What we've changed in the model
We keep improving how the calculator simulates your plan. Each change here moved the answer the same plan gets, so if your number shifted without you changing anything, this is where to look. Newest first.
A saved plan keeps the result it showed the day you saved it. When one of these changes moves it, the calculator and your dashboard will tell you, and show what the same plan gets today. How the model works
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Older partners and unusual settings are read consistently
A partner aged 91 to 100 is now given their own lifespan from the life tables instead of being treated as 90, so a plan with a partner in that range can move. A partner older than the tables cover is held at the oldest age they do cover. A survival setting at or below 0 percent, or at or above 100 percent, is now read as the nearest meaningful setting instead of failing, and the tax card caps an extreme return at the same 500 percent the probability already used. A survival setting already between 0 and 100 percent keeps its exact value, so plans built with the calculator controls keep the same result.
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Money inputs are capped at realistic maximums
The calculator now caps the main money inputs at figures far above any real plan: $100 million of savings, $10 million a year each of contributions and spending, and $1 million a year each for a separate healthcare line and a partner's Social Security. This limits what a mistyped or crafted number can do and does not change how a plan is simulated. If one of your figures was above its cap, your plan is now simulated at the cap, and saving and reloading it uses the same capped value. Every plan within the caps is unchanged.
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Dividends and cash are taxed more like real accounts
While you are still saving, dividends in a brokerage account are now taxed at the rate that goes with your tax bracket: nothing in the 10% and 12% brackets, 15% in the middle brackets, and 20% at the top, instead of 15% for everyone. Cash and savings accounts are now taxed on interest of about 3% a year, as ordinary income, and no longer on stock dividends they would never pay. If you are in a lower bracket with brokerage savings, your odds may go up a little. If you are in a high bracket, or hold a lot of cash outside retirement accounts, they may go down.
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Your HSA can now pay some medical costs tax-free
If you listed a health savings account but did not enter healthcare costs separately, the model used to treat every dollar you took out of it as ordinary income, with a 20% penalty before 65. It now assumes 4% of your spending is out-of-pocket medical care, roughly what households 65 and older spend on it, and lets the HSA pay that part tax-free. This only affects paid-tier plans that include an HSA and no healthcare line. Expect smaller early-withdrawal penalties and lower tax in the first years of retirement, and confidence that is usually a little higher. Lifetime tax can go either way: because the HSA is spent earlier, your other accounts stay invested longer and some of that growth is taxed later. Plans without an HSA, or with a healthcare line already entered, do not change.
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Tax breaks for people 65 and older
Once you or your partner turn 65, the model now gives each of you the extra standard deduction for age, plus the temporary $6,000 senior deduction for tax years through 2028, which shrinks at higher incomes. Your federal tax in those years goes down, so plans for people already in their mid sixties or older, or retiring soon after, will usually look a little better. Plans that start retirement years from now mostly see the permanent deduction only.
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Social Security starts between 62 and 70
Nobody can start a Social Security retirement benefit before 62, but the model used to pay it from whatever age you typed, even 55. A claim age below 62 now starts at 62, and one above 70 starts at 70, the last age that earns a bigger check. Plans with a claim age before 62 will see lower confidence, because those early years of income were never real. Plans with a claim age after 70 may see a little more, since waiting past 70 never made the check any bigger.
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Market years now come from real history
Each simulated future is now stitched together from actual US stock and bond returns from 1928 through 2025, taken a few years at a time, instead of independent random years. That lets a bad stretch arrive together, the way the 1970s did, and keeps stocks and bonds moving together the way they really did in a given year. Every plan's numbers move with this one.
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Required withdrawals start at 73 or 75 depending on birth year
Required minimum distributions from pre-tax accounts now start at 73 or 75 for each account owner, based on the birth year their age implies, matching current law. Plans with large pre-tax balances and owners born in 1960 or later are the ones most likely to move.
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Fixed a shortfall in years with a required withdrawal
In a year with a required minimum distribution, the model could withdraw slightly less than the law requires, or commit to more than it needed. It now starts from the required amount and corrects any overshoot. The effect is small and only touches plans with pre-tax accounts.
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Fixed income and healthcare costs follow the right clock
Income that does not rise with inflation now loses buying power from today or from when it starts, whichever is later. Healthcare costs now grow from today and switch over at each person's own Medicare age. Plans with a fixed pension or annuity, or a healthcare line, are the ones that move.
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Taxes on taxable savings while you are still working
Interest and dividends in a regular taxable account are now taxed each year while you save, not only once you retire. Plans that hold a meaningful share of savings in taxable accounts will usually see somewhat lower balances.
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Required withdrawals can start before you retire
If you plan to keep working past the age required withdrawals begin, the model now takes those withdrawals from your pre-tax accounts, pays the tax on them, and reinvests what is left in a taxable account. This only affects plans that retire late.
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Contributions that do not rise with inflation lose buying power
If you say your yearly savings will stay at a fixed dollar amount, each year's contribution is now worth a little less in today's money than the year before. Plans that keep the default, savings that rise with inflation, are unchanged.
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Couples can choose how a surviving spouse inherits retirement accounts
A surviving spouse can now either roll pre-tax accounts into their own name, the default, or keep them as an inherited account. The choice changes when withdrawals are required and when the early-withdrawal penalty applies after the first death. Couples on a paid tier are the ones affected.
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The last year of the plan is funded for the part you live
The planning horizon used to round to a whole year, which made confidence jump in steps as ages crossed a boundary. The final year is now paid for in proportion to how much of it is lived. About half of plans will show a planning age one year lower, with no change to their odds.
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Couples' lifespans no longer follow the early market
A flaw in how random numbers were drawn tied each spouse's simulated lifespan to the market returns in the first years of the plan. Lifespans and markets are now drawn independently. Only couples are affected, and a plan can move either way.
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Account rules follow the age of whoever owns the account
The early-withdrawal penalty and the start of required withdrawals now use the age of each account's owner rather than the first person on the plan. Couples with an age gap and accounts in both names are the ones most likely to move.
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One consistent way to draw the range of outcomes
The browser and the server now use the same method to mark the middle and outer bands of the outcome chart. The bands can shift slightly. The chance your money lasts does not change.
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A surviving spouse files taxes as single
After the first death, the survivor now files as a single taxpayer from the following year, as the tax rules require, instead of keeping joint brackets for life. Couples will usually see more tax in the survivor years and somewhat lower confidence.
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Pensions and annuities end when their owner dies
A pension or annuity now stops, or steps down, at the death of the person it belongs to, unless you tell us it continues for a survivor. Couples who rely on one spouse's pension will usually see lower confidence.
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We started recording which version of the model ran your plan
Every saved plan now remembers which version of the model produced it. That is what lets us tell you when one of our changes, rather than one of yours, moved your number.