Hohmann Transfer Calculator
μ = 398,600.442 km³/s²
Altitude above the body's surface in km (e.g. 400 for ISS-like LEO)
Altitude of the target orbit above the body's surface in km
Enter Orbital Parameters
Select a central body, enter your initial and target orbit radii (or choose a preset), and the calculator will instantly show delta-V burns, transfer time, and orbital velocities.
How to Use the Hohmann Transfer Calculator
Choose your mode and central body
Select 'Between Two Orbits' for satellite transfers around Earth, Moon, Mars, or other bodies. Choose 'Interplanetary' for planet-to-planet transfers. In orbit mode, pick your central body from the dropdown — Earth's gravitational parameter (μ = 398,600 km³/s²) is pre-selected by default.
Enter orbit radii or use a preset
Enter your initial orbit (r₁) and target orbit (r₂). Toggle between 'Altitude above surface' and 'Radius from center' input modes. Alternatively, load a common scenario using the Quick Preset dropdown: LEO to GEO loads 400 km altitude and 35,786 km altitude instantly.
Read delta-V and transfer time results
The results card shows total Δv in both km/s and m/s, the first burn (Δv₁) at departure, and the second burn (Δv₂) at arrival. The stacked bar chart shows their proportions. Transfer time is displayed in days, hours, and minutes. The orbit size comparison bars show the relative scale of r₁, the transfer ellipse semi-major axis, and r₂.
Optionally calculate propellant mass and export
Expand 'Include propellant calculation' and enter spacecraft initial mass (kg) and engine specific impulse (Isp in seconds) to compute propellant consumption via the Tsiolkovsky rocket equation. The donut chart shows propellant fraction vs. dry mass. Click 'Export CSV' to download all computed values or 'Print Results' for a printed summary.
Frequently Asked Questions
What is a Hohmann transfer orbit and why is it fuel-efficient?
A Hohmann transfer is a two-burn orbital maneuver connecting two circular, coplanar orbits via an intermediate ellipse. It is the most fuel-efficient method possible with exactly two impulsive burns because both burns are performed at the optimal points on the transfer ellipse — the periapsis and apoapsis — where the vis-viva equation yields the minimum total velocity change. Any other two-burn path between the same orbits requires more Δv. The maneuver was first described mathematically by Walter Hohmann in 1925 and has been used in nearly every space mission since, from early Sputnik-era satellites to the Mars Science Laboratory (Curiosity rover) and the James Webb Space Telescope.
How long does a Hohmann transfer to GEO (geostationary orbit) take?
A Hohmann transfer from Low Earth Orbit (400 km altitude) to Geostationary Orbit (35,786 km altitude) takes approximately 5.25 hours — exactly half the orbital period of the transfer ellipse. The transfer ellipse has a semi-major axis of about 24,478 km. During this time the spacecraft coasts freely with no engine firing, traveling from the periapsis (at LEO altitude) to the apoapsis (at GEO altitude). The first burn requires about 2.43 km/s and the second burn about 1.45 km/s, for a total of approximately 3.88 km/s — the baseline budget for any satellite reaching geostationary orbit from LEO.
How long does an Earth-to-Mars Hohmann transfer take?
A heliocentric Hohmann transfer from Earth's orbit (1 AU = 149.6 million km) to Mars's orbit (1.524 AU = 228 million km) takes approximately 259 days — about 8.5 months. The transfer ellipse semi-major axis is about 188.8 million km, and the spacecraft coasts the entire distance with no fuel burn. The heliocentric delta-V is about 2.95 km/s at departure and 2.65 km/s at Mars arrival (total ~5.6 km/s). Because Earth and Mars must be in a specific relative alignment at launch (Mars roughly 44° ahead of Earth), launch windows occur only every 26 months — the Earth-Mars synodic period.
What is the vis-viva equation and why is it used here?
The vis-viva equation is the fundamental relationship between an orbiting object's speed at any point and its position: v = √(μ(2/r − 1/a)), where μ is the gravitational parameter, r is the current distance from the central body's center, and a is the orbit's semi-major axis. For a circular orbit, a = r, so it simplifies to v = √(μ/r). For the transfer ellipse, a = (r₁ + r₂)/2. By applying vis-viva at both burns — departure and arrival — we get precise velocity values at each maneuver point, making it straightforward to compute the required Δv for each burn as the difference between transfer ellipse velocity and circular orbit velocity at that radius.
When should I use a bi-elliptic transfer instead of Hohmann?
A bi-elliptic transfer uses three burns and passes through a very high intermediate orbit. It is more propellant-efficient than a Hohmann transfer when the ratio of final to initial orbit radius (r₂/r₁) exceeds about 11.94. Above a ratio of 15.58, a bi-elliptic transfer is definitively more efficient regardless of the intermediate orbit altitude chosen. For typical Earth orbit transfers — such as LEO to GEO (ratio ≈ 6.2) — the Hohmann transfer is more efficient. Bi-elliptic advantages become significant for transfers like LEO to deep space or highly eccentric orbits. The calculator shows the orbit ratio and alerts you when a bi-elliptic transfer is worth considering.
How do I calculate propellant mass for a Hohmann transfer?
This calculator uses the Tsiolkovsky rocket equation: Δm = m₀ × (1 − e^(−Δv/(Isp × g₀))), where m₀ is the initial spacecraft mass in kg, Isp is the engine specific impulse in seconds, g₀ = 9.80665 m/s², and Δv is the total delta-V in m/s. Expand the 'Include propellant calculation' section, enter your spacecraft mass and Isp, and the propellant mass, dry mass, and propellant fraction are shown automatically. Typical values: chemical engines have Isp of 300–450 s; ion thrusters 1,500–10,000 s. A LEO-to-GEO transfer for a 5,000 kg spacecraft with a 450 s Isp engine requires roughly 2,000 kg of propellant — about 40% of the spacecraft mass.