small burn |
FAQFrequently asked questions
What is a Hohmann transfer?
The minimum-energy two-burn path between two circular orbits, using an ellipse that touches both. Walter Hohmann worked it out in 1925, before there were rockets to fly it.
Why two burns?
The first stretches the circle into an ellipse whose far point reaches the target; the second, at that far point, circularises. Without the second burn you fall back to where you started.
How long does LEO to GEO take?
About 5.3 hours of coasting between burns. Real satellites often spend weeks instead, using small efficient thrusters over many orbits.
Is it always the cheapest?
For ratios of orbit radius under about 11.9. Beyond that a bi-elliptic transfer — going out further first — saves fuel at the cost of much more time.
What GM should I use?
Earth 398,600; Moon 4,903; Mars 42,828; Sun 1.327 × 10¹¹ km³/s². GM is known far more precisely than G and M separately, which is why it is the input.
Where these figures come from
- NIST — CODATA 2018 fundamental physical constants — G and the speed of light
- IAU 2015 Resolution B3 — nominal solar and planetary conversion constants — the astronomical unit, solar mass and planetary radii
- Royal Observatory Greenwich — the historic home of the prime meridian
Last checked: September 2026. Constants are CODATA 2018 (G, c) and IAU 2015 nominal values (solar and planetary parameters).