Loan Repayment CalculatorMonthly Payment + Amortization

Lenders use a standard amortization formula to calculate fixed monthly payments on installment loans. The formula is:

M = P × r × (1 + r)^n / ((1 + r)^n − 1)

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

Example: A $250,000 mortgage at 6.5% APR over 30 years gives a monthly payment of about $1,580. Over the full term you'll pay roughly $319,000 in interest — more than the original loan amount.

Four main inputs determine your monthly payment and total interest cost:

• Interest rate. Even a 1% difference can mean tens of thousands of dollars over a 30-year mortgage. Shop around and improve your credit score before applying.
• Loan term. Longer terms reduce monthly payments but dramatically increase total interest. A 15-year mortgage costs much less in interest than a 30-year one.
• Principal (loan amount). Borrowing less is always cheaper. A bigger down payment lowers your principal and your monthly payment.
• Extra payments. Paying more than the minimum each month reduces principal faster, slashing total interest and shortening the loan.

Curious about strategies? Read our guide on how to pay off a loan faster, or see how much you should save each month to balance debt payoff with long-term savings.

Amortization is how a loan is paid off through equal monthly payments. Each payment is split between interest and principal, but the proportions change every month:

• Early payments are mostly interest because the balance — and therefore the interest charge — is highest at the start.
• Later payments are mostly principal because the balance has shrunk and less interest accrues.

The amortization schedule above shows this breakdown for every single month of your loan. Open it to see exactly how much interest vs principal you pay each month.

Every extra dollar you pay goes directly to principal. That reduces the balance interest is calculated on for every remaining month — so the savings compound.

Example: On a $250,000 mortgage at 6.5% over 30 years, paying just $200 extra per month saves about $95,000 in interest and pays the loan off roughly 7 years early.

Use the "Extra Monthly Payment" field above to model your own scenario — the calculator will show your interest savings instantly.

Here's how the same calculator handles three very different loans. Each example shows the monthly payment, the total interest cost, and how much you'd save by adding a small extra payment each month.

Example 1 — $10,000 personal loan at 10% for 5 years

The base monthly payment is about $212 and total interest is around $2,748. Add just $50 extra per month and you'd pay the loan off about 13 months early and save roughly $700 in interest — for less than $2 a day.

Example 2 — $30,000 auto loan at 7% for 6 years

The monthly payment is about $511 with around $6,827 in total interest. An extra $100 per month shortens the loan by roughly 14 months and saves close to $1,400 in interest. Choosing 5 years instead of 6 at the same rate would cut interest by another ~$1,200.

Example 3 — $250,000 mortgage at 6.5% for 30 years

The base monthly payment is about $1,580, but you'll pay nearly $319,000 in interest over the life of the loan — more than the original principal. Adding $200 extra per month saves about $95,000 in interest and pays the mortgage off about 7 years early. Plug your own numbers in above to see your version of this scenario.

This free online loan calculator takes four inputs — loan amount, annual interest rate, term, and an optional extra monthly payment — and instantly returns your monthly payment, total interest paid, total cost, and a full month-by-month amortization schedule. It works for any fixed-rate installment loan, including auto loans, personal loans, student loans, and home loans.

Behind the scenes it uses the same amortization formula every bank uses, then simulates each month of the loan to show how your balance, principal, and interest change over time. No data is sent to a server — every calculation runs in your browser.

Whether you're trying to pay off a personal loan, car loan, or mortgage early, the strategy is the same: get more money to principal each month. Here are the most effective ways to pay off a loan faster:

• Make biweekly payments. Paying half your monthly payment every two weeks adds up to one extra full payment per year.
• Round up your payment. Rounding $487 up to $550 sends ~$63 extra to principal every month with no real budget pain.
• Apply windfalls. Tax refunds, bonuses, and cash gifts go a long way when applied as lump-sum principal payments.
• Refinance to a lower rate. If rates have dropped, refinancing can cut years off your loan and reduce total interest dramatically.
• Switch to a shorter term. Moving from a 30-year to a 15-year loan increases the monthly payment but slashes total interest.

Use the extra monthly payment field above to model any of these strategies and see exactly how many months and how much interest you'd save.

For a fixed-rate loan, monthly interest is simply your current balance × the monthly interest rate (annual rate ÷ 12). Each month, the lender charges interest on whatever you still owe, then applies the rest of your payment to principal. Because the balance shrinks every month, the interest portion shrinks too — which is why later payments wipe out principal much faster than early ones.

To estimate total interest on any loan — auto loan, personal loan, student loan, or small business loan — enter the loan amount, APR, and term above. The total interest figure shows exactly how much the loan will cost you on top of the principal.

Five quick steps to get an accurate repayment estimate:

1. Enter your loan amount — the principal you plan to borrow.
2. Add the interest rate — use APR if you have it.
3. Set the loan term — in years or months (auto loans are usually 36–84 months, mortgages 15–30 years).
4. Optional: add an extra monthly payment — to see how much faster you can pay it off.
5. Review the results — monthly payment, total interest, payoff time, and the full amortization schedule update instantly.

• Compare auto loan offers — test 48 vs 60 vs 72-month terms to see total interest at each.
• Pay off a personal loan early — try $50, $100, or $200 extra per month to see months and interest saved.
• Plan student loan repayment — model standard vs accelerated payoff schedules.
• Estimate a small business loan — check if the monthly payment fits inside your projected cash flow.
• Decide between cash vs financing — compare the total cost of borrowing against paying upfront.

• Boost your credit score before applying. Even a 40-point jump can drop your rate by 1%+.
• Get quotes from at least 3 lenders. Banks, credit unions, and online lenders often differ by full percentage points.
• Choose the shortest term you can afford. Total interest drops sharply with shorter terms.
• Avoid prepayment penalties. Confirm you can pay extra without fees before signing.
• Round payments up. Rounding $312 to $350/month is a near-painless way to slash interest.