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Specific Impulse Converter

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Convert specific impulse values between seconds, meters per second, feet per second, and kilometers per second. Specific impulse is a key metric for evaluating rocket engine efficiency.

Quick Reference

Performance category
Good Performance
LOX/RP-1, LOX/LH2, Most bipropellants
Seconds
350.0 s
Standard unit
Effective Exhaust Velocity
3,432.3 m/s
Meters per second
Feet per Second
11,260.9 ft/s
Imperial velocity
Kilometers per Second
3.432 km/s
High-speed units

Calculation context

Thrust per Mass Flow
3,432.3 N/(kg/s)
Input Value
350.000 seconds
Effective exhaust velocity3,432 m/sIsp in seconds converts directly through ve = Isp × g₀low chemical / cold gaselectric propulsion350.0 s

Isp is exhaust velocity divided by g₀

Seconds can feel abstract, so the diagram keeps the equivalent exhaust velocity visible. Higher Isp means more impulse per unit propellant flow, not necessarily more thrust.

Specific impulse
350.0 s
Exhaust velocity
3.432 km/s
Thrust per mass flow
3,432 N/(kg/s)
Category
Good Performance
Common reference points
Cold Gas Thruster150 s
Hydrazine Monopropellant230 s
LOX/RP-1350 s
LOX/LH2450 s
Hall Thruster1,500 s
Ion Engine3,000 s

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