📅 Amortization Schedule Calculator

Use this amortization schedule calculator to break down each loan payment into principal and interest. Enter your loan amount, interest rate, term, and optional extra payments to see your regular payment, total interest, and how quickly you could pay off your debt.

Amortization results

Enter your loan details above and select Calculate Amortization Schedule to see your regular payment, total interest, and a detailed schedule of how the balance declines over time.

Amortization schedule by payment period

Once you calculate your amortization schedule, this section will show a period-by-period breakdown of each payment, including interest, principal, and remaining balance.

Amortization calculator inputs and key terms

These inputs describe your loan and how payments are structured. Knowing what each term means can make it easier to compare loans and understand your repayment plan.

• Loan amount (principal): The original amount you borrow, before interest and fees. This is the balance the amortization schedule will pay down over time.
• Annual interest rate (%): The yearly rate your lender charges on the outstanding balance, expressed as a percentage (for example, 6.5% per year).
• Loan term (years): How long you have to repay the loan if you make only the required payments. Shorter terms usually mean higher payments but less total interest.
• Payment frequency: How often you make payments (monthly, every two weeks, or weekly). Changing the frequency can slightly change the effective interest paid over time.
• Optional extra payment per period: Any additional amount you plan to pay on top of the required payment each period. Extra payments typically go straight to principal, which can reduce total interest and shorten the payoff time.
• Regular payment per period: The calculated payment that, if made consistently at the chosen frequency, will pay off the loan in exactly the chosen term (assuming a fixed interest rate).
• Total interest paid: The sum of all interest charges over the life of the loan under the schedule shown. Comparing standard vs. extra-payment totals highlights potential savings.
• Number of payments: The total count of scheduled payments until the balance is reduced to zero in the standard and extra-payment scenarios.
• Amortization schedule: A period-by-period listing of each payment, showing how much goes toward interest and how much goes toward principal, along with the remaining balance after each payment.

Formulas used in the Amortization Schedule Calculator

This calculator uses the standard fixed-rate loan payment formula to find the periodic payment and then builds an amortization schedule by applying interest and principal step by step.

Periodic interest rate and number of payments

Let:
P = loan amount (principal)
r = annual interest rate (decimal, for example 0.065 for 6.5%)
m = number of payments per year (12 monthly, 26 biweekly, 52 weekly)
n = total number of payments = m × years
i = periodic rate = r ÷ m

Fixed payment formula (no extra payments)

When the interest rate is greater than zero, the standard fixed payment per period PMT is:
PMT = P × i ÷ (1 − (1 + i)−n)
If the annual interest rate is 0%, the formula simplifies to:
PMT = P ÷ n

Amortization step for each payment

For each payment period, starting from the current balance B:
Interest = B × i
Principal = Payment − Interest
New balance = B − Principal
The calculator repeats this step-by-step process until the balance reaches zero, building the schedule you see in the table.

Extra payments and accelerated payoff

When you enter an extra payment, the calculator adds it to the required payment and applies the combined amount to each period. The extra portion goes directly to principal, which can reduce the number of payments and the total interest paid:
Payment with extra = PMT + Extra
The schedule is recalculated using this higher payment until the balance is reduced to zero, allowing the tool to estimate interest savings and time saved.

Lenders may have their own rules about how and when extra payments are applied, as well as any prepayment penalties. Always review your loan agreement to confirm how extra payments will be handled.

Amortization Schedule Calculator FAQs

• What is an amortization schedule, and why is it useful?
  An amortization schedule is a detailed table showing every payment on a loan, including how much of each payment goes to interest and how much goes to principal. It helps you see how quickly your balance falls, how much interest you pay over time, and the impact of extra payments. Many borrowers use it to compare loan options and plan payoff strategies.
• Why does the interest portion of my payment shrink over time?
  Interest is calculated on the remaining balance. Early in the loan, the balance is high, so the interest portion is larger. As you pay down principal, the balance shrinks, so interest charges decline and more of each payment goes toward principal instead. This shifting mix is a normal feature of amortized loans.
• How do extra payments reduce my total interest?
  Extra payments typically go straight to principal, which immediately lowers the balance used to calculate future interest charges. Over time, this can significantly reduce total interest and shorten the payoff period. Even small, regular extra payments can add up to large savings on long-term loans like mortgages.
• Should I choose monthly, biweekly, or weekly payments?
  Monthly payments are the most common, but some borrowers prefer biweekly or weekly schedules to line up with their paychecks or to increase payment frequency. Biweekly schedules often result in the equivalent of one extra monthly payment per year, which can help pay off the loan faster. Always confirm how your lender handles different payment frequencies.
• Why do my lender’s numbers differ from this calculator?
  Lenders may use slightly different compounding conventions, rounding rules, fees, escrow amounts, or payment schedules. This calculator focuses on the core principal and interest payments under fixed-rate assumptions. Use it as a planning tool, but rely on official disclosures from your lender for exact payment amounts and totals.
• Can I use this calculator for any type of loan?
  This tool works best for fixed-rate, fully amortizing loans such as traditional mortgages, auto loans, and many personal loans. It does not model adjustable-rate mortgages, interest-only periods, balloon payments, or complex fee structures. For those products, ask your lender for a customized schedule.