Plan your finances with our comprehensive calculator suite. Calculate mortgage payments with insurance and PMI, estimate loan costs with extra payments, project investment growth with tax rates, and analyze ROI — all in one place.
Monthly loan payments are determined by the principal (amount borrowed), the annual interest rate, and the loan term. The standard amortization formula distributes payments so that early payments are interest-heavy while later payments pay down more principal. Understanding this helps you see why even a small rate reduction can save thousands over the life of a loan, and why extra payments toward principal accelerate payoff dramatically.
Compound interest earns interest on both the original principal and previously accumulated interest. Albert Einstein reportedly called it the eighth wonder of the world. The formula A = P(1 + r/n)^(nt) shows how your money grows over time. Starting early matters enormously: investing $200/month starting at age 25 vs. age 35 can result in nearly double the retirement savings, even with the same total contributions.
ROI measures the profitability of an investment relative to its cost. The basic formula is (Net Profit / Cost of Investment) × 100. While simple ROI is useful for quick comparisons, annualized ROI accounts for the time period and gives a more accurate picture when comparing investments of different durations. Always factor in all costs — fees, taxes, and opportunity costs — for a realistic ROI figure.