Physics

Specific Impulse Calculator

Find a rocket engine's specific impulse from thrust and propellant flow.

Calculated Output

Specific impulse 309.99

Exhaust velocity 3,040

Formula: Isp = thrust ÷ (ṁ·g₀)

Step-by-Step Breakdown

1. Values used:

2. Thrust = 7,600,000 N

3. Propellant flow = 2,500 kg/s

5. Specific impulse = 309.99

6. Exhaust velocity = Thrust / Propellant flow = 7,600,000 / 2,500 = 3,040

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The math behind it

Isp = thrust ÷ (ṁ·g₀). Higher Isp means more thrust per unit of propellant burned.

7.6 MN thrust, 2500 kg/s → about 310 s.

Typical values?

Solid boosters ~250 s, kerosene ~300 s, hydrogen ~450 s, ion drives thousands.