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Calcenta

Loan Calculator

Calculate the monthly payment, total interest, and payoff date on any fixed-rate loan - then see the full schedule behind the number.

Loan Calculator

Applied entirely to principal

Monthly payment

$525.05

$25,000 over 5 years at 9.50% APR

Total interest

$6,503

Total repaid

$31,503

Payoff in

5 years

Paid off

September 2031

Your first payment

  • Goes to principal$327.13
  • Goes to interest$197.92

Interest is charged on the balance, which is highest at the start. That split reverses as the loan runs.

Principal vs interest, year by year

The point where the bars flip is when most of your payment finally starts reducing the balance.

How the loan calculation works

Almost every fixed-rate loan you will ever take — personal, auto, student, home improvement — works the same way underneath. You borrow a sum, you repay it in equal monthly installments, and each installment is split between interest owed for that month and principal that reduces the balance. That structure is called amortization, and it is what this calculator models.

The payment comes from a single formula:

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

P is the amount borrowed, r is the monthly rate (annual rate ÷ 12), and n is the total number of payments. The formula solves for the fixed payment that reduces the balance to exactly zero on the final month.

Take a $25,000 personal loan at 9.5% APR over 5 years. That is r = 0.0079167 and n = 60, giving a monthly payment of $525.13. Over the full term you repay $31,508 — so $6,508 of interest on a $25,000 loan.

What surprises most borrowers is how that payment is divided early on. In month one, interest is $25,000 × 0.0079167 = $197.92, so only $327.21 of your $525.13 touches the balance. By the final month almost the entire payment is principal. This front-loading is why paying extra early is so much more effective than paying extra late.

Three things worth checking before you sign:

  • Compare APR, not the monthly payment. A lower payment usually means a longer term, which almost always means more total interest. The APR includes most fees, so it is the honest comparison number.
  • Ask about prepayment penalties. Extra payments only help if the lender applies them to principal without charging you. Most US personal loans have no penalty, but it is worth confirming.
  • Watch origination fees. A 5% origination fee on a $25,000 loan is $1,250 that you either pay up front or borrow — either way it raises your effective cost above the stated rate.

Enter your own figures above to see the payment, the total interest, and the month-by-month schedule.

Disclaimer: This calculator provides estimates for informational purposes only and is not financial advice. Your actual rate, taxes, fees, and payment will vary - confirm figures with a licensed lender or financial professional.

Frequently asked questions

What is the difference between interest rate and APR?

The interest rate is the cost of borrowing the principal. The APR also folds in most lender fees, such as origination charges, expressed as a yearly rate. Because APR captures more of the true cost, it is the right number to use when comparing two loan offers.

Why does so little of my early payment go to principal?

Interest is charged on the outstanding balance, which is at its highest at the start. On a $25,000 loan at 9.5%, the first month accrues about $198 in interest, so only the remainder of your payment reduces the balance. As the balance falls, the interest portion shrinks and the principal portion grows.

Does making extra payments actually help?

Yes, and more than most people expect. Extra money applied to principal permanently removes the interest that balance would have generated for the rest of the term. Paying extra in the first few years has a much larger effect than the same amount paid near the end.

What loan term should I choose?

A longer term lowers the monthly payment but raises total interest, sometimes dramatically. Pick the shortest term whose payment fits comfortably in your budget, leaving room for emergencies so you are not forced to refinance later.

Can I use this for a student or business loan?

Yes, for any fixed-rate loan with equal monthly payments. It is not suitable for loans with variable rates, interest-only periods, balloon payments, or income-driven repayment plans, since those do not amortize on a fixed schedule.

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