Mortgage Amortization Schedule Calculator
Generate a detailed month-by-month mortgage amortization schedule. Calculate your starting balance, principal paid, interest paid, and ending balance.
Inputs
Detailed Monthly Schedule (First 36 Months)
| Month | Starting Balance | Payment | Principal | Interest | Ending Balance |
|---|---|---|---|---|---|
| Enter valid inputs to view schedule | |||||
Results Summary
Understanding Amortization Schedules
A Mortgage Amortization Schedule is a complete table showing the breakdown of every monthly payment over the entire life of your mortgage. For each month, the schedule details your starting principal balance, the total payment, the portion of the payment applied to principal, the portion allocated to interest, and the remaining ending balance.
This table is incredibly helpful for visualizing how your mortgage debt behaves over time. At the beginning of a 30-year term, your payments are highly inefficient, with interest accounting for over 80% of the total amount. However, as the principal balance decreases, the monthly interest charge declines, allowing more of your payment to go toward principal. This mortgage amortization schedule calculator displays this monthly breakdown clearly.
Amortization Schedule Formulas
To construct a monthly amortization table, the following equations are applied sequentially for each payment period:
1. Monthly Interest Amount
\[I_t = B_{t-1} \cdot \frac{r}{12}\]Where \(I_t\) is the interest paid in month \(t\), and \(B_{t-1}\) is the balance from the previous month.
2. Principal Amount
\[P_t = PMT - I_t\]Where \(P_t\) is the principal paid, and \(PMT\) is the fixed monthly payment.
3. New Outstanding Balance
\[B_t = B_{t-1} - P_t\]Detailed Amortization Table Example
Let's run a calculation for a $250,000 mortgage at a fixed rate of 6.25% and a 30-year term. The monthly payment is $1,539.29:
| Month | Starting Balance | P&I Payment | Principal Portion | Interest Portion | Ending Balance |
|---|---|---|---|---|---|
| Month 1 | $250,000.00 | $1,539.29 | $236.79 | $1,302.50 | $249,763.21 |
| Month 2 | $249,763.21 | $1,539.29 | $238.02 | $1,301.27 | $249,525.19 |
| Month 3 | $249,525.19 | $1,539.29 | $239.26 | $1,300.03 | $249,285.93 |
As you can see, the interest portion declines by about $1.25 between Month 1 and Month 2, which is diverted directly to paying down more principal. While this shift seems minor, it compounds over 360 payments to fully pay off the debt.
Frequently Asked Questions (FAQ)
What is a monthly amortization schedule?
A monthly amortization schedule is a chronological table that lists every single payment on a loan, detailing how much of each payment goes toward interest versus principal, and the outstanding balance remaining after each payment is made.
How do I read an amortization schedule?
Read the table from left to right. Locate the month number, check your starting balance, verify the fixed monthly payment, review the principal and interest breakdown, and see your new ending balance after that payment.
How is the interest portion calculated on a schedule?
Interest is calculated by multiplying your outstanding principal balance by your annual interest rate, then dividing by 12 months. This is why interest payments are highest when the loan balance is highest.
How is the principal portion calculated on a schedule?
The principal portion is calculated by subtracting your monthly interest charge from your total monthly P&I payment. The remaining funds are applied to reduce the outstanding loan balance.
Does the monthly payment change on a fixed amortization schedule?
No. On a fixed-rate mortgage, the total monthly principal and interest payment remains exactly the same. Only the internal allocation between principal and interest changes each month.
How can I use an amortization schedule to pay off my loan early?
By adding extra principal payments, you can track how those payments lower your balance. This lets you see how many months you cut off the end of your schedule and your total interest savings.
What is negative amortization?
Negative amortization occurs when your monthly payment is less than the monthly interest charge due. The unpaid interest is added to your loan balance, causing your outstanding debt to grow rather than shrink.
Are taxes and insurance included in an amortization schedule?
No. Amortization schedules only model the principal and interest (P&I) payments. Property taxes, homeowners insurance, and HOA fees do not amortize and are excluded from the table.
Can I get an amortization schedule for a HELOC?
HELOCs typically do not have a fixed amortization schedule during their draw period, as payments are interest-only and rates are variable. Once the repayment period begins, they amortize based on the balance and rate at that time.
What is a balloon payment amortization schedule?
A balloon schedule calculates monthly payments as if the loan were amortized over a long term (like 30 years), but requires the borrower to pay off the entire remaining balance in a single lump-sum 'balloon' payment at the end of a shorter period (e.g. 5 or 7 years).