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Finance & business

Loan calculator and monthly payments

Calculate loan payments, interest, total cost, payoff date and remaining balance. Explore the amortization schedule, charts and the impact of extra repayments.

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  • 100% local
  • Instant
  • Free
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  • Works offline
Monthly payment
—/ mois
— payments
Loan ends —
Principal borrowed
—
Total interest
—
Total amount repaid
—
Actual term
—

Loan cost breakdown

—Total remboursé
Principal—
—
Interest—
—

Loan balance over time

Capital restant dû, capital remboursé, intérêts cumulés et total remboursé.

Remaining principalPrincipal repaidCumulative interestTotal remboursé

Principal and interest repaid by year

Visualisez la part de capital et d’intérêts payée chaque année.

Capital rembourséIntérêts payésCapital restant dû

Impact of extra repayments

Compare the original loan with your accelerated repayment scenario.

Add an extra repayment to see the potential savings.

Amortization schedule

Visualisez le détail de chaque échéance calculée par le LoanEngine.

Why use this tool?

This loan calculator provides a detailed simulation of a loan: monthly payment, total cost, interest, payoff date, remaining balance, repayment progress and a complete amortization schedule. Change the amount borrowed, annual interest rate or term to see the effect on your budget immediately. Advanced options also let you measure the effect of monthly or one-off extra repayments.

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Your data stays on your device and is never sent to our servers.

Smart processing

Calculate and compare financial scenarios with clear indicators and explicit formulas.

Supported formats

Amounts, rates, terms and financial assumptions depending on the calculator.

Save time

Get a clean, ready-to-use result in seconds without installing software or configuring a complex workflow.

Loan payment formula

For a fixed-rate amortizing loan with constant payments, the theoretical monthly payment can be calculated from the principal, periodic interest rate and number of payments.

Monthly payment

M = C × i × (1 + i)ⁿ / ((1 + i)ⁿ − 1)

This formula determines the constant payment, excluding fees and insurance, for a fixed-rate amortizing loan.

Interest for a payment

Iₖ = CRDₖ₋₁ × i

Interest for payment k is calculated on the remaining principal before that payment.

Principal repaid

Aₖ = M − Iₖ

The principal repaid equals the payment minus the period's interest.

New remaining principal

CRDₖ = CRDₖ₋₁ − Aₖ

After each payment, the remaining principal falls by the amount of principal actually repaid.

M
theoretical payment excluding insurance and fees
C
initial principal borrowed
i
periodic interest rate, here the monthly rate
n
total number of payments
Iₖ
interest paid at payment k
CRD
remaining principal

Example: for €200,000 borrowed over 20 years at a 3.5% nominal annual rate, the calculation uses 240 monthly payments and a monthly rate equal to the annual rate divided by 12.

See the detailed explanation

Understand the amortization schedule

Each payment is split between interest and principal repayment. As the loan progresses, the interest share decreases while the principal share increases.

  • Track the remaining balance
  • Separate principal from interest
  • Read each payment month by month
Understand the amortization schedule

Impact of extra repayments

An extra repayment directly reduces the outstanding principal. Future interest is then calculated on a smaller balance, which can reduce both the cost and the term of the loan.

  • Reduce principal faster
  • Save interest
  • Potentially shorten the loan term
Understand their impact

Fonctionnement

How does this tool work?

The calculator uses a shared financial engine, LoanEngine, which centralizes all loan calculation rules. For an amortizing loan with fixed monthly payments, the engine converts the nominal annual interest rate into a monthly rate, then calculates the theoretical payment from the principal and number of payments. At each payment, interest is calculated on the outstanding balance before repayment. The difference between the payment and interest is the principal repaid. The remaining balance therefore falls month by month, progressively reducing the interest charged.

The amortization schedule is not rebuilt separately in the interface: it comes directly from the same LoanEngine. Each row contains the payment, principal portion, interest portion, any extra repayments, cumulative amounts and remaining balance. The charts use the same data. This architecture ensures that a correction to the engine is automatically reflected in the summary, curves, annual charts and schedule.

When an extra repayment is added, the engine applies it directly to principal after the normal payment. The balance falls faster and future interest is recalculated on the new remaining balance. The base contractual payment remains displayed, but the loan may finish earlier. The comparison panel then measures interest savings and the number of payments saved versus the original scenario without extra repayments.

Use cases

Plan a financing project

Quickly estimate the monthly payment for an amount, rate and term before requesting offers from a bank or lender.

Compare different loan terms

See how a shorter term raises the monthly payment but generally reduces total interest, while a longer term lowers the payment but increases total cost.

Understand an amortization schedule

See month by month the principal, interest, cumulative amounts and remaining balance to understand how the loan changes over time.

Test an early repayment

Simulate a monthly or one-off extra payment and measure potential interest savings and the reduction in loan term.

Check a loan offer

Compare figures shown in a commercial simulation with a payment calculated from principal, nominal rate and term.

Guide

How to use this tool

  1. 1

    Enter the amount, rate and term

    Enter the principal borrowed, nominal annual interest rate and term in years or months. The simulation recalculates automatically.

  2. 2

    Review the payment and total cost

    Immediately see the estimated monthly payment, total interest, total repaid, number of payments and payoff date.

  3. 3

    Explore the charts

    The donut compares principal and interest, the line chart tracks remaining balance and cumulative amounts, and the annual chart shows repayments over time.

  4. 4

    Review the amortization schedule

    Switch between monthly and yearly views to inspect each payment or get an annual summary.

  5. 5

    Test extra repayments

    Add a monthly amount or one-off payment to see how much interest and time could be saved.

Examples

€200,000 loan over 20 years

The monthly payment is calculated over 240 payments. Early payments contain proportionally more interest than later ones.

Input

€200,000 · 3.5% · 20 years

Shorter term

A shorter term increases the monthly payment but reduces the time over which interest accrues, generally lowering the total cost of the loan.

Input

€200,000 · 3.5% · 15 years

Extra repayment

The extra amount directly reduces the remaining principal. Future interest falls and the loan may be paid off months or years earlier.

Input

+€100 per month

Tips and best practices

  • Always compare several terms: a lower monthly payment does not necessarily mean a cheaper loan, because extending the term often increases total interest.
  • The rate used here is the nominal annual interest rate. Do not confuse it with APR, which can include other mandatory borrowing costs.
  • Early repayment may be subject to conditions or charges under your contract. This simulation measures the mathematical effect on the loan, not possible contractual fees.
  • When comparing two offers, do not look only at the monthly payment: also consider total repaid, interest, term and external fees not included in this initial simulation.
  • The remaining balance is especially useful for estimating the loan position at a given date, for example before a sale, refinancing or early repayment.

Frequently asked questions

How is a loan payment calculated?

For a fixed-rate amortizing loan, the payment depends on the principal borrowed, periodic interest rate and total number of payments. The financial formula produces a constant payment while the interest share gradually falls and the principal share rises.

Why do you pay more interest at the start of a loan?

Interest for each period is calculated on the remaining balance. At the start, that balance is close to the original loan amount, so interest is higher. As principal is repaid, the calculation base falls and so does the interest share.

What is the remaining loan balance?

It is the portion of the principal borrowed that has not yet been repaid. It should not be confused with all future payments, which also include future interest.

What is an amortization schedule for?

An amortization schedule details the loan payment by payment. It shows the payment date, amount paid, principal, interest, cumulative amounts and remaining balance after each payment.

What is the difference between the nominal rate and APR?

The nominal rate is mainly used to calculate loan interest. APR is designed to represent the overall cost of borrowing by including various mandatory fees and costs under applicable rules. This calculator uses the nominal rate and therefore does not display an incomplete or misleading APR.

Does an extra repayment always shorten the loan term?

In this simulation, extra repayments are applied directly to principal while the base contractual payment is maintained. Principal therefore falls faster, reducing future interest and generally shortening the term. Actual terms depend on the loan contract.

Is loan insurance included?

No. This version simulates the financial mechanics of the loan using principal, nominal rate and term. Insurance, arrangement fees, guarantees and other costs are not included and can be handled separately in future specialized calculators.

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