Should I enter altitude or orbital radius?

Altitude is height above the selected body's mean radius. Orbital radius is measured from the body's center. The calculator converts altitude to radius by adding the selected body radius.

What does this calculator assume?

It assumes circular starting and target orbits, impulsive burns, and a two-body central gravity field. Plane change can be included as a single combined burn at the selected node.

How is plane change handled?

If a plane change angle is provided, it is vector-combined with the burn at the selected node: departure, arrival, periapsis, apoapsis, or automatic high-altitude node.

When is a bi-elliptic transfer better?

For very large radius ratios (r2/r1 ≳ 12), a bi-elliptic transfer can use less Δv than Hohmann. This tool focuses on classic Hohmann for simplicity.

Why do Earth-to-Mars transfers need launch windows?

A heliocentric Hohmann transfer arrives at the other orbit after a fixed coast time, so the planets must have the correct phase angle at departure.

Yes. All calculations run entirely in your browser.

Hohmann Transfer Calculator — Orbit Transfer Δv & Time of Flight

Calculate the two burns, total delta-v, transfer time, transfer ellipse, and optional propellant mass for a Hohmann transfer between circular orbits. Use it as an orbit transfer calculator for Hohmann delta-v estimates such as LEO to GEO, Earth to Mars, lunar orbit changes, and custom central bodies. Private by design: everything runs locally in your browser.

Inputs

Central body

Orbit units

Optional preset

Start orbit (h₁)

Target orbit (h₂)

Plane change at node (°) (optional)

Apply plane change with

Custom μ (km³/s²)

Custom mean radius (km)

Assumptions: circular, coplanar orbits (unless plane change specified); impulsive burns; central body point mass.

Results

Δv₁ (inject to transfer ):

–

Δv₂ (target burn ):

–

Total Δv:

–

Time of flight (half-ellipse):

–

Key speeds:

v₁ (circ), v (transfer @ r₁), v (transfer @ r₂), v₂ (circ).

Semi-major axis	–
Periapsis radius	–
Apoapsis radius	–

Propellant needed from total delta-v

Specific impulse, Isp (s)

Mass mode

Spacecraft mass (kg)

Standard gravity, g₀ (m/s²)

Enter valid mass and Isp to estimate propellant.

Diagram updates after valid inputs.

What This Hohmann Transfer Calculator Does

This tool computes the classic two-impulse Hohmann transfer between circular orbits around a selected central body. Use preset constants for the Sun, Earth, Moon, Mars, Venus, or Jupiter, or enter a custom gravitational parameter and mean radius. Enter either altitudes above the mean radius or raw orbital radii (r₁ → r₂). The calculator returns Δv₁, Δv₂, total Δv, transfer time, transfer ellipse geometry, an orbit diagram, and optional rocket-equation propellant mass. Everything runs 100% client-side for privacy and speed.

Under the hood, for radii r₁ and r₂ and gravitational parameter μ, the transfer ellipse has semi-major axis a = (r₁ + r₂)/2. Burn 1 sets the periapsis/apoapsis speed to enter the ellipse: v_t,1 = √( μ(2/r₁ − 1/a) ). Burn 2 circularizes at r₂ with v_t,2 = √( μ(2/r₂ − 1/a) ). The circular speeds are v_c,1 = √( μ/r₁ ) and v_c,2 = √( μ/r₂ ). We report Δv₁ = |v_t,1 − v_c,1| and Δv₂ = |v_c,2 − v_t,2|. The transfer time is T = π√( a³/μ ).

Plane Changes (Optional)

Need an inclination tweak? Add a plane-change angle and choose whether to combine it with the departure burn, arrival burn, periapsis burn, apoapsis burn, or the automatic high-altitude node. The combined impulse is calculated with the vector equation Δv = √(v_a² + v_b² − 2v_av_bcos Δi). Plane changes are usually cheaper where orbital speed is lower, which is why the automatic setting prefers the high-altitude node.

When to Use a Hohmann Transfer

A Hohmann transfer is the most energy-efficient two-burn strategy between circular, coplanar orbits. It’s perfect for quick sizing of maneuvers like LEO → GEO, LEO → higher LEO, lunar orbit changes, Mars satellite altitude adjustments, and heliocentric first-pass estimates such as Earth to Mars. Because the transfer is tangent to both orbits, only two burns are required: one to enter the ellipse and one to circularize, which keeps Δv low and estimates easy to compare.

Limits and Notes

Real spacecraft experience finite burn durations, gravity and drag losses during thrusting, and perturbations (e.g., J2, third-body effects). These operational details, plus phasing, lighting, and ground-station coverage, are not modeled here. For very large radius ratios (roughly when r₂/r₁ ≳ 12), a bi-elliptic transfer can beat a Hohmann in total Δv. This calculator focuses on the classic Hohmann because it captures the essential energetics with closed-form equations and gives a reliable baseline for early mission design, education, and trade studies.

Educational use only — not for mission-critical planning. Always validate with high-fidelity trajectory tools.

Worked Hohmann Transfer Examples

Load a scenario into the calculator or compare the reference results below. Values use the same equations and body constants as the live tool.

Scenario	Mode	Δv₁	Δv₂	Total Δv	Transfer time
Examples load after the calculator initializes.

Common Hohmann Transfer Benchmarks

LEO to GEO

A 200 km low Earth orbit to GEO transfer is about 3.9 km/s total before launch-vehicle losses and phasing. The coast across the transfer ellipse is about 5.3 hours.

Burn split

For LEO to GEO, most of the delta-v is the first burn at low altitude. The second burn is smaller unless a large inclination change is added.

Plane-change cost

Plane changes scale with speed. Combining an inclination change near apoapsis or another high-altitude node can be much cheaper than rotating the plane in low orbit.

Bi-elliptic threshold

When the outer-to-inner radius ratio is greater than about 11.94, a bi-elliptic transfer can require less delta-v than a Hohmann transfer, depending on the intermediate apoapsis.

Hohmann Transfers: Why They Matter

In orbital mechanics, every meter per second counts. The Hohmann transfer leverages orbital geometry to minimize Δv between circular orbits: the transfer ellipse has its periapsis at the inner orbit and apoapsis at the outer, ensuring each burn happens where it is most effective. That’s why Δv budgets for Earth observation satellites, GEO comsats, lunar orbiters, and Mars probes often start with a Hohmann estimate before moving to higher-fidelity analysis.

Use this Hohmann transfer calculator to explore trade-offs in delta-v and time of flight, test “what-ifs” (e.g., adding a small plane change), and compare bodies (Earth, Moon, Mars, Venus, Jupiter, the Sun, or custom bodies) with the correct gravitational parameters. Because calculations are client-side, it’s fast, private, and ideal for classrooms, proposals, and quick-look mission studies.

Hohmann Transfer FAQ

What is the difference between altitude and orbital radius?

Altitude is measured above the selected body's mean surface radius. Orbital radius is measured from the center of the body. For Earth, a 200 km altitude orbit has an orbital radius of about 6,571 km.

Why does radius include the body radius?

The vis-viva equation uses distance from the central mass, not height above the surface. That is why altitude mode adds the body radius before calculating speeds and transfer time.

Why does Hohmann assume circular coplanar orbits?

The closed-form Hohmann solution is the two-impulse tangent transfer between circular orbits in the same plane. Eccentric, inclined, or perturbed cases need a fuller trajectory model.

Does lowering an orbit cost the same delta-v as raising it?

The same two radii produce the same total ideal Hohmann delta-v, but the burn order changes. The first burn slows the spacecraft to enter a lower transfer ellipse, and the second burn circularizes at the lower orbit.

When can a bi-elliptic transfer beat Hohmann?

For radius ratios above about 11.94, a bi-elliptic transfer can be more efficient. The advantage depends on the chosen intermediate apoapsis and the exact radii.

Why does Earth-to-Mars need a launch window?

The heliocentric transfer time is fixed by the Sun's gravity and the transfer ellipse. Mars must be near the right phase angle when the spacecraft departs Earth orbit so both arrive at the same place at the same time.

Why are plane changes cheaper at high altitude?

Plane-change delta-v depends on velocity. Higher orbits usually have lower orbital speed, so rotating the velocity vector there costs less than doing the same angle in low orbit.

Why do real missions differ from this ideal result?

Real missions include finite burn durations, launch energy, gravity losses, drag, third-body perturbations, navigation margins, staging, targeting, and mission constraints. Treat this as a baseline, not a flight design.

Methodology and References

Equations used

The calculator uses the vis-viva equation, circular speed v = √(μ/r), transfer semi-major axis a = (r₁ + r₂)/2, half-period π√(a³/μ), vector-combined plane change, and the Tsiolkovsky rocket equation m₀/mf = e^(Δv/(Isp g₀)).

Constants

Sun	μ 132,712,440,018 km³/s²; R 695,700 km
Earth	μ 398,600.4418 km³/s²; R 6,371.0 km
Moon	μ 4,902.800066 km³/s²; R 1,737.4 km
Mars	μ 42,828.375214 km³/s²; R 3,389.5 km
Venus	μ 324,858.592 km³/s²; R 6,051.8 km
Jupiter	μ 126,686,534 km³/s²; R 69,911 km

Review status

Last reviewed: June 29, 2026. Reviewed by Starlight Robotics for educational consistency with standard two-body orbital mechanics references including NASA planetary fact sheets and common astrodynamics texts.

Use limits

Educational use only. This calculator is not a substitute for validated mission-design software, launch provider analysis, or high-fidelity numerical propagation.