Loan Calculator - Monthly Payment, Interest and Total Cost

How the monthly payment works

A typical fixed-rate loan is repaid with a constant scheduled monthly payment. Each payment is split into two parts:

• Interest is the cost of borrowing, calculated on the remaining balance.
• Principal is the part that reduces your outstanding balance.

Early on, a larger share of each payment goes to interest. As the balance falls, the interest portion shrinks and more of each payment goes to principal. This pay-down process is called amortization.

Formula used by this calculator

For a loan with amount P, annual interest rate R and a term of n months, the monthly rate is:

r = R / 12

The scheduled monthly payment is then:

Payment = P × r × (1 + r)n / ((1 + r)n − 1)

When the interest rate is 0%, the monthly payment is simply P ÷ n.

Worked example

A €10,000 loan at 5% annual interest over 36 months gives a monthly rate of r = 0.05 / 12 = 0.004167. Applying the formula:

• Scheduled monthly payment: €299.71
• Total paid over 36 months: €10,789.56
• Total interest cost: €789.56

In month 1, roughly €41.67 of the €299.71 payment is interest and €258.04 reduces the balance. By month 36, almost the entire payment goes to the remaining principal.

How the term length affects cost

Stretching the same €10,000 loan at 5% from 36 to 60 months lowers the monthly payment from €299.71 to €188.71, a saving of €111 per month. However, total interest rises from €789.56 to €1,322.60 — an extra €533 paid for the longer horizon. Choosing a term is a trade-off between monthly affordability and total borrowing cost.

Financed and recurring fees

Many lenders charge an origination fee or other upfront costs. In this calculator those fees are treated as financed fees: they are added to the starting balance and repaid with interest. A 2% origination fee on a €10,000 loan adds €200 to the financed balance, raising the monthly payment to approximately €305.70 and the total cost to €11,005.20. You can also model fees as one-time, yearly or monthly amounts.

• Financed fees increase your monthly payment and total interest cost.
• Recurring fees increase total cost; monthly fees also increase your monthly outlay.
• If your fees are paid out of pocket and not financed, set the fee fields to 0.

What the total cost shows

The total cost of the loan is the sum of all payments made from start to payoff: principal, interest, financed origination fees and any recurring fees you added. It is the single number that lets you compare two loans on a like-for-like basis, regardless of differences in rate, term or fee structure.

Borrowing basics

When you take out a loan you trade future payments for money today. The loan amount is the cash you receive, the interest rate is the price of that money and the term is how long you repay it. Longer terms reduce the monthly payment but usually increase the total cost, while a higher rate raises both.

To compare offers effectively, look beyond the headline rate. This calculator surfaces the scheduled monthly payment, total interest, total fees financed and total cost of the loan so you can judge each offer on a like-for-like basis.

How to use this calculator

• Budget check: enter your expected loan amount and rate to confirm the monthly payment fits your cash flow before you borrow.
• Term comparison: run 36 months and 60 months side by side to see the monthly saving versus the extra interest cost.
• Fee impact: add an origination fee or monthly service charge to see how it changes the total cost over the full term.
• Offer comparison: model each competing loan offer and compare total costs rather than monthly payments alone.

Supporting calculators

• Return vs borrowing cost: use the ROI Calculator to check whether an expected project or investment return is strong enough relative to your loan cost.
• Payoff timeline by life stage: use the Age Calculator to place your final payoff date against retirement or other age milestones.
• Income coverage planning: use the Investment Income Calculator to estimate how much capital is needed to cover a fixed monthly obligation such as a loan payment.