Exactly how we turn your numbers into a plan

Our defaults are sensible starting points, not rules. Your investment mix, inflation, spending, retirement ages, Social Security timing, and tax settings are all editable, and your projection updates the moment you change it.

We pick reasonable defaults grounded in market history so a brand-new plan is useful on day one. But this is your plan: tune any input to match your situation, and the numbers follow.

There's a single projection engine behind everything you see. We work hard to make it fast and inexpensive to run - but never at the cost of accuracy. You'll never get one number on one screen and a different number on another.

And we don't stop at a single blended return and a rough tax estimate. The engine models the details that actually move a retirement outcome - state taxes, RMDs, Medicare (IRMAA) surcharges, ACA subsidies, Social Security timing, and Roth conversions - the kind of depth most consumer tools skip. The difference: all of it is visible, and every assumption is yours to change.

Real markets have good years and bad years, often in an unlucky order. So instead of a single guess, we run your plan through many simulated market futures - strong runs, weak runs, and everything in between.

Your success rate is simply how often your money lasts across all of those futures. A 90% success rate means your plan held up in 9 out of 10 simulated worlds. We show the typical (median) outcome alongside the better and worse cases, so you see the range, not just one rosy line.

Long-term returns start from broad market history: stocks higher, bonds lower, cash lowest. Inflation defaults to about 2.5% per year, in line with long-run targets. We sanity-check our defaults against the kinds of forward-looking assumptions leading professional planning platforms use, so your starting point is credible - not optimistic marketing.

Crucially, your plan's inputs aren't locked - adjust your situation and the projection re-runs against your numbers.

A retirement plan isn't one blended return - it's a mix of stocks, bonds, and cash spread across your accounts, each with its own growth and risk. We model that mix, so a stock-heavy 401(k) and a conservative cash account grow differently, the way they really would.

And the mix is yours to control: set each account's split of stocks, bonds, and cash yourself - or start from a sensible, age-appropriate default - and choose whether returns follow forward-looking or historical market assumptions. Change it and the projection re-runs against the mix you picked.

Retirement math lives and dies on the details, so we model the ones that matter: federal and state income taxes, required minimum distributions at the current ages, Social Security based on when you choose to claim, and Roth conversion strategies.

We keep these rules current as tax brackets, contribution limits, and required-distribution ages change - and your claiming age, conversion amounts, and spending are all yours to set.

Health care is often a retiree's largest expense, so we don't gloss over it. Before 65 we account for marketplace coverage and the subsidies you may qualify for; at 65 we switch to Medicare, including the income-based (IRMAA) surcharges that catch many retirees by surprise.

You can also plan for later-life costs like long-term care, so a realistic health picture is part of your number from the start - not a line item left for you to guess at.

A million dollars decades from now doesn't buy what a million buys today. By default we show results in today's purchasing power, so the figures mean something you can feel. Prefer to see the raw future amounts instead? Flip a single toggle.

To build your plan we track the things a plan needs: your accounts and balances, income and spending, and your profile. Sensitive information is encrypted at rest, and we never sell your data.

You can see exactly what we hold and how we handle it on our privacy page.