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    Rocketry

    Payload Mass Calculator

    Maximum payload a single stage can carry for a given delta-v, propellant load and structure.

    m_payload = m_p / (e^(Δv/(Isp·g₀)) − 1) − m_dry

    Inputs

    s

    Results

    Maximum payload
    35.1219 tonnes
    Required mass ratio
    3.319
    Stage Δv with zero payload
    8.67805 km/s
    Payload fraction of lift-off mass
    24.54 %
    Worked solution
    1. Mass ratio R = e^(Δv/(Isp·g₀)) = 3.31901
    2. (m_d + m_p + m_pl)/(m_d + m_pl) = R ⇒ m_pl = m_p/(R − 1) − m_d
    3. m_pl = 100,000 / 2.31901 − 8,000 = 35,122 kg

    How the result changes

    Payload (tonnes) plotted against Delta-v (km/s), from one quarter to four times your input, with your input marked.01002002468Delta-v (km/s)Payload (tonnes)your input
    Payload vs delta-v

    How it works

    Payload is what is left after structure and propellant. Real launch vehicles deliver only about 2–4% of their lift-off mass to low Earth orbit.

    Variables

    • m_p — propellant mass
    • m_dry — structural (empty stage) mass

    Assumptions and limits

    • Single stage
    • Ideal rocket equation
    • Structural mass fixed regardless of payload

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