Loan guides
Plain-English explainers on how borrowing actually costs money. Each guide works through real numbers rather than rules of thumb, because the arithmetic of a loan is where the money is. Everything below was produced by our loan calculator and independently recomputed before publication.
How loan amortization works
The formula term by term, a worked month-by-month example, when principal finally overtakes interest, and why extra early payments save so much.
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How to compare loan offers
Why the headline rate is not the comparison, the three numbers that are, and how to work out whether discount points are worth paying.
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APR vs interest rate
What each number actually measures, what APR leaves out, and the cases where comparing APR will lead you to the wrong lender.
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Biweekly payments: what they really save
How paying half your mortgage every two weeks works, the exact saving on a worked loan, and the fees and pitfalls to avoid first.
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Refinance break-even point
How to work out the month a refinance pays for itself, why a shorter term can raise your payment and still save six figures, and when not to refinance.
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Start with the calculator
The quickest way to understand any of these guides is to watch the numbers move. Enter your own loan amount, rate and term in the loan calculator, then change one input at a time and watch the total interest line.
Reviewed by LoanCalcly Editorial · Last reviewed September 20, 2026. These guides are educational and are not financial advice. Spot an error? Tell us — see also our disclaimer.