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Guides
Explainers for the concepts behind FinCalc's calculators — mortgages and PMI, loan payoff strategy, compound interest and retirement planning, paycheck deductions, and how to read an amortization schedule.
🏠 Mortgage guides
Related tool: Mortgage Calculator
How Mortgage Amortization Works
Why your payment stays fixed but the principal/interest split shifts every month, with a worked example.
Read guide →PMI Explained
What private mortgage insurance costs, when it's required, and the exact 78%/80% LTV removal thresholds.
Read guide →15-Year vs. 30-Year Mortgage
A worked side-by-side comparison of payment, total interest, and typical rate differential.
Read guide →Biweekly vs. Monthly Mortgage Payments
Why accelerated biweekly payments really work — one extra payment a year — with a worked $300,000 example.
Read guide →Mortgage Recast vs. Refinance
Two ways to lower your payment after a lump sum or a rate drop — how each works and when each wins.
Read guide →💳 Loan payoff guides
Related tool: Loan Payoff Calculator
📈 Retirement guides
Related tool: Retirement Calculator
How Compound Interest Works
The Rule of 72 shortcut and a worked example comparing compound to simple interest over 30 years.
Read guide →401(k) vs. IRA Contribution Limits
The difference between the account types and the exact 2026 IRS contribution limits, sourced to irs.gov.
Read guide →How Much to Save for Retirement
The 4% rule (25x expenses) from Bengen and the Trinity Study, plus age-based savings benchmarks.
Read guide →🧾 Paycheck guides
Related tool: Paycheck Calculator
📅 Amortization schedule guides
Related tool: Amortization Schedule