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Part of the CalcProMaster guides library · Updated September 2026
Every guide shows the formula, a worked example, the assumptions, and the honest limits of the math — then links the calculator that does it for you.
Three relationships drive every loan, mortgage and investment calculation in this section. First, amortization: a fixed payment splits each month into interest (charged on the remaining balance) and principal (the rest) — so the interest share is largest in month one and falls every month after. The EMI guide's computed table shows the split to the cent.
Second, compounding: money grows by (1 + r/n)nt — the frequency n matters almost as much as the rate r. At 8% for 10 years, $10,000 becomes $21,589 compounded annually but $22,553 monthly; the compound interest guide shows where that difference comes from and when it reverses for loans you owe.
Third, total cost vs monthly comfort: a mortgage stretched to 30 years halves the payment but nearly triples lifetime interest versus 15 years at the same rate. Every guide here returns to that tension, because it is the decision lenders' ads quietly skip. When a number matters — a prepayment, a refinance, an extra principal payment — compute it with your own figures rather than trusting a rule of thumb; the matching calculators exist precisely so you never have to.
The EMI formula, why early EMIs are mostly interest, prepayment strategy, and a full $50k / 5-year worked example.
The compounding formula, the Rule of 72, why frequency matters, and what $10,000 becomes at different rates and years.
P&I, taxes, insurance and PMI — the full monthly payment, amortization over time, and where the 28/36 guideline helps.
Loan EMI Calculator Compound Interest Calculator Mortgage Calculator