| Year | Principal | Interest | Balance |
|---|---|---|---|
| 1 | $4,560 | $1,076 | $15,440 |
| 2 | $4,842 | $795 | $10,598 |
| 3 | $5,140 | $496 | $5,457 |
| 4 | $5,457 | $179 | $0 |
Educational tool. Not financial advice. Doesn't include origination fees, prepayment penalties, or insurance — actual APR and total cost may differ from amortization-only output.
Loan Calculator — Monthly Payment, Interest & Amortization
Enter your loan amount, interest rate, and term to see monthly payments. The stacked bar chart breaks down principal vs interest per year with a full amortization table.
How to calculate a loan
- Enter the loan amount, interest rate (APR) and term in years.
- The calculator produces a monthly payment and full amortisation schedule.
- Review the total interest paid — for long mortgages this often rivals the original principal.
- Model extra-payment scenarios to see how much time and interest you save by overpaying.
Common use cases
- Comparing loan offers from different lenders where the headline rate is similar but fees and term differ.
- Deciding whether to overpay a mortgage versus investing the extra cash elsewhere.
- Evaluating the true cost of a car loan before signing, including the depreciation that shadows the payments.
- Planning cash flow during a high-expense period where knowing the monthly payment matters more than the headline rate.
Frequently asked questions
Why does most of my early payment go to interest?
In a standard amortising loan, interest is calculated on the remaining balance. Early on the balance is high, so interest dominates. As principal shrinks, each payment sends more to principal — by the end, interest is a minor part of each payment.
Should I pick a shorter or longer term?
Shorter terms save substantial interest at the cost of higher monthly payments. Longer terms ease cash flow but pay much more interest. Run both numbers and pick the one that fits your budget without straining it.
Does APR include fees?
A proper APR includes mandatory origination fees and points, so two loans with the same nominal rate but different fees show different APRs. Always compare APRs, not nominal rates.
Is my data stored?
No. All calculations run in your browser.
About loan amortization
Loan amortization shows how each payment splits between principal and interest. Early payments are mostly interest; later payments are mostly principal.
- Monthly payment calculation
- Stacked bar chart by year
- Amortization schedule table
- Total interest over loan life
- Term from 6 to 120 months
- Export chart as PNG
Free. No signup. Inputs stay in your browser. Ads via AdSense (consent required).
Sources (2)
- U.S. Congress (1968). Truth in Lending Act (TILA). Public Law 90-321, 15 U.S.C. §§ 1601–1667f.
- Consumer Financial Protection Bureau (2024). Regulation Z — APR and amortization disclosures. 12 CFR § 1026.17 and Appendix J (actuarial method).
These are the original publications and regulations the formulas in this calculator are based on. Locate them by author and year on Google Scholar, SSRN, or the U.S. Government Publishing Office.