A plain-English financial library.

Net worth is everything you own minus everything you owe. It's the single most honest number for your financial progress — watch the trend over time more than the total on any given day.

Cash flow is the money coming in versus going out each month. Positive cash flow means you keep more than you spend, and that surplus is what funds every other goal you have.

An emergency fund is cash set aside for real surprises — a job loss, a medical bill, a car repair. It's what keeps one bad month from turning into credit-card debt.

A common target is around 20% of your take-home pay, but any consistent amount beats none. Start with what's realistic and raise it a little each time your income grows.

APR is the yearly cost of borrowing, shown as a percentage. A 24% APR credit card charges roughly 2% of your balance every month — which is exactly why unpaid balances grow so fast.

Paying only the minimum covers mostly interest, so the balance barely moves. Anything you pay above the minimum goes straight to the principal and shortens the payoff dramatically.

Pay the minimum on everything, then throw every extra dollar at your smallest balance first. Clearing whole debts quickly builds momentum and keeps you motivated.

Pay the minimum on everything, then attack the highest-interest debt first. It saves the most money mathematically, even if the early progress feels slower.

This is how much of your available credit you're using. Keeping it under 30% — and ideally under 10% — is one of the fastest ways to lift your credit score.

A 401(k) is a retirement account offered through your employer. You contribute straight from each paycheck, and the money grows invested until you retire.

Traditional accounts give you a tax break now and are taxed when you withdraw in retirement. Roth accounts are funded with money you've already been taxed on, but they come out completely tax-free later.

Many employers add money when you contribute — say, up to 4% of your salary. That's an instant 100% return, so contribute at least enough to capture the full match.

An expense ratio is the yearly fee a fund charges, as a percentage. The gap between 0.03% and 1% quietly costs tens of thousands over a career, so favor low-cost funds.

A target-date fund is a ready-made portfolio tied to the year you plan to retire. It automatically shifts from stocks toward bonds as you age — a simple, hands-off default.

A stock is a share of one company. An ETF is a basket of many companies bought in a single share, so one purchase spreads your money across dozens or hundreds of them at once.

An index fund simply tracks a whole market, like the S&P 500, instead of trying to beat it. It's low-cost, broadly diversified, and historically hard for the pros to outperform.

Don't put everything into one company or one bet. Spreading your money across many investments means no single loss can sink you.

Higher potential returns come with bigger swings along the way. The goal isn't to avoid risk entirely, but to take the right amount for how long you have to invest.

Your returns start earning returns of their own. Given enough time, this snowball ends up doing more of the work than the money you actually contribute.

Money grows slowly at first and then accelerates. The earlier you start, the more the later years explode — which is why time in the market matters more than timing it.

Saving protects money for the short term; investing grows it for the long term. You need both — cash for emergencies, and investments for the future.

Lasting wealth usually comes from several sources at once — retirement accounts, taxable investments, real estate, a business. Every one you add makes your finances sturdier.

Insurance, an up-to-date beneficiary list, and a basic estate plan make sure what you build actually reaches the people you intend.