FIRE — financial independence, retire early — reduces to a single question: do your investments generate enough to cover your living expenses? Net worth is the closest thing to a scoreboard for that question. Track it consistently and you can see exactly how far you are from your target, whether you’re accelerating or stalling, and which levers are actually moving the number.
This guide covers how to set your FIRE target, what a net worth tracker should actually track, how savings rate maps to your timeline, and the pitfalls that make people misread their own progress.
Start With Your FIRE Number
Before tracking progress, define the finish line. The standard rule of thumb in the FIRE community is the 4% rule: a portfolio can plausibly sustain annual withdrawals of about 4% of its starting value over a long retirement. Flip that around and you get your target:
FIRE number ≈ annual expenses × 25
For example, if your household spends $48,000 a year, your rule-of-thumb target is $1.2 million in invested assets. Spend $70,000, and it’s $1.75 million. Two things to keep in mind:
- It’s based on expenses, not income. Cutting $500/month of permanent spending shrinks your target by $150,000 — often a bigger lever than earning more.
- It’s a rule of thumb, not a guarantee. It comes from historical US market studies, and plenty of people use 3.5% (×28.5) for a longer or more conservative retirement, or 4.5% for a flexible one. Pick a number, write it down, and refine it later.
Your net worth tracker’s job is to show the gap between where you stand and that number — and how fast it’s closing.
Build the Tracker: What to Include
A net worth tracker is just a dated list of everything you own minus everything you owe. A spreadsheet works fine; so do apps like Empower Personal Dashboard (free, strong on investments), Monarch Money, YNAB, or Copilot Money, which pull balances automatically from linked accounts.
Whichever tool you use, structure it so you can see two numbers separately:
- Total net worth — all assets minus all liabilities: cash, brokerage and retirement accounts, home equity, vehicles if you care to include them, minus mortgage, student loans, cards, and other debt.
- Invested (FIRE-relevant) net worth — only the assets that can actually fund withdrawals: brokerage accounts, retirement accounts, HSA, cash beyond your emergency fund.
The distinction matters because your FIRE number compares against the second figure, not the first. Home equity makes total net worth look great, but you can’t sell 4% of your kitchen each year to buy groceries. Tracking both keeps you honest: total net worth for overall financial health, invested net worth for FIRE progress.
Update monthly, on the same day each month. Weekly is noise; quarterly hides problems for too long.
Savings Rate: The Number That Sets Your Timeline
The counterintuitive math of FIRE is that your timeline depends far more on your savings rate — the share of after-tax income you invest — than on your income or your returns. A high savings rate attacks the problem from both ends: you accumulate faster and you prove you can live on less, which lowers the target itself.
Here’s the standard rule-of-thumb table, assuming you start from zero, earn roughly 5% real (after-inflation) returns, and retire at the 4% rule. Treat it as a compass, not a schedule:
| Savings rate | Approx. years to financial independence |
|---|---|
| 10% | ~51 |
| 20% | ~37 |
| 30% | ~28 |
| 40% | ~22 |
| 50% | ~17 |
| 60% | ~12.5 |
| 70% | ~8.5 |
The pattern worth internalizing: going from 10% to 20% buys you about 14 years; going from 50% to 60% buys about 4.5. Early improvements to a low savings rate are enormous. Add a “savings rate this month” row to your tracker — invested amount divided by after-tax income — and watch it alongside net worth. Net worth tells you where you are; savings rate tells you when you’ll arrive.
What to Review Each Month (and What to Ignore)
A monthly tracker review should take fifteen minutes. Look at:
- Invested net worth vs. your FIRE number — express it as a percentage. “31% of the way” is more motivating and more informative than a raw dollar figure.
- Contributions this month — the part you control. In any single month, market movement usually dwarfs your contributions in either direction; over a decade, contributions and compounding dominate. Judge yourself on contributions, not on the market’s mood.
- Savings rate trend — is the 3-month average holding, rising, or slipping?
- Liability balances — high-interest debt shrinking on schedule?
And deliberately ignore: daily portfolio swings, individual holding performance (that’s a portfolio-review question, quarterly at most), and comparisons to anyone else’s number. A market correction can erase a year of contributions on paper — for example, a $400,000 portfolio dropping 10% wipes $40,000 off your net worth in a month where you did everything right. If your review focuses on contributions and savings rate, that month still reads as a win, which is exactly the mindset that keeps people investing through downturns instead of selling out of them.
Common Pitfalls That Distort Your Progress
- Counting your primary home toward your FIRE number. Track the equity in total net worth, but fund your withdrawal math from invested assets only (unless your plan explicitly includes downsizing — then model the downsize as a future event).
- Forgetting taxes on pre-tax accounts. A traditional 401(k) dollar is worth less than a Roth or brokerage dollar after taxes. You don’t need precision here, but if most of your portfolio is pre-tax, consider padding your FIRE number by 10–15% or tracking a rough after-tax estimate.
- Changing methodology silently. If you decide to start including your car, or switch from Zillow’s estimate to purchase price for your home, note it on that month’s row. Otherwise future-you will misread a methodology change as a windfall or a loss.
- Chasing the tracker instead of the inputs. The tracker is a measurement, not a strategy. If the number stalls, the fixes live upstream: income, spending, and contribution automation.
Getting Started This Week
- Open a spreadsheet or an aggregator app and list every account with its current balance — assets and debts. That’s your baseline.
- Calculate your FIRE number: last 12 months of spending × 25. Rough is fine; refine later.
- Add three computed rows: total net worth, invested net worth, and percent-to-target.
- Put a monthly 15-minute recurring event on your calendar to update it.
- After three months, add the savings-rate row and look at your first trend line.
The first data point is the hardest and the least informative — net worth tracking pays off in the trend, not the snapshot. Twelve months from now, the line on that chart will tell you more about your path to financial independence than any calculator can today.