How do dividends, rental income, or a pension change my required FIRE number?

Any reliable income stream reduces the amount your portfolio must cover, so subtract it from your annual expenses before applying the multiple. If you spend $60,000 and expect $20,000 a year from a pension or rental profit, your portfolio only needs to fund the remaining $40,000, implying about $1 million at a 4% rate instead of $1.5 million.

Be conservative about the reliability and inflation protection of that income. A pension without cost-of-living adjustments loses purchasing power over decades; rental income carries vacancy, repair, and management risk. For Social Security, which most FIRE planners treat as a later-life backstop, factor in when benefits actually begin. Layering guaranteed income under your essential expenses can meaningfully lower both your number and your reliance on market performance.