Mortgage Calculator · Equal Payment & Equal Principal
Free mortgage calculator supporting equal payment and equal principal repayment. Instantly see monthly payment, total interest, total repayment and full amortization schedule.
Overview
A mortgage is usually the largest long-term liability for a household. This tool computes monthly payment, total interest and full amortization for both equal-payment and equal-principal methods, using the standard formulas published by mainstream commercial banks. Change any input and results update instantly.
How to use
- Enter the loan principal in your local currency unit.
- Enter the annual interest rate in percent (e.g. 3.1 for 3.1%).
- Choose a term (1–30 years) and repayment method.
- Monthly payment, total interest and the full schedule are computed instantly.
Formula
Equal payment (fixed monthly payment): M = P × i × (1+i)^n / [(1+i)^n − 1] Equal principal (fixed monthly principal, less total interest): payment = P/n + remaining_principal × i Where P = principal, i = monthly rate = annual_rate / 12 / 100, n = term in months.
Common scenarios
Scenario 1 · 1,000,000 at 3.1% over 30 years, equal payment
Monthly payment ≈ 4,270.56; total repayment ≈ 1,537,000; total interest ≈ 537,000.
Scenario 2 · 1,000,000 at 3.1% over 30 years, equal principal
First month ≈ 5,361.11, last month ≈ 2,785.21; total interest ≈ 466,000 — lower than equal-payment, but heavier upfront cash outflow.
Scenario 3 · Early repayment
If you plan to repay within 5–10 years, the interest difference between the two methods narrows. Consider future income, alternative investments and early-repayment penalties before choosing.
FAQ
Which is better, equal payment or equal principal?
Equal principal incurs less total interest because principal is paid down faster, but monthly payments start much higher. Choose equal payment for stable cash-flow, equal principal if you can bear heavier payments early to save interest.
How do I input an LPR-linked floating rate?
Enter the current effective rate (LPR ± spread). The tool assumes a fixed rate; re-run the calculation after each LPR adjustment to see the new payment.
Why does my bank app show a slightly different number?
Small differences come from rounding conventions. The underlying formula is identical; always defer to your signed contract.
Can I use it for housing-fund loans?
Yes. The formula is identical; just use the housing-fund interest rate. For combined loans, calculate each separately and sum.
How much do I save by early repayment?
As a rule of thumb, early repayment during the first third of an equal-payment loan saves the most interest. Check your contract for any prepayment penalty first.
Does this tool upload my loan data?
No. All computations run in your browser; no data leaves your device.
Related tools
Fixed Deposit Interest Calculator – Lump Sum & Monthly Savings
Calculate fixed deposit interest for lump-sum or monthly savings plans. Enter principal, term (3 months to 5 years), and annual interest rate to instantly compute maturity interest and total payout. Ideal for comparing bank deposit returns.
Credit Card Installment Calculator · Monthly Fee → Real APR · Newton IRR
Credit card installments often advertise a 0.6%/mo fee, implying ~7% a year — but the true APR is ~13.5%. This tool solves IRR via Newton's method to compute the real APR, plus monthly payment, total fee, and nominal-vs-real comparison. Supports monthly fee rate or total fee rate input.
Housing Fund Loan Calculator · Commercial / Fund / Combined Comparison
Compare three housing loan plans side by side — commercial only, fund only, combined — with monthly payment, total interest and total payment. Default fund rate 3.1% (first home, 5y+), commercial rate 4.5%. Runs locally.
Mortgage Prepayment Calculator · Shorten Term vs Reduce Payment
Enter your existing mortgage and a one-off extra payment to instantly compare the two mainstream plans — shorten the loan term or reduce the monthly payment — with new payment, remaining months, interest saved and months paid off early. Runs locally in your browser.