Net worth
Withdrawal rate
Also known as: 4% rule.
Withdrawal rate is the percentage of net worth withdrawn in the first year of retirement, later adjusted for inflation; the classic reference is 4%.
It comes from studies of the US market over 30-year horizons; for globally diversified portfolios and early retirement, many planners outside the US use 3% to 3.5%.
The biggest risk is sequence of returns: a sharp drop in the first years of retirement damages the capital far more than the same drop late in retirement.