Loan Balance Calculator
Enter your original loan amount, annual interest rate, loan term, and how many payments you have made. The calculator shows the exact outstanding principal remaining, the monthly payment, how much interest you have paid so far, and how much principal you have paid off. Scroll down for a full month-by-month amortisation schedule and a balance-over-time chart.
What is a loan balance calculator?
A loan balance calculator tells you exactly how much principal you still owe on an amortising loan (mortgage, car loan, personal loan, student loan) after a specific number of payments. It also shows your monthly payment, how much of that payment has gone to principal vs. interest, and how long you have left until the loan is fully paid. This matters when you are thinking about refinancing, selling an asset, making an early payoff, or simply want to track your progress.
The remaining balance formula
For a standard amortising loan the remaining balance after k payments is: B(k) = L x (1+r)^k minus PMT x ((1+r)^k minus 1) / r, where L is the original loan amount, r is the monthly interest rate (annual rate divided by 12), and PMT is the fixed monthly payment. The monthly payment itself is: PMT = L x r / (1 minus (1+r)^-n), where n is the total number of months. Early payments are mostly interest; only later do they chip away at the principal in meaningful amounts, which is why the balance falls slowly at the start and then rapidly near the end.
How extra payments reduce your balance
Because interest is charged on the outstanding principal, every dollar you pay above the minimum goes directly to reducing the principal. That lower principal generates less interest next month, meaning more of your regular payment also goes to principal, compounding the effect. The extra payment field lets you model this: even a small additional amount each month can knock years off your term and save thousands in interest. Run the calculator with and without your planned extra amount to see the difference on the chart.
When to use this calculator
Use it before refinancing to know your exact payoff amount (add one or two months of buffer for interest accruing after your quote date). Use it when selling a financed asset to check whether the sale price covers the outstanding balance. Use it to decide whether making extra payments now is better than investing the same money, by comparing the guaranteed interest-rate saving against expected investment returns. And use it simply to stay motivated: watching the balance and the percentage-paid gauge move in real time is one of the most effective ways to stay on track.
How loan term affects total interest cost
| Term | Monthly payment | Total interest | Total cost |
|---|---|---|---|
| 2 years | $1,118 | $839 | $25,839 |
| 3 years | $767 | $1,259 | $26,259 |
| 5 years | $489 | $2,340 | $27,340 |
| 7 years | $374 | $3,339 | $28,339 |
| 10 years | $284 | $9,066 | $34,066 |
| 15 years (mortgage) | $218 | $14,240 | $39,240 |
| 30 years (mortgage) | $158 | $31,781 | $56,781 |
Example: $25,000 loan at 6.5% APR. Longer terms lower the monthly payment but dramatically increase total interest paid.
Frequently asked questions
What is the remaining balance on a loan?
It is the outstanding principal you still owe to the lender, not counting any future interest that has not yet accrued. Each monthly payment covers the interest for that month first; whatever is left over reduces the remaining balance. Because early payments are mostly interest, the balance falls slowly at first and accelerates toward the end of the term.
How do I calculate my remaining loan balance?
Use the formula B(k) = L x (1+r)^k - PMT x ((1+r)^k - 1) / r, where L is the original loan, r is the monthly interest rate (annual rate / 12), PMT is the fixed monthly payment, and k is how many payments you have made. This calculator does all of that automatically and also produces a full amortisation schedule.
Why does my balance not seem to go down much in the early years?
This is the normal effect of amortisation. In the early months, interest on the large outstanding balance consumes most of each payment, leaving only a small portion to reduce the principal. As the principal shrinks, each payment covers less interest and more principal, so the balance starts falling faster. The amortisation schedule below the calculator shows this month by month.
Does paying extra each month really make a big difference?
Yes. Because interest is charged on the outstanding balance, any extra principal payment reduces future interest immediately. On a long mortgage even an extra $100 per month can shave years off the term and save tens of thousands in interest. Use the extra monthly payment field and the chart to see the exact effect for your numbers.
Can I use this for a mortgage?
Yes. Enter your original mortgage amount, the interest rate, the term in years, and how many monthly payments you have made. The result is the current payoff balance (which your lender will quote slightly differently because they add accrued interest to the statement date). Use the schedule to see when your principal finally overtakes interest in each payment.
What is the difference between the loan balance and the payoff amount?
The balance is the principal owed as of your last payment. The payoff amount is what you would need to pay today to close the loan, and it includes interest that has accrued since the last payment date. If you are requesting an official payoff quote from your lender, add 15-30 days of daily interest to the balance shown here (daily interest = balance x annual rate / 365).