Comprehensive loan amortization schedule with flexible payment options
Understand your loan with a comprehensive amortization schedule
A loan amortization schedule shows how every payment you make is split between principal and interest over time. With this comprehensive loan amortization calculator you can model loans used around the world, including monthly, bi-weekly, weekly, quarterly and yearly repayment plans, and instantly see how long it will take to pay off your debt.
How loan amortization works
When you take a fully amortizing loan, your goal is to reduce the balance to zero by the end of the term. Each payment covers interest on the outstanding balance plus a portion of the principal. The core idea is that the balance shrinks over time, so interest becomes smaller and the principal portion grows.
The calculator uses the standard annuity formula for fixed payments. Let \( P \) be the initial principal, \( i_{\text{annual}} \) the nominal annual interest rate, and \( m \) the number of payments per year. The periodic rate is \[ r = \frac{i_{\text{annual}}}{m}. \] For a total of \( n \) payments, the regular payment amount \( A \) is \[ A = P \cdot \frac{r}{1 - (1 + r)^{-n}}. \]
Flexibility for different countries and products
Different countries and lenders offer a wide range of repayment conventions. Some markets favour monthly payments, others use weekly or bi-weekly cycles, and many products allow long or short terms. This calculator lets you choose the number of payments per year and the length of the term in years or in months, so that the schedule can reflect loans used in many regions and currencies.
You can also set the currency symbol used in all results. Whether you are working in dollars, euros, pounds, yen or any other currency, the schedule and summary figures will match your selected symbol while keeping the same mathematical logic.
Using extra payments to shorten your loan
Making extra payments is one of the most effective ways to reduce total interest and shorten your payoff time. In this calculator you can add a constant extra amount to every period. Internally the tool keeps the standard payment \( A \) and then adds your extra payment to compute the total cash outflow per period.
Each simulated period calculates: \[ \text{Interest} = B_{\text{start}} \cdot r, \] where \( B_{\text{start}} \) is the balance at the beginning of the period. The principal portion is then \[ \text{Principal} = \text{TotalPayment} - \text{Interest}, \] and the new balance is \[ B_{\text{end}} = B_{\text{start}} - \text{Principal}. \] The final payment is automatically adjusted so that \( B_{\text{end}} \) reaches exactly \( 0 \) without becoming negative.
Reading the summary cards and detailed table
At the top of the results you will see summary cards showing the combined scheduled and extra payment per period, the total amount paid over the life of the loan, the total interest cost, the number of payments and the estimated payoff date. These high level metrics are useful for quick comparisons between scenarios.
Below the cards, the amortization table lists each payment with the following details:
- Payment number – the sequence index for each instalment.
- Payment date – estimated based on the start date and payment frequency.
- Beginning balance – outstanding principal at the start of the period.
- Scheduled payment and extra payment – the regular payment plus your additional amount.
- Principal and interest – how the total payment is split.
- Ending balance – principal remaining after the payment is applied.
- Cumulative principal and interest – running totals so you can see how much you have paid so far.
You can export the table to CSV or Excel for further analysis, budgeting or reporting, and the customize columns feature lets you choose exactly which fields to display and in what order.
Practical ways to use this calculator
This comprehensive amortization tool can support many real world decisions:
- Comparing loan offers – test different terms and interest rates to understand the long term cost.
- Planning early payoff – model different extra payment levels and see how the payoff date changes.
- Budgeting monthly cash flow – check how payment frequency affects your regular obligations.
- Understanding interest cost – evaluate how much of your payment is interest at each stage of the loan.
Because all calculations are performed dynamically, you can freely adjust the inputs and instantly see the impact on the results, making this calculator a practical companion for personal, business or advisory use.