Life Trajectory: Net Worth and Cashflow Forecast Calculator

Today's dollars

Real growth = (1 + growth) / (1 + inflation) - 1

Every amount is in today's dollars, so $1 million at 70 means what $1 million buys now. Each growth rate you enter is converted to a real rate with your inflation assumption. Loans and cost basis are fixed in dollars, so a fixed payment shrinks in real terms each year. Switch to future dollars to see the larger numbers your statements will show.

Each year

Income comes in: salary with raises until you retire, bonus and stock pay, side income, pension, Social Security from your claiming age, rental cash flow, business distributions. 401(k) contributions follow the 2026 limits with catch-ups and the employer match. Then federal and state income tax are figured on the full return with our tax engines, plus Social Security and Medicare tax and self-employment tax. Spending, rent or home costs, child costs, life events and debt payments come out.

Saving and drawing down

Money left over first fills your emergency fund, then is invested in your brokerage account (or a new one at your assumed return). A shortfall is drawn from cash first, then taxable accounts (taxing the gain), then pre-tax accounts (taxed as income, grossed up for the tax, plus the 10% early-withdrawal penalty before 59 1/2 except a 401(k) after retiring at 55 or later and up to $10,000 from an IRA for a first home), then Roth and HSA money (assumed to come from contributions first, so no penalty). If everything runs out, the gap is shown as debt so the problem is visible.

Taxes stay current

Federal brackets, the standard deduction, contribution limits and the Social Security wage base all rise with inflation each year. Applying 2026 law to today's-dollar amounts therefore gives the right tax in every year without guessing future law.

Sales and life events

Selling a property or business pays off its loan and taxes the gain at long-term capital gains rates, with the $250,000 home exclusion ($500,000 married). Buying a home moves the down payment and closing costs out of savings (any savings in your withdrawal order, or cash and brokerage only, as you choose) and adds the home and its mortgage, with private mortgage insurance under 20% down until the loan reaches 80% of the price. A divorce splits every asset and debt by your share. Each event can be switched off to see what it costs.

Retirement years

Social Security is entered at full retirement age and adjusted for the age you claim: 5/9 of 1% less for each of the first 36 months early and 5/12 of 1% for each month beyond, or 8% more a year for waiting up to 70. Required minimum distributions start at 73 (75 for anyone born 1960 or later) using the IRS Uniform Lifetime Table. Roth conversions can fill a federal bracket each year until then. Health insurance costs a premium from retirement to 65, then Medicare, with IRMAA surcharges figured from income two years earlier. After a partner's death you keep the larger of the two Social Security benefits (a survivor benefit taken before survivor full retirement age is reduced), file jointly that year, and inherit their accounts.

Range of outcomes

The steady forecast assumes every year earns its average return. The range of outcomes runs your whole plan through 1,000 simulated markets instead: each year one random shock moves all your investment and retirement accounts together around their expected returns, with the yearly ups and downs you choose, and home values swing about 5% a year on their own. The chance your money lasts is the share of runs that never run short. When it is below 80%, we test single changes (saving more, spending less in retirement, retiring later, claiming Social Security later, higher returns) against the same markets to find the smallest that gets you there.

Scenarios and peers

Copy your plan into up to three scenarios and change anything to compare them side by side, with the differences listed. Your rank uses the Federal Reserve's 2025 Survey of Consumer Finances: published medians and averages by age of the head of household, and the 10th to 99th percentiles of net worth, income and retirement accounts, which we computed from the survey's public data with the Fed's method (each figure averaged over the survey's five data replicates). A value between two percentiles is placed on a straight line between them.

Cash flow

Each year's money in (pay, benefits, rents, business income, windfalls and sales, plus what you take from savings or borrow) always equals money out (taxes, living costs, housing, children and college, health care, events, debt payments, and what you save). Your own retirement contributions count as saved. Required distributions you do not spend are reinvested and left out of both sides.

After tax and independence

The after-tax view subtracts the tax you would still owe on pre-tax accounts and unsold gains. Financial independence is the first year your investments times the safe withdrawal rate cover that year's spending; Coast FI is the first year your investments could grow, with no more saving, to the target by retirement.

How do I calculate my net worth?

Add up what you own (cash, investments, retirement accounts, the market value of your home, other property, a business you own, vehicles) and subtract everything you owe (mortgage, student loans, car loans, credit cards). The calculator does this for every year of your life, then shows how saving, growth and life events change it.

What is a good net worth by age?

The Federal Reserve's 2025 Survey of Consumer Finances puts median family net worth at about $33,000 under age 35, $156,000 at 35 to 44, $254,000 at 45 to 54, $412,000 at 55 to 64 and $431,000 at 65 to 74. Averages are far higher because a few families hold a lot. A more useful test is whether your forecast reaches financial independence by the age you want to retire.

How much does college really cost my net worth?

More than the tuition. In our mid-career couple example (two children three years apart, public in-state college at $25,850 a year, partly paid from 529s), college lowers net worth at 95 by about $1,119,254 in today's dollars, because the money spent would otherwise have kept growing for decades. The same household reaches $4,071,084 at retirement.

When should I claim Social Security?

Each year you wait between 62 and 70 raises your benefit for life: claiming at 62 pays 70% of your full benefit (with a full retirement age of 67) and waiting until 70 pays 124%. Waiting pays more in total if you live past about 80 to 81. For couples, the higher earner waiting also raises the survivor benefit. The calculator compares claiming at 62, 67 and 70 inside your whole plan, including taxes and how long your savings last.

How sure is this forecast?

Not very, and no forecast is. Returns, inflation and your own life will differ from any assumption. That is why the calculator also shows a range: 1,000 simulated markets, the chance your money lasts, and how much bad markets in the first years of retirement hurt. A plan that lasts in 80% to 90% of markets, and that you update every year or two, is a sound place to be.

Is my data private?

Yes. The forecast runs entirely in your browser. Plans are saved only on your device, downloads are made in your browser, and a share link keeps the plan after the # in the address, which browsers never send to a server. We never see your numbers.

Why are the numbers in today's dollars?

Because a forecast in future dollars looks better than it is: at 2.5% inflation, $1 million in 40 years buys what about $370,000 buys today. Showing today's dollars keeps every year comparable with your life now. You can switch to future dollars at any time.

How accurate is a net worth forecast?

It shows where your current plan leads if returns, raises and inflation match your assumptions, which they will not exactly. Use it to compare choices (buy or rent, retire at 62 or 67, a bigger wedding or a bigger down payment) rather than as a promise. Markets go up and down; a steady average return hides that, so leave room for error.