Hohmann Transfer Calculator
Enter the central mass and two circular orbit radii to find the two-burn Hohmann transfer: the delta-v of each burn, the total, and the coast time.
How to use the Hohmann transfer calculator
- Enter the central body's mass in kilograms or solar masses.
- Enter the starting and target circular orbit radii in metres.
- Read each burn's delta-v, the total, and the transfer coast time.
Examples
LEO to GEO around Earth
mass = 5.972e24 kg, r1 = 6.671e6 m, r2 = 4.2164e7 m
total delta-v about 3.90 km/s, transfer about 5.27 hours
First burn of that transfer
same orbits, departure burn
delta-v1 about 2428 m/s
Frequently asked questions
What is a Hohmann transfer?
It is the most fuel-efficient two-burn manoeuvre between two coplanar circular orbits. One burn raises the orbit into an ellipse, a second circularises it.
How is Hohmann transfer delta-v calculated?
With mu = G x M and a = (r1 + r2) / 2, each burn is the difference between the circular speed and the transfer ellipse speed at that radius.
What is the transfer time?
It is half the period of the transfer ellipse, t = pi x sqrt(a^3 / mu), the coast time from the first burn to the second.
Why does a LEO to GEO transfer need about 3.9 km/s?
Departing low Earth orbit costs roughly 2.43 km/s and circularising at geostationary altitude adds about 1.47 km/s, totalling near 3.9 km/s.
Does the order of the two orbits matter?
No for the total. Swapping the radii swaps which burn is larger, but the sum of the two delta-v values and the transfer time stay the same.
Related tools
Orbital Velocity Calculator
Calculate circular orbital velocity and period from the central mass and orbit radius, using v = sqrt(GM/r). Enter kilograms or solar masses.
Orbital Period Calculator
Calculate orbital period from Kepler's third law, T = 2 pi sqrt(a cubed / GM). Enter the semi-major axis and central mass to get seconds, days and years.
Escape Velocity Calculator
Calculate escape velocity from any planet, moon or star with v = sqrt(2GM/r). Pick Earth, Mars or Jupiter presets or enter mass and radius. Free tool.
555 Timer Calculator
Calculate 555 timer astable frequency, period, high and low times and duty cycle from R1, R2 and the timing capacitor. Free oscillator design helper.
Absolute Humidity Calculator
Calculate absolute humidity in grams of water vapor per cubic meter from air temperature and relative humidity. Fast, free and works in your browser.
Allele Frequency Calculator
Find allele frequencies from genotype counts. Enter the number of AA, Aa and aa individuals to get the A and a allele frequencies and allele totals.