Retirement Planning Software

A free retirement planner that models the whole household year by year — accounts, wages, Social Security, taxes, Medicare and health insurance — and then stress-tests the result against 2,000 market lifetimes. It runs in your browser, and it is running below.

Most tools in this category are one of two things: a single-question calculator that answers “what is 4% of my savings” in a page, or a full planning suite that wants an account first. This one is the second kind of engine with none of the first kind’s ceremony. What follows is the inventory — what it models, what it optimizes, and what it will not do — so you can decide from the list rather than from an adjective.

What the projection models, year by year

The core is a year loop, not a formula. Each year of your plan is built from its own income, its own spending and its own tax return, and the balances that come out of it are what the next year starts with.

• Four account buckets — cash, taxable brokerage with its own cost basis, tax-deferred, and Roth — each with its own return assumption if you want one; tax-deferred is tracked per spouse so required distributions land on each person's own schedule.
• Wages with raises, employee and employer contributions, and the year contributions stop.
• Social Security for one or both spouses at any claiming age, with the spousal top-up and the survivor benefit after a death the plan models.
• Pensions, annuity income, rental properties with depreciation, and other income streams.
• Expense streams that each grow their own way — with inflation, at a rate you set, or flat — plus one-off events and expenses you mark as reducible.
• Real assets: a home, rentals, and a sale in the year you choose.

The tax engine underneath it

Retirement planning is mostly a tax problem, so the tax side is where most of the engine is. Every year is taxed: federal ordinary brackets and the standard deduction, long-term capital gains at their own rates, the taxable share of Social Security, and income tax for all 50 states. Required minimum distributions arrive on the current IRS schedule, computed per person off the prior year’s balance.

Health cover is modeled as the constraint it actually is. Before 65 the ACA premium tax credit is computed from that year’s MAGI, cliff included; from 65 the Medicare premium arrives with IRMAA priced off the two-year lookback, so a conversion you make at 63 shows up as a surcharge at 65. Early access has its own rules: the 10% penalty before 59½, the Rule of 55 for a 401(k) you separate from at 55 or later, and 72(t)/SEPP schedules under two of the three IRS methods.

Four things it searches for you

A Roth conversion schedule. Not a single-year what-if — a year-by-year ladder chosen against the whole remaining plan, aware of the bracket you are filling, the IRMAA tier you are about to cross, the ACA cliff in the bridge years, and the RMDs it is trying to shrink. A slider moves you along the measured schedules rather than guessing between them.

A claiming age. Every claiming-age combination for the household is scored — on lifetime tax, on the survivor floor it leaves behind, and on simulated plan success — rather than reduced to a break-even birthday.

A probability. 2,000 trials, stitched from three-to-seven-year blocks of real returns between 1926 and 2024 — stocks, bonds, T-bills and that year’s inflation together, so a high-inflation era arrives with the interest rates that really came with it. A trial succeeds only if every year of spending was funded.

A bond allocation. The simulator sweeps stock/bond mixes against your own assumptions and reports the one that scored best on a blend of success rate and median outcome, rather than leaving whatever split you started with as an unexamined default.

Months, not just years

Retiring in March is not the same as retiring in December, and the engine does not pretend otherwise. Retirement dates, Social Security start dates, milestones and the boundaries of income and expense streams land in their own month, and the year they land in is prorated — the salary, the health-cover months, and the coverage that starts or stops with the job.

Where it stops

The honest half of an inventory. It does not connect to your bank or brokerage: you type the balances, which is slower and is also why there is no aggregation service in the middle. It is not advice, and it does not know your circumstances — it is arithmetic you drive. It does not price insurance or annuity products; an annuity is modeled as the income stream it pays, not as a contract. Of the three IRS SEPP methods it implements two, and says so on the page about them. State taxes are modeled for retirement income, not for every state credit and local surtax. And it has no accounts, so a plan lives in the browser you built it in.

More on that last point on the private retirement planner page — where the plan is kept and what the browser computes. If you want the manual instead, the user guide covers every input in the tool.