What does this calculator assume?

Coplanar circular orbits and impulsive burns (instantaneous). It uses the standard Hohmann transfer ellipse between radii r1 and r2. Real missions include gravity losses, finite burn durations, and perturbations.

How is plane change handled?

If a plane change angle is provided, it is vector-combined with the circularization burn at apogee (for r2>r1) or at perigee (for r2<r1). This gives the correct single-impulse combined Δv at that 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.

Yes. All calculations run entirely in your browser.

Hohmann Transfer Calculator — Δv₁, Δv₂ & Time of Flight

Enter two circular orbits to get Δv, TOF, and optional plane change. Private by design—everything runs locally in your browser.

Inputs

Central body

Orbit units

Start orbit (h₁)

Target orbit (h₂)

Plane change at node (°) (optional)

Apply plane change with

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

Results

Δv₁ (inject to transfer):

–

Δv₂ (circularize ):

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Total Δv:

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Time of flight (half-ellipse):

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Key speeds:

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

What This Hohmann Transfer Calculator Does

This tool computes the classic two-impulse Hohmann transfer between circular, coplanar orbits around Earth, the Moon, or Mars. Enter either altitudes above the mean radius or raw orbital radii (r₁ → r₂). The calculator returns Δv₁ (to inject onto the transfer ellipse), Δv₂ (to circularize at the target), total Δv, and the time of flight for the half-ellipse. 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/apogee 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 the calculator will vector-combine it with the circularization burn at the destination node, which is typically the cheapest point to rotate the plane (apogee for outward transfers, periapsis for inward). The combined impulse is Δv_combined = √( v_t,2² + v_c,2² − 2 v_t,2 v_c,2 cos Δi ). For small angles, a handy approximation is ≈ 2v sin(Δi/2).

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, and Mars satellite altitude adjustments. 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.

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 apogee 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) with the correct gravitational parameters. Because calculations are client-side, it’s fast, private, and ideal for classrooms, proposals, and quick-look mission studies.