Setting the Dials

What the record actually says · six assumptions

The short version

If you read nothing else

DialPage defaultWhat I would setWhy
Inflation3%3%The 97-year average, and above today's forecasts
Return while investing7.9%6.5%Your runway is 10 years and 10-year forecasts are 4% to 6.5%
Return in retirement6.4%6.0%70/30 at today's bond yields
Withdrawal rate3.25%3.3%Between the historical floor and the forecast-based number
Plan through age95100Five more years costs 3.9%. Cheapest insurance on the page
Reach the money at59.559.5Retiring at 51 means the rule of 55 never applies to you
The one that matters most Nothing else on this page moves your answer like the return does. Run your plan at 8.5% and you retire at 53. Run it at 5% and you retire at 61. Same savings, same spending, same person. Eight years of your life sitting inside one box that nobody can actually know.

01Inflation

Page default 3% · leave it there

What the record says

What to do with that

Stay at 3%. It matches the long record, it sits above what the forecasters expect, and being wrong high here is the safe direction: it makes the plan ask for more, not less.

One thing the 3% hides. Retiree spending is weighted toward health care, which has run well above headline inflation for decades. If a big share of your later spending is medical, the real number for you is higher than the one on the news.

Set it to3%, and do not spend more time on it. Of the six dials this is the one most likely to be right already.

02Return while investing

Page default 7.9% · probably too generous for a 10-year runway

What history paid

1928 to 2024NominalAfter 3% inflation
US large-cap stocks9.9%6.7%
10-year Treasuries4.5%1.5%
Cash3.3%0.3%

That is the number everybody quotes, and it is real. It is also 97 years long, which is longer than the 10 years you actually have before you stop working.

What the forecasters expect from here

SourceUS stocksBondsHorizon
Vanguard, June 20264.2% to 6.2%10 years
Verus 20266.5%*4.8%10 years
Morningstar~7.0%~4.0%30 years

* an arithmetic average. See the first trap below, it is worth about 1.2 points.

Every one of them lands under the historical 9.9%, and they land there for the same reason: stocks are expensive relative to earnings right now, and starting valuation is the one thing that has any predictive power over a decade.

The honest counterpoint. These same 10-year forecasts have been too pessimistic for most of the last fifteen years. Vanguard has been publishing single-digit equity forecasts since roughly 2014 while US stocks compounded at well over that. Treat them as a reason to be careful, not as a prediction.
Set it to 6.5% as your working number, then check 5% and 8% before you trust the answer. Your accumulation window is exactly the 10 years these forecasts cover, so this is the one place where their pessimism deserves a hearing. If you want one number rather than three, use the lower one: saving too much is the recoverable mistake.

03Return in retirement

Page default 6.4% · close, but the bond half is knowable

The part you can almost look up

Bonds are the unusual case in finance where the future is nearly readable. The yield on the day you buy explains most of what a bond portfolio returns over the following decade. Today the 10-year Treasury pays 4.79% and the 30-year pays 5.25%. So the bond side of a retirement portfolio is worth roughly 4.8%, and that is not a guess.

Blending it

MixNominalReal
70 stocks / 30 bonds6.0%2.9%
60 / 405.8%2.7%
All bonds, a bridge portfolio4.8%1.7%

Built from 6.5% stocks and 4.8% bonds. Your 6.4% default is not wrong, it just quietly assumes stocks do a little better than the forecasters expect.

Where the page is too simple for your plan. You have described two different retirements stacked together: a bond-heavy bridge from 51 to 59.5, then 70/30 after. The calculator has one return box for the whole stretch, so it splits the difference. If the bridge really is bonds, the first eight years earn closer to 4.8% than 6.0%, and those are exactly the years where a bad number does the most damage.
Set it to 6.0% for a 70/30 retirement. Use 5.5% if you want the bond-heavy bridge years reflected in the single number, which for you is the more honest choice. That 5.5% is not a guess: it is the flat rate that produces the same answer as eight and a half years at 4.8% followed by thirty-five at 6.0%.

04Safe withdrawal rate

Cross-check only · but worth understanding

This box does not drive your number. It drives the cross-check, which exists so you can compare against calculators built on the 4% rule. Three separate bodies of research answer it and they do not agree.

One: US history, run forward

Two: forward-looking, run from today's valuations

Morningstar redoes this every year from current market assumptions rather than history. Their 2026 answer is 3.9% for 30 years at a 30% to 50% stock allocation. Their published series:

Year202120222023202420252026
Safe starting rate3.3%3.8%4.0%3.7%3.7%3.9%

Stretch the horizon and it drops: 3.5% at 35 years, 3.2% at 40. Yours is 44.

Three: the rest of the world

Pfau ran the same test across 20 developed countries from 1900 to 2015. Only five supported a 4% withdrawal. In eleven of the twenty it was under 3%. Japan's 1937 retiree could take 0.27%. Austria's 1914 retiree, 0.07%. The United States finished near the top of that table at about 4.0%.

That is the uncomfortable finding buried under the 4% rule. It is not a law of markets. It is the result for the country that won the century.

Set it to 3.3% for a 44-year retirement. That sits between the historical floor of 3.5% and Morningstar's forward-looking 3.2%, which is about as defensible as a single number gets. The page picks 3.25% on its own, so you can leave it alone.
But do not plan with it. A withdrawal rate is a rule for someone with no other income and no willingness to adjust. You have Social Security arriving mid-retirement and the flexibility to spend less in a bad year. Morningstar's own work shows flexible spending rules support starting rates as high as 5.7%. The rate is a sanity check, not a plan.

05Plan through age

Page default 95 · go to 100, it is nearly free

What the tables say

By that arithmetic, planning to 95 is already conservative and planning to 100 looks close to paranoid. Which would be the right conclusion if the two errors cost the same. They do not.

The asymmetry

Dying at 88 with money left over costs you some spending you could have enjoyed. Living to 97 with the account empty at 95 costs you your independence at the age you can least do anything about it. Those are not the same size mistake, so they do not deserve the same weight.

And here is the part that settles it. In your plan, moving the horizon from 95 to 100 raises the number you need from $4,889,327 to $5,077,987, a difference of 3.9%. Five extra years of certainty for less than four cents on the dollar, because money needed 55 years out discounts to almost nothing today.

Set it to 100. It is the cheapest insurance on this page. If you want the aggressive version, 95 is genuinely defensible and the whole difference is 3.9%.

06Age you can reach the money

You had this set to 55 · it should be 59.5

This one is not an assumption, it is a rule, and it does not go your way The rule of 55 lets you pull from a 401(k) without the 10% penalty, but only if you separate from that employer in or after the calendar year you turn 55. It keys off the year you leave, not the year you withdraw. Retiring at 51 means you never qualify, and you never qualify later either. That plan stays locked until 59.5.

The rule of 55, precisely

What that does to your bridge

Leaving at 51Years to bridgeNeeded outside the 401(k)
If the rule of 55 applied4$690,007
Reality, 59.58.5$1,377,198

Today's dollars, at $15,000 a month, at a 6% return.

That is double the bridge, and it is the single most useful thing on this page. It is also exactly what your taxable brokerage is for.

The escape hatch

A 72(t) lets you take substantially equal periodic payments from an IRA at any age with no penalty. The catch is real: payments must continue for five years or until 59.5, whichever is longer, and breaking the schedule triggers retroactive penalties plus interest on everything you already took. For a 51-year-old that is an 8.5-year commitment to a fixed withdrawal, locked in before you know what the market does.

Roth contributions, as opposed to earnings, come out any time tax and penalty free. That is bridge money most people forget they have.

Set it to 59.5. Set it to 55 only if you will actually still be working in the year you turn 55. Set it to your retirement age only if you have committed to a 72(t).

What the spread costs you

Your plan, three sets of assumptions

Retiring at 51 on $15,000 a month, $1,000,000 invested, $80,000 a year going in, Social Security of $6,243 from 67, spending it down by 95. All figures in 2036 dollars.

AssumptionsNeed at 51Will haveShort byEarliest
US history, 8.5% / 7.0%$4,300,392$3,634,917$665,47553
Page default, 7.9% / 6.4%$4,637,622$3,476,087$1,161,53555
My suggestion, 6.5% / 6.0%$4,889,327$3,132,492$1,756,83557
Forecasts, 5.0% / 4.8%$5,804,972$2,803,005$3,001,96761

Nobody knows which row is the real one. What you can know is that the honest answer to "when can I retire" is not a date, it is 53 to 61, and the way you shrink that range is by saving more and rechecking every year, not by picking a better number for the box.

The practical move Plan on the third row and be delighted by the first. If you plan on the first row and get the fourth, you find out at 53 with no working years left to fix it.

Two traps in the numbers

Both of them make things look better than they are

One: the average that is not the average

A portfolio that gains 50% then loses 50% has an average annual return of zero and has lost a quarter of your money. The average of the yearly numbers, the arithmetic mean, always overstates what you actually compound at, and the gap grows with volatility. For a stock portfolio it runs about 1.2 points.

So when a firm publishes 6.5% for US stocks, check which one it is. Verus's 6.5% is arithmetic, which compounds at roughly 5.3%. This calculator compounds, so it wants the lower one.

Two: the order of the returns, not just the size

Two retirees can earn the identical average return over thirty years and one runs out of money while the other dies rich. The difference is whether the bad years came first. Selling shares to live on in a down market takes out capital that never comes back, and no average return in any box on this page captures that risk.

It is why Morningstar's optimal withdrawal-rate portfolio is only 30% to 50% stocks rather than 70%, even though 70% has the higher expected return. And it is why hitting your number exactly, on the day, is not a safety margin. It is a coin flip you have arranged to be roughly fair.

Where this came from

Checked September 2026