Rocket Delta-V Calculator

Reviewed by the CalculatorHub team, edited by James Graham. Tsiolkovsky rocket equation with standard gravity g0 = 9.80665 m/s squared (NIST). Last verified 15 June 2026.

The Tsiolkovsky rocket equation is the fundamental law of rocketry: it quantifies how much velocity change (delta-v) a rocket can achieve for a given engine efficiency and propellant fraction. The equation is dv = Isp times g0 times the natural log of m0/mf, where Isp is specific impulse in seconds, g0 is standard gravity, m0 is initial (fully loaded) mass, and mf is final (dry) mass. Enter your rocket's specific impulse, wet mass, and dry mass to compute the available delta-v and mass ratio.

Specific impulse, Isp (seconds) Merlin vacuum ~348 s; Raptor ~363 s; RL-10 ~465 s

Wet (initial) mass, m0 (kg) Total launch mass including propellant

Dry (final) mass, mf (kg) Structure plus payload after all propellant burned

Delta-v (m/s)

4,903.53

Delta-v (km/s)

4.90

Mass ratio (m0/mf)

5.00

Tsiolkovsky rocket equation

dv = Isp * g0 * ln(m0 / mf)
g0 = 9.80665 m/s^2 (standard gravity, NIST)

Delta-v is in m/s when Isp is in seconds. The propellant mass fraction is (m0 - mf) / m0. A mass ratio of 5 gives ln(5) = 1.609, so with Isp = 311 s, delta-v = 311 * 9.80665 * 1.609 = 4,904 m/s, sufficient for a single stage to reach low Earth orbit in an ideal (no drag, gravity loss) scenario.

Mission delta-v requirements

Low Earth orbit (LEO): about 9,400 m/s total from Earth surface. Geostationary transfer: about 2,500 m/s from LEO. Trans-lunar injection: about 3,100 m/s from LEO. Mars transfer orbit: about 3,600 m/s from LEO. Jupiter: about 9,000 m/s from LEO. These figures include typical gravity and atmospheric drag losses.

Rocket delta-v: frequently asked questions

What is delta-v in rocketry?

Delta-v (change in velocity, written dv) is the total velocity change a spacecraft can achieve by expelling propellant. It is the fundamental measure of a rocket's capability. Reaching low Earth orbit requires about 9,400 m/s of delta-v; a Mars transfer needs about 3,600 m/s more.

What is the Tsiolkovsky rocket equation?

The Tsiolkovsky equation is dv = Isp * g0 * ln(m0/mf), where Isp is specific impulse (seconds), g0 = 9.80665 m/s squared (standard gravity), m0 is initial (wet) mass, and mf is final (dry) mass after propellant is expended. ln is the natural logarithm.

What is specific impulse (Isp)?

Specific impulse is a measure of engine efficiency: the thrust produced per unit weight of propellant consumed per second, measured in seconds. Kerosene/LOX engines (like Falcon 9's Merlin) have Isp around 282 s at sea level. Hydrogen/LOX engines reach 450 s in vacuum. Ion engines exceed 3,000 s.

What is the mass ratio, and why does it matter?

The mass ratio is m0/mf (wet mass divided by dry mass). Delta-v scales as the natural log of the mass ratio. Doubling the mass ratio does not double the delta-v because of the logarithm. This is why multi-stage rockets are used: each stage discards empty tankage and structure.

What delta-v is needed for common missions?

Low Earth orbit: about 9,400 m/s. Geostationary orbit: about 11,600 m/s from surface. Lunar orbit: about 13,000 m/s from surface. Mars orbit: about 13,000-14,000 m/s from surface. Earth escape velocity: about 11,200 m/s.

Official sources

NASA Glenn Research Center: Rocket propulsion basics: grc.nasa.gov.
NIST standard gravity g0 = 9.80665 m/s squared: physics.nist.gov.

Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.