Free Online Loan Calculator — Monthly Payments & Amortization

Calculate monthly payments, total interest, and full amortization for mortgages, auto loans, personal loans, and more. This free loan calculator supports extra payments and shows you exactly how much you'll pay over the life of the loan.

What Is a Loan Calculator?

A loan calculator helps you estimate your monthly payment and total cost of borrowing before you commit to a loan. By entering the loan amount, interest rate, and term, you get an instant breakdown of how much goes toward principal versus interest each month.

Whether you're buying a house, financing a car, or considering a personal loan, this tool gives you the numbers you need to make informed financial decisions.

How to Use This Loan Calculator

1. Enter the loan amount — The total amount you want to borrow (e.g., $250,000 for a mortgage).
2. Enter the annual interest rate — The yearly rate your lender charges (e.g., 6.5%).
3. Set the loan term — How long you have to repay, in years or months (e.g., 30 years).
4. Optionally add extra payments — See how additional monthly payments reduce your interest and shorten your term.
5. View instant results — Monthly payment, total interest, and total amount paid update in real time.

Key Features

Feature	Benefit
Monthly payment calculation	See exactly what you owe each month
Total interest breakdown	Know the true cost of borrowing before you sign
Extra payment support	Discover how extra payments save you money
Year/month toggle	Enter terms in the format that makes sense for your loan
Copy results	Save the breakdown to your clipboard with one click
Privacy-focused	All calculations happen locally in your browser

Understanding Loan Math

Monthly Payment Formula

The standard amortization formula calculates a fixed monthly payment:

M = P × [r(1+r)^n] / [(1+r)^n − 1]

• M = monthly payment
• P = principal (loan amount)
• r = monthly interest rate (annual rate ÷ 12 ÷ 100)
• n = total number of payments (months)

For example, a $250,000 loan at 6.5% for 30 years:

• r = 6.5 ÷ 100 ÷ 12 = 0.005417
• n = 30 × 12 = 360
• M = $1,580.17/month

How Extra Payments Work

Extra payments go directly toward reducing the principal balance. Since interest is calculated on the remaining balance, every extra dollar you pay reduces future interest charges. Over the life of a 30-year mortgage, even a small extra payment can save tens of thousands of dollars.

Principal vs. Interest

In the early years of a loan, most of your monthly payment goes toward interest. As the balance decreases, more of each payment goes toward principal. This is called amortization.

Loan Type Comparison

Loan Type	Typical Amount	Typical Rate	Typical Term
Mortgage	$200K–$500K	5–7%	15–30 years
Auto Loan	$20K–$40K	4–8%	3–7 years
Personal Loan	$5K–$50K	6–20%	1–7 years
Student Loan	$20K–$100K	3–7%	10–25 years

Real-World Use Cases

Home Buying

Before house hunting, calculate what your monthly mortgage would be at different price points. Adjust the term and rate to find a comfortable payment range.

Auto Financing

Compare dealer financing vs. bank loans. A lower rate on a shorter term often saves more than a longer term with a slightly higher rate.

Debt Consolidation

Thinking about consolidating credit card debt into a personal loan? Calculate the total cost to see if it actually saves you money.

Early Payoff Planning

Use the extra payment feature to see how adding even $100/month to your mortgage can shave years off your loan and save thousands in interest.

Tips for Saving on Loans

Tip	Explanation
Shorter term = less interest	A 15-year mortgage costs more per month but far less in total interest than a 30-year.
Shop rates	Even a 0.5% difference in rate can save thousands over the life of the loan.
Make biweekly payments	Paying half your monthly amount every two weeks results in 13 monthly payments per year instead of 12.
Round up payments	Round your payment up to the nearest $50 or $100 — the extra goes straight to principal.
Avoid extending terms	Refinancing to a longer term lowers monthly payments but increases total interest.

Loan Amortization Example

Detail	Value
Loan Amount	$250,000
Interest Rate	6.5%
Term	30 years (360 months)
Monthly Payment	$1,580.17
Total Interest	$318,861
Total Paid	$568,861
With $200/mo extra	Saved $96,353 in interest, paid off in ~24 years

Frequently Asked Questions

How is the monthly payment calculated?

The monthly payment is calculated using the standard amortization formula, which ensures equal payments over the life of the loan. Each payment covers the interest due for that month, with the remainder going toward reducing the principal.

What happens when I make extra payments?

Extra payments reduce your principal balance faster. Since interest is calculated on the remaining balance, a lower principal means less interest accrues. This shortens your loan term and reduces total interest paid.

Does this calculator work for mortgages?

Yes. This calculator works for any fixed-rate amortizing loan, including mortgages, auto loans, personal loans, and student loans. For adjustable-rate mortgages (ARMs), the results apply only to the initial fixed-rate period.

Is the interest rate annual or monthly?

Enter the annual interest rate. The calculator automatically converts it to a monthly rate for the payment formula. For example, 6.5% annual becomes 0.5417% monthly.

Can I use this for variable-rate loans?

This calculator is designed for fixed-rate loans. For variable-rate loans, you can estimate payments for each rate period separately, but actual costs may change when the rate adjusts.

Does this tool store my financial data?

No. All calculations happen entirely in your browser. No loan amounts, rates, or personal data are sent to any server.