How to enter your information correctly, what the numbers mean, and the assumptions the calculator makes behind the scenes. Jump to any topic below.
RetirFi needs no account and no login. Everything you enter saves automatically to your browser's local storage — your data never leaves your device unless you choose to back it up.
Because your plan lives in the browser, clearing your cache or switching to a different device or browser will lose it. Use Save Plan in the header to email yourself a restore link, or copy a shareable link to reopen the same plan anywhere.
On your first visit, a short guided wizard collects the essentials so you get a result quickly. You can load a fully worked example any time with Load Sample (the Alex & Jordan household) to see how a complete plan looks, then Reset to start from blank.
↑ Back to topThis is where most mistakes happen, and where a few simple rules keep your projection accurate.
⚠ The most common mistake. Enter loans only in the Liabilities section — never also as an expense.
Enter every loan (mortgage, car, student debt) in the Liabilities section. RetirFi amortizes each one and subtracts the payment from your cash flow automatically, then stops the payment once the loan is paid off. If you also list that payment as an expense, it gets counted twice — and your free cash flow and projection will be wrong.
Your Expenses section should hold only living costs — groceries, utilities, insurance, travel, and so on. Property tax and homeowner's insurance belong in the mortgage's escrow field, not as separate expenses.
On the retirement account in the Assets section, enable the employer-match option and set two numbers:
The match equals your contribution, capped at salary × match-up-to %, multiplied by the match %. So a 50% match up to 6% of a $100,000 salary — with you contributing at least $6,000 — adds $3,000 per year on top of your own contribution in every simulation year.
You can fund an account two ways: enter a flat dollar contribution directly on the account, or link it to an income source as a percentage of that income — so it scales with raises and stops when that income stops at retirement.
Either way, contributions are capped at the IRS annual limit for that account type (401(k) vs. IRA), including age-based catch-up amounts, so an oversized entry can't inflate your savings. Note that 529 college-savings accounts count toward your net worth but are excluded from retirement drawdown, since they're earmarked for education.
Add your home as a real-estate asset and link it to its mortgage in the Liabilities section. Your net worth then correctly nets the home value against the loan balance, and the home isn't treated as a liquid account. Only cash, brokerage, and retirement accounts are spent down in retirement — real estate stays on the balance sheet.
↑ Back to topTwo inputs drive the whole projection: your retirement age and your monthly income goal (your target retirement spending). The spending goal is required — without it, there's nothing for the simulation to fund. Enter it in today's dollars; RetirFi inflates it forward for you.
RetirFi estimates your benefit from your income and years worked using the SSA's PIA formula. It's a reasonable approximation, but your real benefit depends on your full 35-year earnings record. For accuracy, look up your number at ssa.gov/myaccount and switch the card to Manual to enter it directly.
Your claim age (62, 67, or 70) changes the benefit: claiming earlier means smaller checks, later means larger ones. The break-even between claiming at 62 and 70 is usually around age 80–82.
Turn on Include spouse to model two people. The plan then runs until the second death. When the first spouse dies, Social Security switches to the higher survivor benefit, household spending drops by a percentage you set, and tax filing status changes to single.
↑ Back to topThe bar at the top of the Monte Carlo tab sets your assumptions: dollar mode, retirement spending, lifespan(s), inflation, and number of simulations. More simulations means more precision but a slower run — 200 is a good balance, and 1,000 is the most precise. Press Run to simulate.
It's the share of simulated futures in which your portfolio doesn't run to zero before the end of your plan. An 85% result means your money lasted in 85 of every 100 simulated market histories. Financial planners commonly target 80–90% — higher isn't always better, since a 99% result often means you're underspending and will likely leave a large amount unspent.
Nominal dollars are the raw future numbers your statement will show. Real dollars are inflation-adjusted to today's purchasing power. At 2.5% inflation, $1 million in 30 years buys roughly what $480,000 buys today. Toggle between the two in the control bar.
Compare a scenario lets you build a "Scenario B" — retire earlier, claim Social Security later, or spend differently — and overlays it on your current plan so you can see the difference side by side. Plan Insights works backward from a target success rate to find your maximum safe spending, your earliest retirement age, and the single changes that move your odds the most.
↑ Back to topInstead of assuming one fixed return, RetirFi runs hundreds of futures with randomized year-to-year market shocks, capturing the sequence-of-returns risk that fixed-rate calculators miss. For the full explanation, see Monte Carlo simulation, explained.
In retirement, accounts are spent down tax-efficiently in this order: Taxable → Cash → Traditional → Roth. This preserves tax-advantaged growth for as long as possible. Pre-tax (traditional) contributions also reduce your taxable income while you're still working.
Required Minimum Distributions from traditional accounts begin at age 73 or 75 (per SECURE 2.0, based on your birth year) and are modeled automatically, including their tax impact. Take-home pay is derived from federal and FICA taxes for your filing status.
RetirFi is an educational tool, not financial advice.
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