Finance & Money · 等额本金 · Updated 2026-10-25
What Is Equal Principal Payment?
Definition
Principal is split evenly across months (P/n) plus interest on the remaining balance, so payments start high and decline. Saves interest at the cost of higher early payments.
Formula
Payment_k = P/n + (P − (k−1)×P/n) × r
Worked Example
First payment 5,278 (2,778 principal + 2,500 interest), total repayment 1.451M vs 1.518M for equal installments.
Common Misconception
"Equal principal always saves money, so pick it blindly" - the savings cost hundreds more per month early on; if that squeezes your emergency fund, it is a bad trade. At very low rates (e.g. housing-fund 2.6%) the gap is small - choose by cash-flow preference.
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