How to Find Your Retirement Income Gap

Most retirement planning starts with a portfolio target and works backwards. The retirement income gap starts from the other end: what will you spend, what arrives regardless of markets, and what is left over for savings to cover?

That last figure is the only part your portfolio actually has to fund, and it is almost always smaller than the headline spending number. Sizing it correctly changes both how much you need and how you should invest it.

The subtraction, and why order matters

Three steps.

Estimate annual spending in retirement. Not your current income — your spending, as it will be. Some costs fall: commuting, work clothes, payroll taxes, retirement contributions themselves, and often the mortgage. Others rise, healthcare most reliably.

Add up guaranteed lifetime income. Social Security, pensions, annuities. These arrive whether markets rise or fall and continue for life. The Social Security claiming guide and the spousal benefit guide cover what to expect from the largest component.

Subtract. What remains is the gap.

The order matters because it stops you sizing a portfolio against total spending. A household spending $70,000 with $45,000 of guaranteed income does not need a portfolio funding $70,000. It needs one funding $25,000 — and at a 4% withdrawal rate that is a target of roughly $625,000 rather than $1.75m. The retirement income gap calculator does the subtraction and the multiplication together.

Separate essential spending from discretionary

The single most useful refinement is splitting the spending figure in two.

Essential — housing, food, utilities, insurance, healthcare, transport, taxes. Costs that continue whatever happens.

Discretionary — travel, gifts, hobbies, meals out, upgrades. Things you could reduce in a bad year without harm.

Now compare guaranteed income against essentials specifically. That comparison answers a more important question than the overall gap: can a market crash affect your ability to keep the lights on?

If guaranteed income covers essentials, the answer is no. Everything the portfolio funds is discretionary, so a bad year means a smaller holiday rather than a crisis. That security has a direct investment consequence — you can hold more equities than the overall numbers suggest, because you have genuine capacity to absorb volatility.

If there is an essential gap, that is the part worth closing with something certain. It is the strongest argument for delaying Social Security, and the narrow case where an annuity earns its place, as the annuity payout guide covers.

Where the estimate usually goes wrong

Healthcare before Medicare. The biggest omission for anyone retiring early. Employer coverage ends with the job and the replacement is expensive — the retirement healthcare cost calculator and the COBRA guide cover the bridge years. Note the interaction: marketplace subsidies are income-tested, so a drawdown that keeps taxable income low reduces premiums substantially.

Tax. The gap is spending, but withdrawals are taxed depending on which account they come from. A gap of $25,000 funded entirely from traditional accounts requires withdrawing meaningfully more than $25,000. The withdrawal sequencing guide covers managing that, and it is why account mix matters as much as balance.

Inflation. Most pensions do not adjust. Social Security does. A gap that looks manageable at 65 grows if the guaranteed side is partly fixed — over 24 years at 3%, prices double, as the rule of 72 shows.

Lumpy costs. A roof, a car, a wedding, a child needing help. An annual average hides expenses that arrive all at once, and they usually arrive in the worst years.

The first years cost more. Early retirement spending is frequently higher than later, because that is when people travel. Spending tends to decline through the middle years and rise again late as care costs appear.

Your retirement income gap changes shape over time

Treating it as one number for thirty years is the most common structural error, because the components start at different dates.

Someone retiring at 62 may have no guaranteed income at all for several years, a large gap the portfolio must cover alone, and then a much smaller gap once Social Security begins. Add required distributions later and the gap can close entirely — or reverse into forced income exceeding spending.

Those early years are doing something valuable that a single average conceals. They are the lowest-income years you will have, which makes them the right time for Roth conversions and for realising gains cheaply.

So map the gap by year, not as an average. The shape tells you where the risk is concentrated and where the tax opportunities sit.

What to do once you know it

Fund the near years differently from the far ones. Money needed in the first several years should not be exposed to sequence risk. A bond ladder covering early spending means you never sell equities into a decline.

Close an essential gap with certain income before optimising anything else. Delaying Social Security is usually the cheapest way to buy guaranteed inflation-adjusted income that exists.

Recheck it annually. Spending changes, health changes, and the guaranteed side changes when a benefit starts.

Consider partial work. A modest earned income during the early years does double duty: it reduces the gap directly and lets the portfolio stay invested through the period when sequence risk is highest. A few years of part-time earnings can be worth more than a large addition to the portfolio, precisely because of when it lands.

The framing is worth keeping even if the arithmetic stays rough. Total spending is a scary number. The gap is a manageable one, and it is the number that actually describes the problem.