Guides
Every calculator on SteadyCalc tells you a number. These guides explain the machinery behind the number — how amortization splits your payment, why APR and interest rate differ, what a 401(k) match is really worth — so you can judge the result instead of just reading it. Each guide is written to be read in a few minutes, uses worked examples with real arithmetic, and links to the calculator that lets you run your own figures.
How Loan Amortization Works
Why early loan payments are mostly interest, how the balance actually falls each month, and what extra principal payments really do.
Updated Jul 16, 2026
15-Year vs. 30-Year Mortgage: The Real Cost Difference
Compare monthly payments, total interest, and equity build-up on the same loan at both terms, and see when each one makes sense.
Updated Jul 16, 2026
Debt Snowball vs. Avalanche: Which Should You Use?
How the two payoff methods differ, what the interest gap looks like in real dollars, and how to pick the one you will actually stick with.
Updated Jul 16, 2026
How Credit Card Interest Actually Works
Daily compounding, grace periods, and why minimum payments barely move the balance — with the math shown step by step.
Updated Jul 16, 2026
APR vs. Interest Rate: What the Difference Costs You
What APR includes that the interest rate leaves out, how fees change the real cost of a loan, and how to compare offers fairly.
Updated Jul 16, 2026
How a 401(k) Employer Match Works
Match formulas, vesting schedules, and what a typical employer match is actually worth over a career once compounding does its job.
Updated Jul 16, 2026
PMI: What It Costs and How to Remove It
What private mortgage insurance costs, when lenders require it, and the specific ways to get rid of it once you have enough equity.
Updated Jul 16, 2026
How Big Should Your Emergency Fund Be?
A practical way to size an emergency fund from your real expenses, where to keep the money, and how to build it without stalling other goals.
Updated Jul 16, 2026
How these guides are written
Each guide starts from a question people actually type into a search bar, walks through the underlying math with concrete numbers, and is checked against the same formulas our calculators run. Where a topic touches regulation or official data — mortgage insurance rules, inflation history, retirement account limits — we point to the primary source rather than paraphrasing it from memory. You can read more about our process on the About page.