How do equal-payment and equal-principal mortgage calculations differ?

Equal-payment repayment keeps the monthly amount fixed under a fixed interest rate, while equal-principal repayment returns the same principal amount each month. For a 120000 loan over 12 periods, equal-principal repayment returns 10000 of principal per period, plus interest on the remaining balance. The resulting cash flows differ. Compare the chosen model with the actual contract before interpreting the monthly payment or total interest as a lender's schedule.

How does an annual mortgage rate of 3.6 percent become a monthly rate?

In this tool's fixed monthly-rate model, an annual rate of 3.6% divided by 12 becomes 0.3% per month. A term entered in years becomes a number of monthly periods; for example, 20 years becomes 240 periods. These figures are calculation examples rather than current lending rates. Use the actual contract's rate and term, and check whether its payment and interest conventions match the model before comparing the result.

Does the mortgage calculator's monthly payment include taxes and insurance?

This calculator's monthly payment includes principal and interest, but excludes taxes, insurance, and service charges. It assumes 12 monthly payments per year and displays monetary values to 2 decimal places. A lender that rounds each period or follows another interest convention can produce a slightly different schedule. Add the contract's other costs separately when planning a complete budget, rather than treating the displayed loan payment as every housing-related expense.

Mortgage calculator

Compare monthly payments, total interest and schedules for two repayment methods

Computed in your browser

Enter principal, whole-year term and contract annual rate. Results compare both repayment methods; the example rate is not a current quote.

Loan principal (CNY)

Loan term (1–40 years)

Contract annual rate (%)

3.5% is an example, not a current quote. Enter the annual rate from your offer or contract.

Repayment comparison

Equal total payment

Monthly payment: –
Total interest: –
Total repaid: –

Equal principal

First payment: –
Monthly decrease: –
Final payment: –
Total interest: –
Total repaid: –

–less interest with equal principal –higher first payment with equal principal

Monthly repayment schedule

Period	Payment	Principal	Interest	Balance

Example

Input

Principal: CNY 1,000,000 · Term: 30 years · Annual rate: 3.5%

Example result

Equal total payment: CNY 4,490.45/month and CNY 616,560.88 interest; equal principal: CNY 5,694.44 first payment and CNY 526,458.33 interest

The example assumes a fixed rate for 360 payments. The 3.5% input is illustrative, not a current market quote or recommendation.

Technical details & limits

Equal total payment uses P×r×(1+r)^n÷((1+r)^n−1). Equal principal repays P÷n principal each month and charges interest on the outstanding balance. The annual rate is divided by 12, with one payment per month and a fixed rate throughout. Taxes, insurance, fees, prepayment, penalties and rate resets are excluded. Calculations keep full precision while displayed amounts round to cents, so bank schedules that round each period can differ slightly.

About this tool

Enter principal, term and contract annual rate to compare equal-total-payment and equal-principal plans, including monthly payments, total interest, total repaid and a month-by-month breakdown. All calculations run locally in your browser.

Use cases

Compare early cash flow and lifetime interest for two common repayment methods before signing.
Sense-check a lender quote and spot differences in principal, term or rate assumptions.
Inspect how much principal and interest make up a payment and the balance after it.

How to use

Enter the actual loan principal in CNY, not the property price or a down-payment percentage.
Enter a whole-number term from 1 to 40 years and the annual rate from the offer or contract.
Compare payment, total interest and first-month burden, then switch schedule methods for monthly detail.

Input & output

Input: Principal above 0 and up to CNY 1 billion, a whole term of 1–40 years, and an annual rate of 0–100%.
Output: Summary figures for both methods and up to 480 rows of payment, principal, interest and balance.
Limits: Standard monthly payments at a fixed nominal annual rate only; rate changes, prepayment and extra costs are excluded.

Notes

Results are for comparison and checking, not approval, a quote or financial advice. Actual debits follow the lender contract, day-count rules and period-by-period rounding.

FAQ

How do equal-payment and equal-principal mortgage calculations differ?: Equal-payment repayment keeps the monthly amount fixed under a fixed interest rate, while equal-principal repayment returns the same principal amount each month. For a 120000 loan over 12 periods, equal-principal repayment returns 10000 of principal per period, plus interest on the remaining balance. The resulting cash flows differ. Compare the chosen model with the actual contract before interpreting the monthly payment or total interest as a lender's schedule.
How does an annual mortgage rate of 3.6 percent become a monthly rate?: In this tool's fixed monthly-rate model, an annual rate of 3.6% divided by 12 becomes 0.3% per month. A term entered in years becomes a number of monthly periods; for example, 20 years becomes 240 periods. These figures are calculation examples rather than current lending rates. Use the actual contract's rate and term, and check whether its payment and interest conventions match the model before comparing the result.
Does the mortgage calculator's monthly payment include taxes and insurance?: This calculator's monthly payment includes principal and interest, but excludes taxes, insurance, and service charges. It assumes 12 monthly payments per year and displays monetary values to 2 decimal places. A lender that rounds each period or follows another interest convention can produce a slightly different schedule. Add the contract's other costs separately when planning a complete budget, rather than treating the displayed loan payment as every housing-related expense.

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