Amortization Schedule Calculator

This amortization calculator lets you estimate your monthly loan or mortgage repayments in seconds. Enter your loan amount, interest rate, term and start date, click "Calculate", and you'll get your fixed monthly payment together with a complete amortization schedule — showing exactly how much of every payment goes toward the principal and how much is eaten by interest.

Amortization is what turns the lump sum you borrowed into a series of equal payments. Each one covers the interest accrued since the last payment, and whatever is left reduces the balance. Because interest is charged on what you still owe, the early payments are mostly interest — the single most useful thing a schedule will tell you.

Use it for a student loan, a personal loan or any other fixed-rate loan. For a house, the mortgage amortization calculator adds property taxes, insurance, HOA fees and PMI to the payment; for a vehicle, the auto loan amortization calculator handles the trade-in and sales tax. The chart under the results tracks your balance month by month and marks the crossover point where principal finally outweighs interest.

New to the term? Start with what amortization is and how it works. Prefer working in a spreadsheet? Download our free amortization schedule Excel template — the same math in a worksheet you can save, print and adapt to your own scenarios.

FAQ

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What is amortization?

Amortization is the process of paying off a loan with regular fixed payments over time. Each payment covers the interest accrued since the previous payment and reduces the outstanding balance by the remainder. As the balance shrinks, the interest portion of every payment gets smaller and the principal portion grows, until the loan is fully repaid at the end of the term.

What is an amortization schedule?

An amortization schedule is a table listing every payment over the life of a loan, splitting each one into interest and principal and showing the remaining balance afterwards. Lenders use it to set your fixed payment; borrowers use it to see the real cost of a loan, to compare offers, and to plan extra payments where they have the most impact.

What is an amortization table?

An amortization table is the same thing as an amortization schedule — the two terms are used interchangeably. It's the row-by-row breakdown of every payment showing interest, principal and remaining balance. This calculator produces one automatically, grouped by year so you can collapse the detail or expand any single year.

How is my monthly payment calculated?

Your payment depends on three numbers: the amount borrowed, the interest rate and the number of payments. The standard formula is M = P × (r(1+r)ⁿ) / ((1+r)ⁿ − 1), where P is the principal, r is the periodic interest rate and n is the number of payments. This calculator applies it instantly and shows the result along with the full payment breakdown.

How do I build an amortization schedule by hand?

Work one row at a time. Multiply the current balance by the periodic rate to get that month's interest, subtract the interest from the fixed payment to get the principal, then subtract the principal from the balance to get the new balance. Repeat with the new balance. The arithmetic is simple, but a 30-year mortgage takes 360 rows — which is why a calculator or spreadsheet is worth using.

Why is so much of my early payment interest?

Because interest is charged on what you currently owe, and at the start you owe the entire amount. On a $250,000 loan at 6.50%, the first month's interest alone is $1,354.17 out of a $1,580.17 payment. The proportion improves every month, but on a 30-year term it takes over nineteen years before more of your payment goes to principal than to interest.

Can I pay my loan off faster?

Yes — any amount you pay on top of the required payment goes straight to the principal, which shrinks the base on which future interest is charged. On a $250,000 loan at 6.50%, an extra $100 a month cuts nearly five years off the term and saves close to $59,000 in interest. Check your loan agreement for prepayment penalties before committing.

Do biweekly payments really pay off a loan faster?

Yes, but not for the reason most people assume. Paying half your monthly payment every two weeks produces 26 half-payments a year, which is 13 full payments rather than 12. The saving comes from that one extra payment, not from the payment frequency itself — you would get almost the same result by adding one-twelfth of a payment to each month.

What is negative amortization?

Negative amortization occurs when your payment is smaller than the interest owed for that period. The unpaid interest is added to the balance, so the debt grows despite the payments. It appears in some adjustable-rate mortgages with payment caps, in graduated-payment plans and in income-driven student loan repayment. It is the one case where a payment schedule works against you.

Does my amortization schedule change if the interest rate changes?

On a fixed-rate loan, no — the rate and the payment are locked for the whole term. On an adjustable-rate loan the schedule is recalculated at every reset using the new rate and the remaining balance and term, which produces a new fixed payment until the next adjustment. Any schedule you build for an ARM is an estimate valid only until that reset.

Can I get a schedule for a loan I'm already paying?

Yes. Enter your current outstanding balance rather than the original loan amount, your current rate, and the number of payments you have left rather than the original term. The schedule you get will run from today to payoff. It won't show the payments you've already made, but the remaining interest and payoff date will be accurate.

What is the difference between amortization and depreciation?

Both spread a cost over time, but they apply to different things. Amortization covers intangible assets such as patents, trademarks and purchased software, and is almost always straight-line. Depreciation covers physical assets such as vehicles, machinery and buildings, and can use accelerated methods. In lending, "amortization" instead means the repayment of a loan through scheduled payments.

Definitions

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Loan Amount

The amount you're actually borrowing, also called the principal. For a mortgage that's the purchase price minus your down payment, not the price of the home; for an auto loan it's the vehicle price minus your down payment and trade-in, plus any tax and fees rolled into the financing. Enter the financed figure rather than the sticker price, or the schedule will overstate every payment.

Interest Rate

The annual interest rate on the loan, entered as a percentage. Where a lender quotes an APR, that figure includes certain fees as well as interest, so it will be slightly higher than the rate used to compute your payment — use the note rate here for an exact schedule, or the APR if you want a more conservative estimate. Rates vary widely by loan type and credit score, so it's worth running two or three scenarios.

Loan Term

How long you have to repay, in years, months or weeks. A longer term lowers the monthly payment but raises the total interest, sometimes dramatically: stretching a mortgage from 15 to 30 years roughly halves the payment while more than doubling the interest. Compare terms in the schedule rather than on the payment alone — the difference in lifetime cost is where the real decision lies.

Start Date

The month the loan closes and the schedule begins. This doesn't affect your payment or the total interest at all; it sets the calendar dates in the schedule, so you can see which month the crossover falls in, when the balance drops below a threshold, and the exact date of your final payment. If you don't know the closing date yet, leave it at today and re-run the calculation later.

How amortization works

On an amortizing loan the payment is fixed, but what that payment does changes every single month. The lender charges interest on the balance you still owe, so the interest share is at its largest on day one and shrinks as the balance comes down. The principal share grows by exactly the same amount, which keeps the total payment level.

Take a $250,000 loan at 6.50% over 30 years. The payment is $1,580.17 a month. Of the very first one, $1,354.17 is interest and only $226.00 touches the debt. Across the whole first year you hand over $18,962 and reduce the balance by $2,794 — under 15% of what you paid.

The two halves don't cross over until payment 233, more than nineteen years in. By the final payment you'll have paid $568,861 for the $250,000 you borrowed, of which $318,861 is interest.

The amortization formula

The fixed payment comes from one equation:

M = P × (r(1+r)ⁿ) / ((1+r)ⁿ − 1)

where P is the principal, r is the interest rate per period (the annual rate divided by 12 for a monthly loan) and n is the total number of payments.

For the loan above: P = 250,000, r = 0.065 / 12 = 0.00541667, n = 30 × 12 = 360. That gives (1+r)ⁿ = 6.991798, so M = 250,000 × 0.00541667 × 6.991798 / 5.991798 = $1,580.17.

The schedule itself is then just three steps repeated once per payment:

  1. Interest = current balance × r
  2. Principal = M − interest
  3. New balance = current balance − principal

Repeat until the balance reaches zero. That is all an amortization calculator does — the work is in doing it 360 times without an arithmetic slip.

How to read your amortization schedule

Every row is one payment, split into what the lender keeps and what actually reduces your debt:

Payment Date Interest Principal Balance
1 Jan 2026 $1,354.17 $226.00 $249,774.00
2 Feb 2026 $1,352.94 $227.23 $249,546.77
3 Mar 2026 $1,351.71 $228.46 $249,318.31
233 May 2045 $788.75 $791.42 $144,824.47
360 Dec 2055 $8.51 $1,571.66 $0.00

Three things are worth noticing. The payment never changes. The interest column falls slowly at first and then faster, because it tracks a balance that is itself falling faster and faster. And at payment 233 — the crossover — principal finally overtakes interest, yet you still owe $144,824, well over half the original loan, despite being nearly two-thirds of the way through the term.

That asymmetry is why selling or refinancing early costs more than people expect: the equity you have built is much smaller than the fraction of payments you have made.

What extra payments really save

Anything you pay above the required amount goes straight to principal, which permanently shrinks the base that all future interest is charged on. The effect compounds, so it is far larger than the extra money itself.

On the same $250,000 loan at 6.50%:

  • $100 extra a month clears the loan in 304 payments instead of 360 — four years and eight months early — and saves $58,860 in interest.
  • $200 extra a month clears it in 265 payments, nearly eight years early, saving $97,618.

The mortgage payoff calculator does this arithmetic on your own balance: enter what is left, the rate and the term still to run, and it returns the new payoff date and the interest that never gets charged.

Two practical cautions. Check your loan agreement for prepayment penalties first — they are rare on mortgages but common on some auto and personal loans. And tell the servicer in writing that extra money is to be applied to principal, not held as a prepaid future installment, which is the default at some lenders.

Loans that don't amortize the way you expect

Not every loan follows a clean amortization schedule:

  • Interest-only loans charge only the interest for an initial period, so the balance doesn't move at all until the full payment kicks in.
  • Balloon loans are amortized over a longer schedule than their actual term, leaving a large lump sum due at the end.
  • Negative amortization happens when the payment is smaller than the interest due; the shortfall is added to the balance and your debt grows even though you are paying.
  • Adjustable-rate loans re-cut the schedule at every rate reset, so any schedule you build is only valid until the next adjustment.
  • Credit cards have no fixed end date at all — the minimum payment is a percentage of the balance, so it falls as the balance falls and the payoff stretches out.

This loan amortization calculator should only be used to estimate your repayments since it doesn't include taxes or insurance.