Rocket fuel fraction ($f=m_{\mathrm{fuel}}/m_0$)

In an ideal rocket equation calculation where all expelled rocket propellant is called fuel, the rocket fuel fraction is its initial mass divided by the total initial mass, including payload and structure. Complete consumption leaves rocket dry mass $m_f=(1-f)m_0$ and rocket mass ratio $m_0/m_f=1/(1-f)$. The payload is one component of $m_f$, not an additional mass to add to an already inclusive $m_0$.