| Scenario | Loan | Rate | Term | Frequency | Extra | What you should see |
|---|---|---|---|---|---|---|
| Standard mortgage-style | 250,000 | 7.50% | 30 years | Monthly | 0 | Total interest is large; payoff near full term. |
| Faster payoff | 250,000 | 7.50% | 30 years | Monthly | 100 | Lower interest and earlier payoff date. |
| Shorter term | 25,000 | 9.00% | 5 years | Monthly | 0 | Higher payment, much less total interest. |
This calculator uses the standard fixed-rate amortization payment formula:
- PV is the principal (loan amount, plus fees if rolled in).
- r is the periodic rate: annual rate ÷ payments per year.
- n is total payments: term years × payments per year.
- Each period: interest = balance × r, principal = payment − interest.
- Extra payments reduce principal faster and can shorten the payoff date.
- Enter your loan amount, annual rate, and term length.
- Select payment frequency and an optional start date.
- Add fees, and choose whether to roll them into the balance.
- Optionally add an extra payment per period to test payoff speed.
- Click Calculate to see results above the form.
- Use Download CSV or Download PDF for your records.
Tip: If your lender compounds differently than your payment frequency, treat results as estimates and confirm using lender disclosures.
Understanding what drives the payment
Your payment is mainly determined by the amount borrowed, the fixed interest rate, and the repayment term. A larger principal increases every period’s interest and required principal reduction. The rate controls the cost of borrowing per period, while the term spreads repayment across more or fewer payments. Fees, insurance, and taxes can be added as periodic costs, raising the all‑in payment without changing the loan balance. Payment frequency matters too; biweekly schedules create more payments per year and can reduce interest through principal reduction.
Rate sensitivity with a quick example
On a 5,000,000 loan repaid monthly over 5 years, moving from 14% to 16% can lift the payment by roughly 3–4%. That increase compounds over 60 payments, so total interest rises faster than the payment itself. When comparing offers, a small rate difference matters most early in the schedule, when the balance is highest and interest is calculated on a large base.
Term length trade‑offs
A longer term usually lowers the required payment, improving monthly affordability, but it increases lifetime interest because the balance declines more slowly. Shortening the term does the opposite: higher payment, lower total interest, and a faster payoff date. If your budget allows, compare two terms side‑by‑side and focus on total interest and payoff timing, not just the headline payment.
Interpreting the amortization table
Each row shows how a single payment is split. Interest is calculated on the beginning balance for that period; the remainder goes to principal. As the balance falls, the interest portion typically decreases and the principal portion grows, even though the payment stays fixed. This is why early payments feel “interest heavy” and why refinancing earlier can have a bigger impact.
Extra payments and payoff benefits
Extra payments go directly to principal, reducing future interest and shortening the schedule. Even modest extras, like 10,000 per period, can save several payments on medium‑term loans. In the results, watch the payments reduced and new payoff date to quantify the benefit. If you plan irregular extras, model an average extra amount and revisit it when income or rates change.
What is a fixed‑rate loan?
A fixed‑rate loan keeps the interest rate constant for the full term, so the scheduled payment per period stays the same. The split between interest and principal changes over time as the balance declines.
How is the payment calculated?
The calculator uses the standard amortization formula that converts principal, periodic interest rate, and number of payments into an equal payment. Optional fees and extra payments adjust the effective payment and the payoff timeline.
What’s the difference between interest rate and APR?
The interest rate prices the loan balance. APR can include certain fees and reflects a broader annualized cost. If a lender charges origination or mandatory fees, APR is typically higher than the stated rate.
How are extra payments applied?
Extra payments are applied directly to principal after the scheduled interest for the period. This lowers the remaining balance, reduces future interest, and may shorten the total number of payments needed to reach zero.
Why does the first payment feel mostly interest?
Interest is calculated on the starting balance. Early on, the balance is highest, so interest is larger. As the balance decreases, the interest portion falls and more of each fixed payment goes toward principal.
Can I change payment frequency?
Yes. Switching from monthly to biweekly increases payments per year and changes the periodic rate. That often accelerates principal reduction and can lower total interest, but confirm how your lender defines “biweekly” in practice.