Finance
Amortization Calculator
Enter a loan amount, interest rate, and term to see the monthly payment, the total interest, and a complete payment-by-payment schedule — principal, interest, and remaining balance for every period. Add an extra payment to watch the payoff date move up. Results update live.
Loan details
$
%
years
Optional — applied straight to principal.
$
Monthly payment
$1,896.20
Total interest
$382,633
Total paid
$682,633
Principal
$300,000
Payments
360
PrincipalInterest
Updates as you type
Try an example
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Amortization schedule
Every payment split into principal and interest, with the balance falling to zero. Toggle between a yearly summary and the month-by-month detail.
30 years
| Year | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $22,754.45 | $3,353.18 | $19,401.27 | $296,646.82 |
| 2 | $22,754.45 | $3,577.74 | $19,176.70 | $293,069.08 |
| 3 | $22,754.45 | $3,817.35 | $18,937.10 | $289,251.73 |
| 4 | $22,754.45 | $4,073.01 | $18,681.44 | $285,178.72 |
| 5 | $22,754.45 | $4,345.79 | $18,408.66 | $280,832.93 |
| 6 | $22,754.45 | $4,636.83 | $18,117.62 | $276,196.10 |
| 7 | $22,754.45 | $4,947.37 | $17,807.08 | $271,248.73 |
| 8 | $22,754.45 | $5,278.70 | $17,475.75 | $265,970.03 |
| 9 | $22,754.45 | $5,632.23 | $17,122.22 | $260,337.81 |
| 10 | $22,754.45 | $6,009.43 | $16,745.02 | $254,328.38 |
| 11 | $22,754.45 | $6,411.89 | $16,342.56 | $247,916.49 |
| 12 | $22,754.45 | $6,841.31 | $15,913.14 | $241,075.18 |
| 13 | $22,754.45 | $7,299.48 | $15,454.97 | $233,775.70 |
| 14 | $22,754.45 | $7,788.34 | $14,966.11 | $225,987.36 |
| 15 | $22,754.45 | $8,309.94 | $14,444.51 | $217,677.42 |
| 16 | $22,754.45 | $8,866.47 | $13,887.98 | $208,810.95 |
| 17 | $22,754.45 | $9,460.28 | $13,294.17 | $199,350.68 |
| 18 | $22,754.45 | $10,093.85 | $12,660.60 | $189,256.83 |
| 19 | $22,754.45 | $10,769.85 | $11,984.60 | $178,486.98 |
| 20 | $22,754.45 | $11,491.13 | $11,263.32 | $166,995.85 |
| 21 | $22,754.45 | $12,260.71 | $10,493.74 | $154,735.14 |
| 22 | $22,754.45 | $13,081.83 | $9,672.62 | $141,653.30 |
| 23 | $22,754.45 | $13,957.95 | $8,796.50 | $127,695.36 |
| 24 | $22,754.45 | $14,892.74 | $7,861.71 | $112,802.62 |
| 25 | $22,754.45 | $15,890.13 | $6,864.32 | $96,912.49 |
| 26 | $22,754.45 | $16,954.32 | $5,800.13 | $79,958.16 |
| 27 | $22,754.45 | $18,089.79 | $4,664.66 | $61,868.38 |
| 28 | $22,754.45 | $19,301.29 | $3,453.16 | $42,567.08 |
| 29 | $22,754.45 | $20,593.94 | $2,160.51 | $21,973.15 |
| 30 | $22,754.45 | $21,973.15 | $781.30 | $0.00 |
The basics
What is amortization?
Amortization is the process of paying off a loan with a series of equal payments, each one split between interest on what you still owe and principal that chips away at the balance. The payment stays the same, but the split inside it shifts every month — heavy on interest at the start, heavy on principal by the end.
payment = interest + principal
One payment, two parts
Every scheduled payment first covers the interest owed that month; whatever is left pays down the principal. The payment is fixed, so the two parts trade places over time.
$1,896 = $1,625 interest + $271 principal
interest = balance × monthly rate
Interest follows the balance
Because interest is charged on the remaining balance, it is biggest at the start and shrinks as the loan is paid down — which is why a schedule front-loads the interest.
$300,000 × 0.5417% = $1,625 first month
Method
How the payment formula works
Four steps turn a loan amount, a rate, and a term into the fixed monthly payment and the schedule beneath it.
- 1
Convert the rate to a monthly rate
Divide the annual rate by 12. A 6.5% APR becomes a monthly rate of about 0.5417% — the rate actually charged each period.
r = 6.5% ÷ 12 = 0.0054167 - 2
Count the number of payments
Multiply the term in years by 12 to get the total number of monthly payments.
n = 30 × 12 = 360 - 3
Apply the amortization formula
Plug the principal P, monthly rate r, and count n into the payment formula. It returns the one fixed payment that clears the loan in exactly n months.
M = P·r(1+r)ⁿ / ((1+r)ⁿ − 1) - 4
Split each payment and march the balance down
For each month, interest is the balance times r; principal is the payment minus that interest; subtract the principal from the balance and repeat until it hits zero.
interest = balance·r · principal = M − interest
The table
How to read the schedule
Each row is one payment. Five columns tell the whole story of where your money goes — and why the early years feel like they barely move the balance.
column 1
Payment number
The period, counting up from one to the last payment. In the yearly view each row instead sums a whole year of payments.
column 2
Payment
The fixed amount due that month — the same every period for a standard loan, plus any extra you choose to add.
column 3
Principal
The slice that actually reduces what you owe. It starts small and grows every month as the interest slice shrinks.
column 4
Interest
The slice charged on the outstanding balance. Largest at the start, it falls steadily — the mirror image of the principal column.
column 5
Remaining balance
What is left to repay after the payment. It glides down to exactly zero on the final row, which is the definition of a fully amortized loan.
the crossover
When principal overtakes interest
On long loans the principal slice does not exceed the interest slice for years. Watching the two columns cross is the clearest picture of a mortgage.
Worked examples
The formula across loan types
The same math runs a 30-year mortgage, a 5-year car loan, and a 3-year personal loan — only the amount, rate, and term change. Each tab computes the full result live.
$300,000 home loan
$300,000.00 at 6.5% APR over 30 years.
Monthly rate r = 6.5% ÷ 12 = 0.005417
Payments n = 30 × 12 = 360
Payment M = $300,000.00 · r(1+r)360 / ((1+r)360 − 1)
Month 1 split $1,625.00 interest + $271.20 principal
Monthly payment: $1,896.20Total interest: $382,633.47Total paid: $682,633.47Term: 30y
Where it applies
Loans that amortize
Any fixed-rate, fixed-term installment loan amortizes the same way. The schedule below fits all of them.
15–30 years
Mortgages
The classic amortized loan. Long terms mean interest dominates for years, which is why extra principal and refinancing have such a large effect on the total cost.
3–7 years
Auto loans
Shorter terms keep total interest modest, but a high rate on a long car loan still adds up. The schedule shows exactly how fast you build equity in the vehicle.
1–7 years
Personal & student loans
Unsecured personal loans and most student loans amortize on the same formula. Higher rates make the early-interest tilt even steeper.
Pay it down faster
The effect of extra payments
An extra dollar on the principal does more than its face value, because it erases all the future interest that dollar would have been charged. Add an extra payment in the tool above and the schedule shortens in front of you.
100% to principal
Extra goes straight to the balance
Because your regular payment already covers the month's interest, every extra dollar attacks the balance directly — and a smaller balance means less interest is charged next month.
$200 extra/mo on $300k at 6.5% → ~7 years sooner
the snowball
The saving compounds
Less interest next month means more of your fixed payment hits principal too, so the balance falls faster and faster. To model a target date, try the mortgage payoff calculator.
Tens of thousands in interest saved over the term
Worth knowing
Common mistakes and pitfalls
The errors that throw off a loan estimate — and the facts that keep the math honest.
rate ÷ 12, not rate
Use the monthly rate
The formula needs the monthly rate, not the annual one. Forgetting to divide the APR by 12 overstates the payment roughly twelvefold.
P + I only
The payment is not your whole bill
Amortization covers principal and interest. Property taxes, insurance, and PMI are added by the lender on top, so your actual mortgage bill is higher.
years × 12
Count payments, not years
n is the number of monthly payments, so a 30-year loan is 360, not 30. Mixing years and months is the most common slip.
front-loaded
Half the term ≠ half paid off
At the midpoint of a long mortgage you have paid far less than half the principal, because the early years were mostly interest. Read the balance column, not the calendar.
fixed-rate only
This assumes a fixed rate
An adjustable-rate loan re-amortizes whenever the rate changes. The schedule here assumes one rate for the whole term.
compound interest
Saving is not borrowing
Growing savings uses compound growth, not amortization. For that, use the compound interest calculator or the simple interest calculator.
Reference
The amortization formulas
The full set, so you can solve for whichever piece you need.
| To find | Formula |
|---|---|
| Monthly rate r | APR ÷ 12 (as a decimal) |
| Number of payments n | term in years × 12 |
| Monthly payment M | P·r(1+r)ⁿ / ((1+r)ⁿ − 1) |
| Payment when r = 0 | P ÷ n |
| Interest this period | balance × r |
| Principal this period | M − interest |
| New balance | balance − principal |
| Total paid | M × n |
| Total interest | (M × n) − P |
FAQ
Common questions
An amortization schedule is a table that lists every payment over the life of a loan and shows how each one is split between interest and principal, along with the balance left afterwards. Early payments are mostly interest because the balance is large; later payments are mostly principal as the balance shrinks. The schedule ends when the balance reaches zero.
The level monthly payment comes from the formula M = P·r(1+r)^n ÷ ((1+r)^n − 1), where P is the loan amount, r is the monthly interest rate (the APR divided by 12), and n is the number of payments (the term in years times 12). It is the fixed amount that exactly pays the loan off over n months. If the rate is 0%, the payment is simply the loan amount divided by the number of months.
Interest each month is charged on the balance you still owe, and at the start that balance is the whole loan. So the interest slice is largest at the beginning and the principal slice is small. As the balance falls, less interest is charged and more of the same fixed payment goes to principal — the split flips over time. On a 30-year mortgage you often do not cross the halfway point of paying down principal until around year 18 to 20.
Any extra you pay goes straight to principal, so the balance drops faster than scheduled. A smaller balance means less interest is charged next month, so more of your regular payment also attacks the principal — the effect compounds. The result is a shorter term and a large reduction in total interest. On a $300,000 loan at 6.5% over 30 years, an extra $200 a month can cut roughly seven years off the term and tens of thousands in interest.
The interest rate is the cost of borrowing the principal. The APR (annual percentage rate) folds in certain fees and points to give a fuller yearly cost, so it is usually a little higher than the bare rate. This calculator treats the figure you enter as the nominal annual rate and divides it by 12 to get the monthly rate. For a mortgage with points, enter the APR to approximate the all-in cost.
No. It calculates principal and interest only — the part of the payment that actually pays off the loan. Property taxes, homeowners insurance, HOA dues, and private mortgage insurance are added on top by your lender and vary by location and lender, so they are not part of the amortization math itself.
Negative amortization happens when your payment is smaller than the interest due that month, so the unpaid interest is added to the balance and the loan grows instead of shrinks. A properly amortized loan never does this — the payment always covers the interest with some left for principal. This calculator only models fully amortizing loans, so the balance always falls to zero.
Yes. The amortization formula is identical for any fixed-rate, fixed-term installment loan — mortgages, auto loans, personal loans, and most student loans all amortize the same way. Only the amount, rate, and term change. Enter your numbers and the schedule works exactly the same.
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Ugo CharlesBuilt and fact-checked against our editorial standards · Last updated June 2026
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