Financial Guides
Clear, practical explanations to help you understand the numbers behind everyday financial decisions. Each guide pairs with a free calculator.
- Author
- CentCompass
- Last Updated
- Reading Time
- 1 min read
Investing
- Compound Interest ExplainedWhy growth on prior growth eventually dwarfs your own contributions, how the formula works variable by variable, and what APY really means.
- Dollar Cost Averaging ExplainedInvesting a fixed amount on a fixed schedule, what the evidence says about it versus investing a lump sum, and when each approach makes sense.
Retirement
- How a 401(k) WorksContributions, the employer match, vesting, tax treatment and withdrawals — what actually happens inside a workplace retirement plan and where the money comes from.
- Roth IRA vs Traditional IRAPay tax now or pay it later. How the two accounts differ on deductions, withdrawals, RMDs and income limits — and which suits which situation.
Salary
- What Is FICA?The payroll tax that funds Social Security and Medicare, why it is charged on gross wages, and what the wage base and Additional Medicare Tax actually do.
- Gross vs Net Pay ExplainedWhy the salary you negotiated is not the money you receive, what each line on a pay stub actually is, and how to compare offers on the figure that matters.
Taxes
- Tax Brackets ExplainedHow US federal tax brackets actually work, why moving into a higher bracket never cuts your take-home pay, and how to read the rate schedule.
- Marginal Tax Rate vs Effective Tax RateTwo numbers describe your tax bill and they answer different questions. Here is which to use for decisions and which describes what you actually pay.
Real Estate
- What Is PITI?Principal, Interest, Taxes and Insurance — the four parts of a mortgage payment, why lenders judge you on all four, and how escrow actually works.
- What Is PMI?Private mortgage insurance protects the lender, not you. Here is what it costs, when it applies, and the three different ways to get rid of it.
- Fixed vs Adjustable Rate MortgageHow ARMs actually adjust, what the caps really protect you from, and the specific circumstances in which each type of mortgage is the better choice.
Debt
- Debt Avalanche vs Debt SnowballTwo ways to order your debt payoff. One is mathematically cheaper, the other is psychologically easier — and the research on which actually gets finished may surprise you.
Sources
How this page is produced
Editorial process. CentCompass is maintained independently, and this page is written and checked against the official publications listed above before it goes live. There is no separate editorial reviewer. This page was last checked on . See our editorial policy.
How the calculations work. Every result comes from a small, unit-tested calculation engine rather than a spreadsheet or a hardcoded table. Loans use the standard amortization formula, growth uses compound-interest math, income tax applies the federal progressive brackets, and payroll applies Social Security and Medicare rules. Our methodology sets out each one.
Where the figures come from. Tax brackets, standard deductions, FICA parameters, and contribution limits are stored once in a dated registry and read directly by the calculators — the same values appear in the text above, so the two can never drift apart. Each figure records its source, effective tax year, and review status on our data sources page.
Update policy. Regulatory figures are checked against their primary source when the IRS, SSA, or another authority publishes new values — typically each autumn for the following tax year — and again at the scheduled review date recorded for each dataset. Figures that have not been checked yet are marked as draft on the data sources page until that check is complete.
Educational purposes only — not financial, tax, or investment advice (disclaimer).