Klyrify guide
How Other Retirement Income Can Change a FIRE Number
A basic FIRE calculation assumes the portfolio funds all expenses. A pension, public retirement benefit, or dependable net rental income can reduce the amount the portfolio must cover, but timing, taxes, inflation, and reliability matter.
The Adjusted FIRE Number Formula
Standard formula (no outside income): FIRE Number = Annual Expenses x 25
With expected outside income: Adjusted FIRE Number = (Annual Expenses - Expected Annual Income) x 25
Illustrative example: - Annual expenses: $70,000 - Social Security expected: $18,000/year - Pension: $12,000/year - Expected income total: $30,000 - Net expenses needing portfolio coverage: $40,000 - Adjusted FIRE Number: $40,000 x 25 = $1,000,000
Without accounting for SS and pension: $70,000 x 25 = $1,750,000. The difference is $750,000 less needed — representing 5-10 fewer years of work for many people, as an estimate based on the assumptions above.
Important: this simplified formula assumes the guaranteed income is already being received for the entire retirement period. Social Security cannot be claimed before age 62, and many pensions have their own start age — so if you plan to retire earlier than that, you still need a separate portfolio (or bridge account) large enough to cover 100% of expenses until that income actually begins. See "Social Security for Early Retirees" and the FAQ below for how to model the gap years.
How Different Income Assumptions Change the FIRE Number
At $60,000/year expenses (standard FIRE number: $1,500,000):
| Annual Income Source | Amount | FIRE Number Reduction | New Target |
|---|---|---|---|
| No outside income | $0 | — | $1,500,000 |
| Part-time work | $15,000 | -$375,000 | $1,125,000 |
| Social Security (modest) | $18,000 | -$450,000 | $1,050,000 |
| Pension (moderate) | $20,000 | -$500,000 | $1,000,000 |
| SS + pension combined | $35,000 | -$875,000 | $625,000 |
| Rental income (net) | $24,000 | -$600,000 | $900,000 |
United States Example: Social Security for Early Retirees
Social Security rules and benefit ages are specific to the United States and can change. Verify current details with the Social Security Administration before relying on an estimate.
Reduced benefits from fewer working years. Social Security is calculated using your 35 highest-earning years. Retiring at 45 instead of 65 means 20 years of zero wages in the calculation, significantly reducing benefits.
Delayed claiming increases benefits. Each year of delay beyond full retirement age (66-67, depending on birth year) increases monthly benefits by approximately 8%, up to age 70. Claiming at 62 instead of full retirement age reduces the monthly payment; waiting from 62 to 70 roughly doubles it.
Strategy: Many early retirees prefer to build their portfolio to fund 100% of expenses independently, then treat eventual SS as a bonus that shortens the portfolio's later-years drawdown — rather than baking it into the number from day one, as the worked example above does. If you do include guaranteed income in your Adjusted FIRE Number, make sure your bridge-year plan (above) actually covers the years before that income starts.
Pension Lump-Sum Equivalent Value
To compare a pension to portfolio assets, calculate the equivalent lump sum:
Pension Equivalent = Annual Pension / Withdrawal Rate
| Annual Pension | Equivalent Portfolio (4%) |
|---|---|
| $10,000/year | $250,000 |
| $20,000/year | $500,000 |
| $30,000/year | $750,000 |
| $40,000/year | $1,000,000 |
At a constant 4% withdrawal assumption, $30,000 of annual pension income offsets the same first-year spending amount as $750,000 of portfolio value. The risks and inflation features are not equivalent.
Rental Income and FIRE
Rental income reduces your FIRE number dollar-for-dollar times 25. Use net rental income (after mortgage, taxes, insurance, maintenance, and vacancy), not gross rent. A property generating $2,500/month gross might produce $1,200-1,500/month net — always use the net figure.
Frequently Asked Questions
Should I count pension income before or after taxes? After taxes. Calculate your expected net pension income after federal and state income taxes, then use that figure to reduce annual expenses. Pre-tax income overstates the actual spending reduction.
What if my pension has a cost of living adjustment? A pension with a COLA is more valuable than a fixed pension — it maintains real purchasing power over time. This is a significant advantage that effectively hedges inflation for that portion of retirement income.
Can I retire early with a pension that starts at 60? Yes — but you need to fund the gap years from your portfolio. Model two phases: pre-pension (full portfolio coverage) and post-pension (portfolio covers only expenses minus pension). The FIRE number calculator can help you model the pre-pension phase.