How Does Inflation Affect My Retirement Number?

Inflation is the retirement planning variable that most people understand in the abstract but underestimate in practice. They know prices go up over time. What they do not always grasp is the compounding nature of that erosion — how 3% inflation for 25 years turns $1 into $0.48 in real purchasing power, or how a retirement income that feels comfortable at 65 can feel tight by 80.

Inflation affects your retirement plan in two distinct ways that require different responses: it erodes the purchasing power of fixed income sources, and it raises the nominal amount you need to save to meet a real spending target. Both effects are significant and both are often underaccounted for.

The Purchasing Power Effect

At 3% annual inflation — close to the long-run US average — $1 today is worth approximately $0.74 in ten years, $0.55 in twenty years, and $0.41 in thirty years. For a retiree at 65 planning for a 25-year retirement to 90, the purchasing power of a fixed dollar amount at the end of that period is roughly half what it was at the start.

This matters enormously for fixed income sources. A pension paying $3,000 per month with no cost-of-living adjustment pays $3,000 per month for life — in nominal terms. But at 3% inflation, that $3,000 has the purchasing power of about $1,560 per month in today's dollars by age 85. The pension did not change. Everything else got more expensive. This is why pension holders need supplemental savings even when the pension seems generous today.

Social Security has a cost-of-living adjustment tied to CPI, which partially protects against this erosion — though the COLA does not always keep pace with the actual inflation experienced by retirees, whose spending is weighted more heavily toward healthcare than the general CPI basket. A pension or annuity without a COLA, however, loses real value year after year throughout retirement with no adjustment mechanism.

The Retirement Number Effect

Inflation also affects how much you need to save before you retire. If you plan to spend $75,000 per year in retirement and you are 30 years away from retirement, the $75,000 figure is in today's dollars. In thirty years at 3% inflation, $75,000 of today's spending requires approximately $182,000 in nominal terms — more than twice as much in dollar terms, for the same real lifestyle.

This means the retirement number you calculate today — your FIRE number, your savings target — needs to account for where you are in this inflation timeline. A 35-year-old targeting a $2,000,000 retirement portfolio in today's dollars needs roughly $4,860,000 in nominal terms at 65, assuming 3% annual inflation over 30 years. That nominal figure is not the goal — it is just what the real goal looks like when expressed in future dollars.

This is why retirement calculators that show results in real dollars — today's purchasing power — are more useful for planning purposes than those showing nominal future dollars. A $4,860,000 nominal balance in 30 years does not mean you can spend like someone with $4,860,000 today. Showing the result in today's dollars eliminates this confusion.

How Inflation Affects Different Asset Classes

Not all assets respond to inflation the same way, which matters for how you structure a retirement portfolio.

Equities — stocks — have historically kept pace with and often exceeded inflation over long periods. Companies can raise prices, which preserves real earnings and stock values over time. A diversified equity portfolio is one of the better long-run hedges against inflation, though it comes with significant short-term volatility. This is the primary reason equities are the core of most retirement portfolios despite that volatility.

Bonds — particularly fixed-rate bonds — are poor inflation hedges. A bond paying 4% annually loses real value when inflation runs above 4%. The 2022 bond drawdown was a sharp reminder of this: rising inflation eroded the real value of fixed-rate bonds simultaneously with rising rates pushing their market prices down. TIPS — Treasury Inflation-Protected Securities — adjust principal with CPI and offer explicit inflation protection, at the cost of lower nominal yields.

Real estate and rental income generally keep pace with inflation over time as rents and property values rise with the broader price level. Cash and HYSA accounts are partially protected in rising-rate environments when interest rates track inflation, but in low-rate periods cash earns a negative real return. For more on how rental income interacts with a retirement plan over time, see how rental income changes your FIRE number.

Inflation in Retirement Is Different From Inflation Before Retirement

The inflation rate that matters for retirees is not exactly the same as the headline CPI figure. Retirees spend more of their income on healthcare and housing than the average consumer, and healthcare inflation has historically run 2% to 3% above general CPI. Someone who budgets for 3% inflation on all spending is likely underestimating the healthcare component.

A retiree whose healthcare costs represent 15% of spending and grow at 5% annually while everything else grows at 3% is experiencing a blended inflation rate closer to 3.3%. Over 25 years, that 0.3% difference compounds into a meaningful reduction in real purchasing power. It is a small adjustment but worth knowing when choosing an inflation assumption in a retirement projection.

What Inflation Rate to Use in Your Projection

For most long-run retirement projections, 3% is the standard inflation assumption — close to the US historical average and the Federal Reserve's long-run target of 2% plus a small buffer for uncertainty. Using 2% is slightly optimistic. Using 4% is conservative but not unreasonable given recent inflation history.

The key is consistency: whatever inflation rate you use should be the same rate you use to discount future spending, adjust income sources, and calculate your real vs nominal return rate. Mixing assumptions — using a 10% nominal return rate but a 3% inflation rate and showing results in future dollars — produces an overoptimistic projection. See what return rate to use in your retirement calculator for how nominal and real returns interact.

At NumberToRetire.com, the inflation rate input in the Assumptions section applies consistently across the projection: it adjusts the IRS contribution limits forward (historically around 3.5% per year), adjusts your spending target in future-dollar terms, and is the basis for the real vs nominal toggle in the results panel. The default is 3%. Changing it to 2% or 4% and running the projection shows how sensitive your retirement date and balance are to the inflation assumption — which is itself a useful calibration exercise.

The Real vs Nominal Toggle

NumberToRetire.com shows results in real dollars by default — your projected balance and monthly income expressed in today's purchasing power. This means the $1,400,000 projected balance at 65 is what that money buys today, not what $1,400,000 will be worth in nominal terms in 30 years.

The nominal view is available via the toggle and shows the larger future-dollar figures. Both are correct; they describe the same underlying reality from different perspectives. Real dollars are more useful for planning because they answer the question you actually care about: will I be able to afford the lifestyle I want? Nominal dollars answer a different question: what will the account balance say on the statement?

Using real dollars also makes the retirement savings target more stable over time. If you are targeting $1,500,000 in today's dollars, that target does not change as inflation runs its course — you are always comparing like to like. A nominal target, by contrast, needs to be updated every few years to reflect accumulated inflation.