You do not need to read anything first. Open the app and you'll see a full example already filled in for a person named Alex, age 30. Change any field and the chart updates immediately.

Two ways to begin:

• Start from the example. Edit Alex's numbers to match yours, one field at a time. This is the fastest way to get a feel for how everything connects.
• Start fresh. Clear it out and enter your own life from scratch.

Either way, there's nothing to save or submit. The projection recalculates as you type.

Start with the basics at the top:

• Current age
• Retire at (the age you plan to stop working)
• Default return (the average annual growth of your investments, entered as a nominal rate, the raw ~7% figure often quoted for the stock market, before inflation)
• Inflation

Open Advanced when you want more control:

• Life expectancy (how far out the projection runs)
• Withdrawal rate (how much you pull from savings each year in retirement)
• Tax rate (a flat rate, applied so you can see an after-tax picture). The paycheck calculator works out what yours is today
• Leftover-income behavior (what happens to money left over each month: save, invest, pay down debt, or spend)
• Retirement city (optional; retire somewhere cheaper and living costs scale to that city)

Fill in as much or as little as you want. More detail means a truer picture.

• Assets. Add each account with its current balance and monthly contribution. You can set a per-account growth override if one account should grow at a different rate than your default, and an age for contributions to stop (defaults to your retirement age). The override is a nominal rate, the same basis as Default return. Account type also decides how retirement withdrawals are taxed: Roth, HSA, and Cash/Savings come out tax-free; Traditional IRA, 401(k), and Pension are taxed in full at your Tax rate; and Brokerage is taxed only on its gains, not the full withdrawal. Contributing to a Traditional IRA, 401(k), HSA, or Pension also reduces your taxable income for that year, up to whatever you earn. An HSA is the only account that is tax-free both going in and coming out — we model that, but not contribution limits or the medical-expense requirement. See what those medical costs actually look like on the healthcare page.
• Liabilities. Add each debt with its balance. For loans like a mortgage or car, set how many years are left so the balance pays down over time.
• Income. Add each income stream with its amount. Optionally give it a growth rate for raises, a start age, and an end age for when it stops. For Social Security, enter your estimated annual benefit from your ssa.gov statement at the age you plan to claim it. This calculator does not estimate the benefit for you, and it taxes Social Security differently: 85% of it counts as taxable income, versus 100% for every other income type here.
• Living expenses. Enter your monthly spending now. Optionally set a separate in-retirement amount if you expect to spend differently once you stop working.
• Life events. Add one-time or recurring events like a home purchase, an inheritance, tuition, or a wedding.

The chart is the main view. Assets stack up above the line. Debt sits below it. The gap between them is your net worth over time.

Around the chart:

• Summary numbers give you the headline figures at a glance.
• A sticky bar keeps the key numbers visible while you scroll.
• Click any year (or the sparkline) to open the detail for that year and see what’s driving it.
• FIRE milestones show FIRE and Coast FIRE, each marked reached at an age or not reached. Set Lean FIRE spend or Barista FIRE Yearly Income in Advanced to also see Lean FIRE and Barista FIRE.

If the projection finds a shortfall, it will tell you that you run out of money and roughly when.

Everything lives in your browser. There's no account and nothing is uploaded.

• Use Export to download your plan as a file.
• Use Import to load that file back later, or to move your plan to another device.

If you clear your browser data without exporting first, your plan is gone. Export if you want to keep it.

Enter your home’s full market value as a Real Estate asset, and add the mortgage separately under Liabilities (with a term, so it pays down). Net worth is assets minus debts, so your equity — value minus what you still owe — grows on its own from both appreciation and each mortgage payment. Do not enter your equity as the asset while also carrying the mortgage; that subtracts the loan twice.

Real estate is treated as illiquid: it counts toward your net worth but is never sold to fund retirement, so your withdrawals draw only from cash and investment accounts. Property tax, insurance, and upkeep have no separate field — add them as Housing living expenses (you can set a different in-retirement amount).

• You can’t delete or reclassify your last cash or savings account. The engine always needs one place to hold money.
• For a mortgage or car loan, set the years remaining. Without it, the loan will not pay down and it will drag on your net worth forever.
• In-retirement expenses are entered in your current city’s prices. If you set a retirement city, its cost-of-living multiplier is applied on top. Enter today’s prices and let the multiplier do the adjusting. Do not adjust them yourself, or you’ll count it twice. The multipliers are measured against a US average, not against your city, so if you already live somewhere unusually cheap or pricey, set the retirement amounts to match what you expect to spend.