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    Rocketry

    Rocket Fuel (Propellant Mass) Calculator

    Propellant needed to deliver a target delta-v, plus mass flow and burn time.

    m_p = m_f · (e^(Δv / (Isp·g₀)) − 1) · ṁ = F / (Isp·g₀)

    Inputs

    s

    Results

    Propellant mass
    12,326.2 kg
    Initial (wet) mass
    17,326.2 kg
    Mass flow rate
    31.866 kg/s
    Burn time
    386.81 s
    6 min 26.8 s
    Worked solution
    1. Δv/(Isp·g₀) = 1.24278
    2. m_p = 5,000 × (e^1.24278 − 1) = 12,326 kg
    3. ṁ = 100,000 / (320 × 9.80665) = 31.866 kg/s

    How the result changes

    Propellant (kg) plotted against Delta-v (km/s), from one quarter to four times your input, with your input marked.0200,000400,000600,00051015Delta-v (km/s)Propellant (kg)your input
    Propellant vs delta-v

    How it works

    The required propellant grows exponentially with Δv. Raising Isp — for example by switching from kerosene to hydrogen — is the most powerful way to cut propellant mass.

    Variables

    • m_p — propellant mass
    • m_f — final (dry + payload) mass
    • ṁ — mass flow rate

    Assumptions and limits

    • Ideal rocket equation (no gravity or drag losses)
    • Constant thrust and Isp during the burn
    • Tank mass does not grow with propellant load

    For education only. These models are simplified and are not suitable for spacecraft navigation or safety-critical engineering. See our scientific accuracy policy.