Retirement Expense Inflation Planner
See how much your current expenses will cost after decades of inflation and the corpus you need to cover them throughout retirement.
Written by Rahman · Last reviewed
Quick answer
Someone aged 30 spending $3,000 a month today, retiring at 60 and planning through to 85, with 5% inflation and a 7% return in retirement, needs a corpus of about $2.9 million, because that $3,000 a month becomes roughly $12,966 a month by the time they retire. This works backwards from spending rather than forwards from savings, and what matters is the gap between your return and inflation rather than either number alone: 7% against 3% needs far less capital than 5% against 4%.
Results are estimates for general guidance and are not financial, tax or legal advice. Except where a calculator names a currency, figures carry no currency of their own: put in pounds and you get pounds back, put in rupees and you get rupees. Figures depend on the assumptions you enter and on rates that change over time. Check current rates and speak to a qualified adviser before acting on them.
About the Retirement Expense Inflation Planner
Most people plan retirement around how much they can save. The harder, more important question is the one this calculator answers: how much will you actually need, and is your current plan on track to get you there?
Enter your current expenses, your age and horizon, the inflation and return rates you expect, and what you have saved plus what you are contributing each month. The planner computes both the corpus you need at retirement (after inflation has had decades to push your expenses up) and the corpus you are on course to actually have. It then tells you the gap and the extra monthly contribution required to close it, turning the question "how much do I need?" into the actionable "how much more should I save?".
Corpus = C × [1 − ((1 + i) / (1 + r))^n] / (r − i)
C is the first-year retirement expense (today's expense × (1 + inflation)^years to retirement), i is the inflation rate during retirement, r is the post-retirement return on the corpus, and n is the number of years in retirement. If r equals i, the simpler formula Corpus = C × n / (1 + r) is used.
Asha is 30, spending $3,000/month today. She plans to retire at 60 and live until 85, with 5% inflation and a 7% post-retirement return. The planner says she needs a corpus of about $2.9 million at retirement to fund her inflation-rising expenses for 25 years. She already has $50,000 saved and contributes $500/month at a 10% pre-retirement return, which that projects to about $2.1 million on retirement day. The gap is roughly $803,000, a real shortfall. The actionable number: she needs to save an extra $355 every month, starting now, to close the gap entirely.
Inflation does not apply evenly across a retirement budget
Applying one inflation rate to total spending is a necessary simplification and a systematic understatement, because the categories that grow fastest are the ones that grow as a share of the budget with age.
Healthcare is the clearest case. General prices compounding at 3% multiply by 2.09 over 25 years; healthcare compounding at 5% multiplies by 3.39 over the same period. A $10,000 annual healthcare cost becomes about $33,900 rather than the $20,900 a general rate would predict, and that category is a larger share of spending at 85 than at 65.
- Long-term care sits outside most projections entirely and is among the largest single risks to a retirement plan.
- Housing costs behave differently again: a repaid mortgage removes a large fixed cost, while property tax, insurance and maintenance continue to inflate.
- Modelling healthcare separately at a higher rate is more realistic than raising the single blended rate, which overstates every other category.
Real retirement spending is not flat
Projections assume constant inflation-adjusted spending for the whole of retirement. Studies of actual spending patterns consistently find something different: higher spending in the early active years, a decline through the middle, and a rise late on as healthcare and care costs increase, often described as the retirement smile.
Assuming flat spending is therefore not neutral. It overstates the middle years and understates the end, which is the period that most threatens a plan because it coincides with a depleted portfolio and the least capacity to earn.
- Purchasing power is what the projection is really tracking. At 3%, a dollar is worth about 48 cents after 25 years.
- Some income sources inflate and some do not. Index-linked pensions and Social Security adjust; most fixed annuities do not.
- Test the plan at a higher inflation rate as well as your central estimate. The gap between 2.5% and 4% over 30 years is far larger than it looks over one.
How inflation and post-retirement return reshape the corpus
| Inflation | Post-retire return | Real return | Corpus needed |
|---|---|---|---|
| 3% | 7% | 3.9% | $1.3M |
| 5% | 7% | 1.9% | $2.9M |
| 5% | 5% | 0.0% | $3.7M |
| 7% | 7% | 0.0% | $6.4M |
| 7% | 5% | −1.9% | $8.3M |
Same person, same lifestyle, same horizon. Only the inflation and post-retirement return assumptions change. Notice how a 2-point inflation increase can nearly triple the corpus needed.
Frequently Asked Questions
Why is this different from the Retirement Calculator?
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The Retirement Calculator projects what corpus you can build from contributions. This planner tells you what corpus you actually need to maintain your lifestyle through retirement. They are two halves of the same plan and should match. If the planner says you need $3M and the calculator projects $1.5M, you have a savings gap to close.
What inflation rate should I use?
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A long-term average between 3–6% per year is reasonable in most developed economies, with developing markets often higher. Use a conservative figure. Under-estimating inflation is the most common planning mistake.
What is "real return" and why does it matter?
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Real return is your investment return after subtracting inflation. If your corpus earns 7% and inflation is 5%, the real return is just under 2%. A positive real return means your corpus stretches further; a negative real return means inflation is eroding it faster than you earn.
Why does a small change in inflation create a huge change in corpus needed?
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Inflation compounds: every year it raises the bar. Over 30 years to retirement plus 25 years in retirement, even a 2-point swing in the rate transforms the lifetime expense, which in turn changes the corpus by millions.
Is the "25× annual expenses" retirement rule safe?
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The 25× rule assumes a 4% sustainable withdrawal in real terms and roughly accounts for inflation. It can work, but it is fragile to higher-than-expected inflation, weaker investment returns or longer life expectancy. Use this planner alongside the rule to sanity-check the assumption.
Should I plan for the same inflation rate during retirement as before?
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For simplicity this calculator uses one rate throughout. In practice retirees often face medical-cost inflation that runs higher than general inflation. Try running the calculator with a slightly higher inflation rate to see how that buffer changes the corpus.
My result shows a shortfall. What should I do?
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You have three levers, in order of leverage: increase your monthly contribution (the calculator tells you exactly by how much), extend your working life by a few years (which shrinks both the gap and the years you need to fund), or accept a lower retirement expense (which lowers the corpus needed). Combining all three usually gets stubborn gaps closed.
My result shows a surplus. Am I done?
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A surplus is good news but does not mean you should ease off. Markets can underperform expectations, inflation can run higher than assumed, and life expectancy is rising. A 10–20% buffer above the projected need is a sensible cushion.
Sources
- Morningstar — The Good News on Safe Withdrawal Rates — Relevant to the "is 25× annual expenses safe?" question this page answers. 25× is the reciprocal of a 4% withdrawal rate, and Morningstar's annually re-derived estimate of that rate has moved between 3.3% and 4.0% with prevailing yields, so the multiple implied by it moves too, between roughly 25× and 30×.