Retirement Calculator
How large a corpus you need, and whether your saving rate gets you there.
Last updated
Your details
Result
- Corpus needed at retirement
- $61,424,169.83
- Monthly expenses at retirement
- $229,739.65
- You must invest monthly
- $17,401.04
- Your existing savings will grow to
- $0.00
- Years to build it
- 30 years
To fund 25 years of inflation-adjusted spending
$40,000.00 today, inflated over 30 years
The two-stage calculation
Retirement planning is two problems stacked. First: how much will you spend, in the money of the year you retire? Today's expenses inflated over the years remaining. At 6% inflation, spending doubles roughly every twelve years, so a thirty-year horizon multiplies it by close to six.
Second: how large a pot funds that spending for the rest of your life? This is an annuity calculation using the real return — your post-retirement return minus inflation — so the withdrawals keep their purchasing power rather than shrinking every year.
Why the real return is the number that matters
A 7% return with 6% inflation is not a 7% return. In purchasing-power terms it is about 0.94%. Plans that use nominal returns against inflated expenses overstate how long a corpus lasts, often by decades.
This is also why the gap between pre- and post-retirement return assumptions matters. Most people shift toward safer, lower-yielding assets at retirement, which is prudent but reduces the real return exactly when withdrawals begin.
Formula & methodology
What this calculator assumes
- Uses the real return — nominal return minus inflation — so withdrawals keep their purchasing power rather than shrinking each year.
- Excludes pensions, social security and any other guaranteed income; subtract these from expenses before entering them.
- Assumes constant returns and inflation, which no real economy delivers.
Sources
- Brealey, Myers & Allen, Principles of Corporate Finance, 13th edition, McGraw-Hill, 2019 — compounding and annuities.
Frequently asked questions
Why is the required corpus so large?
Because it must survive decades of inflation while being drawn down. The number looks alarming in future money, but so will salaries and asset prices by then.
Does it include a pension or social security?
No. If you expect guaranteed income in retirement, subtract its monthly value from your expenses before entering them.