Mortgage Calculator
Calculate monthly payments, total interest and full amortization schedules, comparing equal-payment and equal-principal loans
贷款参数
利率按钮只是常见档位的快捷填入，实际执行利率以银行审批为准，可随时手动改成任意数值。
About this tool
A mortgage is usually the largest and longest commitment a household makes. This tool puts the three tables a bank shows before lending onto the page:
- Payment and totals: monthly payment (or first payment), total interest, total repaid and interest as a share of principal
- Two repayment methods side by side: compare equal-payment and equal-principal loans on first and last payments and the interest gap, without rerunning the form twice
- Yearly schedule: annual totals for payment, principal and interest plus the remaining balance at year end, showing how interest dominates early and principal later
- Per-period detail: up to 360 rows, expanded or collapsed in one click
- Payment-to-income ratio: enter household income to see the ratio, colour-coded against the 50% threshold banks commonly apply
- Formula walkthrough: monthly rate, periods and the calculation are laid out step by step so bank figures can be checked
When to use it
- Estimating payment pressure before buying, then working back to an affordable loan and term
- Choosing between equal-payment and equal-principal for your cash flow
- Checking that a bank or broker quote matches the contract rate
- Setting a baseline before shortening the term or paying extra
- Filling in a household balance sheet or monthly budget
FAQ
- Which repayment method should I pick? Equal payment keeps the instalment fixed, easing early pressure at the cost of more total interest. Equal principal starts higher and falls every month, paying less interest overall. If the payment-to-income ratio allows it, equal principal saves more interest
- What rate do I enter? Commercial loans follow the loan prime rate plus or minus a spread, while housing fund loans use the published rate for the term. Enter the annual percentage written in the contract, not a decimal
- Why does the interest portion keep rising if the payment stays fixed? It does not: with equal payment, interest is charged on the remaining balance, so it falls each month while principal rises, keeping the total constant
- What if the result differs from the bank? Banks accrue daily, settle monthly and round the remainder, while this tool amortizes with the standard formula. Differences of a few cents to a few yuan are normal
Method comparison
| Item | Equal payment | Equal principal |
|---|---|---|
| Payment shape | Fixed throughout | Highest first, falling monthly |
| Total interest | Higher | Lower |
| Early pressure | Lower | Higher |
| Best for | Stable income and cash flow | Strong repayment capacity and early payoff plans |
| If paid off early | Much of the interest already paid | Principal falls faster, less interest remains |