The CFO-grade capacity model: back into headcount from ARR target, quota, average attainment, ramp, and attrition. See your gap, hires needed, and total loaded cost.
ARR ÷ (quota × attainment). New hires get a ramp discount of (12 − ramp/2) ÷ 12, then we add an attrition backfill on top. That's the number your CFO will actually approve.