The Kestrel Bay Retirement Advisors calculator shows how long your money will last in retirement, given your savings, a first-year withdrawal, an expected return and inflation. It also shows your withdrawal rate and the last year's withdrawal.
Type in four numbers and read the result as an illustration, not a forecast. Below the calculator we explain what the result means if a lot of your wealth sits in company stock.
How does the calculator work out how long your money lasts?
Each year the balance earns your expected return, then the withdrawal comes out. Next year's withdrawal is this year's raised by your inflation rate. The calculator repeats that until the balance hits zero and counts the years.
Take a hypothetical engineer with $800,000 in a rollover IRA, assuming 4.5% a year for illustration and 2.5% inflation. Taking $40,000 in year one is 5% of the balance, and the money runs out after 27 years. Pull $32,000 and it stretches to 36. Pull $48,000 and it's 21. You can reproduce every row in the calculator above.
A small change in the first withdrawal moves the answer by years. Going from $32,000 to $40,000 costs nine of them.
| Income in year one | Percent of balance | Runs out after |
|---|---|---|
| $32,000 | 4% | 36 years |
| $40,000 | 5% | 27 years |
| $48,000 | 6% | 21 years |
How should you read the result if you hold RSUs and company stock?
Start with the withdrawal rate. At about 4% of savings the money lasts three decades on these assumptions, while at 6% it's closer to two. A result under 25 years deserves a second look.
Then check what you typed as savings. It should be what you'd hold after selling company stock and paying the tax, not today's quote. RSUs are taxed as income when they vest, ESPP and option gains are taxed when you sell or exercise, and a single stock can drop by a big chunk while you wait for a better price. If that $800,000 includes $300,000 of one employer's shares, the true range of outcomes is wider than any single result shows.
Our rule of thumb: if more than a fifth of your net worth is in one stock, run the calculator twice, once with the full balance and once with that stock cut in half. If the second result changes your plan, diversification comes first. Selling has a tax cost, so we estimate it before anything is sold.
What the calculator leaves out, and how Kestrel Bay Retirement Advisors fills the gaps
The calculator is deliberately simple. It leaves out five things that change the answer:
Kestrel Bay Retirement Advisors starts with taxes. Before we suggest selling a share of company stock, we estimate what the sale costs this year and over your lifetime. The 2026 standard deduction for a single filer is $16,100, which covers only a slice of a $40,000 withdrawal.
We can't remove sequence risk, only plan around it. We'd rather keep about two years of spending in cash, because selling in a down year is what really hurts. Investing involves risk, including loss of principal.
- Taxes: withdrawals from a pre-tax 401(k) or IRA count as income.
- Fees: fund and advisory costs reduce the return you actually keep.
- Uneven returns: a bad first few years hurts far more than the same losses late.
- Social Security and pensions: they lower what you need to pull from savings.
- One-off costs: a roof, a gift to a child, a health surprise.
Which input do people get wrong most often?
The expected return. After years of watching a tech stock climb, it's tempting to type 8% and see a result that never ends.
Try three returns, a low, a middle and a high one, and plan around the low one. Also leave inflation above zero, since a zero turns this into a different question.
Kestrel Bay Retirement Advisors: common questions
How accurate is a retirement withdrawal calculator?
No, it's an illustration, not a forecast. It assumes one steady return and one steady inflation rate every year, and real markets don't behave that way. Use it to compare withdrawal amounts side by side, then test the result against taxes, Social Security and a few bad early years.
Which expected return should I enter?
Pick a cautious number you could live with, then try a lower one too. For illustration this page uses 4.5% a year. Returns change from year to year and investing involves risk, including loss of principal, so look at the spread between your results, not one answer.
What inflation rate should I use?
Enter your best long-run guess for inflation and nudge it up once to see the damage. This calculator raises each year's withdrawal by that rate, so the example uses 2.5%. Higher inflation shortens the result because the same lifestyle costs more every year.
Can I use this calculator if most of my savings is company stock?
Yes, as long as you treat the savings figure as what's left after selling and paying tax. RSU vesting, ESPP sales and option exercises all create tax bills. Enter the after-tax amount you'd really hold, or run two versions of the balance.
What should I do after I get my result?
Write down the result, then check it against your tax picture. Ask which accounts the withdrawals would come from, what selling concentrated stock would cost, and what Social Security adds. Kestrel Bay Retirement Advisors reviews those pieces together on a video or phone meeting if you send a request.
This information is general education only and does not account for your specific circumstances, goals or finances. It is not investment, tax or legal advice. Investing involves risk, including the possible loss of principal. Before making any financial decision, consult a qualified professional about your own situation.