New on FinoLib · Volume V: Personal Finance
I have just published a new article on FinoLib, my free finance education library: How Much Do You Need to Retire? Social Security, Pensions, RMDs. It is part of Volume V: Personal Finance. It is part 1 of a 3-part guide. Below is a summary of the topic in plain, expert language, so you can follow the idea even before you open the full article.
The idea in plain words
A simple rule of thumb says you need about 25 times the amount your investments must pay you each year. That yearly amount is your spending minus Social Security and any pension. When you start Social Security, and in what order you draw from pre-tax accounts before the government forces withdrawals, can change a household’s lifetime income and tax bill by six figures. These are timing choices, and getting them right costs nothing if you plan early.
Key points
■Estimate spending from your own expenses; 70%–80% of gross pay is a rough check, not a plan.
■The 4% rule describes 30-year U.S. history with 50%–75% stocks; longer retirements, fees and taxes call for less.
■Social Security replaces a larger share of low earnings than high earnings, and each year of delay from 62 to 70 raises the check for life; the break-even against claiming at 62 is about age 80.
■A pension’s vesting schedule, payout option and inflation protection decide what it is worth.
A closer look
There are two ways to estimate retirement spending: from income, which is quick, or from expenses, which is better. Either estimate becomes a portfolio target by the same rule of thumb: roughly 25 times the annual amount the portfolio must supply — 1 ÷ 0.04, the inverse of the 4% withdrawal rate examined in 10.2. At a more cautious 3.5%, the multiple is 1 ÷ 0.035 ≈ 28.6.
The income-replacement heuristic says retirement spending will be about 70%–80% of pre-retirement gross income. It exists because a large slice of a paycheck is never spent on living: of $75,000 gross, $4,500 goes to the 401(k), and federal income tax ($6,108) and FICA (7.65% × $72,400 = $5,538.60, Part 1.6: Paychecks Decoded) also come off the top. Take-home pay is $2,163.60 × 26 = $56,253.60; adding back $2,600 of health premiums gives about $58,854 of living costs — 78% of gross. In retirement, saving and payroll tax disappear, while healthcare (Part 8.2, 10.9: Medicare at 65, IRMAA, and the Pre-65 Health Insurance Gap) tends to grow.
The expense-based method builds the number line by line, separating what you must pay from what you would like to pay; essentials are what a guaranteed income floor should cover (10.7).
The 4% rule, originating from financial planner William Bengen’s research in the 1990s, holds that withdrawing 4% of a portfolio’s value in the first year of retirement, then adjusting that dollar amount for inflation every year after, historically survived every rolling 30-year period in U.S. market history without running out of money.
Social Security calculates a benefit from a worker’s highest 35 years of earnings, indexed to growth in national average wages, producing a Primary Insurance Amount (PIA) — the monthly benefit payable at Full Retirement Age (FRA), which is 67 for anyone born in 1960 or later. Claiming earlier or later than FRA permanently adjusts the benefit up or down.
A worked example
Worked Example — The $75,000 Household’s Target
At 70% of the household’s $75,000 income, estimated retirement spending is $75,000 × 70% = $52,500 per year. At 25 times that figure, the target portfolio is $52,500 × 25 = $1,312,500 — the number Parts 6 and 7 are working toward. Social Security’s offset. Using the 2026 average retirement benefit of $2,071 a month purely as an illustration (the household’s own benefit depends on its earnings record, 10.3): $2,071 × 12 = $24,852 a year. The portfolio then needs to supply $52,500 − $24,852 = $27,648, and 25 × $27,648 = $691,200.
When This Breaks
The 70%–80% heuristic assumes a typical saver with a typical tax bill. It overstates the need for someone who saved 25% of pay and understates it for a low saver, for anyone still paying rent or a mortgage, and for anyone retiring before 65 who must buy health coverage until Medicare (10.9: Medicare at 65, IRMAA, and the Pre-65 Health Insurance Gap).
Why It Matters
The 4% figure is a historical observation, not a law of physics, and has drawn serious criticism: some researchers argue that higher valuations and lower expected future returns justify a more conservative starting rate somewhat below 4% for today’s retirees (see the box below); others advocate dynamic strategies — adjusting spending up in good market years and down in bad ones, rather than a fixed inflation-adjusted dollar amount regardless of how the portfolio actually performs.
What the full article covers
The full article includes worked examples, a recap, a reveal-on-click quiz and the official sources behind every figure.
Volume V: Personal Finance
Read the full article on FinoLib
The complete article, How Much Do You Need to Retire? Social Security, Pensions, RMDs, with every worked example, diagram, quiz and source, is free to read in Volume V, Personal Finance on finolib.com.
Explore the Finance Education Series: Vol. II — Capital Markets · Vol. I — Global Economy · Vol. III — Finance Encyclopedia · Vol. IV — Finance Careers · Vol. V — Personal Finance