ReckonBoxWhat an amortization schedule shows
An amortization schedule breaks every loan payment into two parts: the interest charged on the balance that period, and the principal that actually pays the loan down. The payment stays fixed, but the split inside it shifts month after month, and watching that shift is the point of the schedule.
On a $300,000 loan at 7% over 30 years, the payment is $1,995.91. The first one carries $1,750 of interest and just $246 of principal. Thirty years later the last payment is almost all principal. Every calculator prints this table. Few tell you the one number inside it that matters.
The month principal finally wins
On a 30-year loan at a typical rate, more of each payment goes to interest than to principal until well past the halfway mark. For the default loan, that crossover lands at payment 242, part way through year 21. Only then does the balance start falling faster than the interest piles on.
Bankrate hints at this, putting the tipping point "around year 18 to 19" for its example. calculator.net and amortization-calc.com draw a chart and leave you to eyeball it. This page gives the exact payment number, because it changes how the early years read: for two decades, the loan is mostly renting money, not buying equity.
Year one makes the imbalance concrete. Of the $23,951 you pay in the first twelve months, $20,903 is interest and $3,047 pays down the balance:
| First year of the $300,000 loan | |
|---|---|
| Interest paid | $20,903 |
| Principal paid | $3,047 |
| Balance cleared | 1.0% |
Why the early payments are almost all interest
Interest each month is the monthly rate times the outstanding balance, and the balance is largest at the start, so the interest charge is largest then too. The fixed payment has to cover that first, and whatever is left pays principal.
As the balance drops, the interest charge drops with it, freeing more of the same payment for principal. That feeds on itself: more principal paid means a smaller balance next month, which means less interest, which means still more principal. The curve is slow at first and then steepens, which is exactly why the crossover sits so late.
Where the numbers come from
The monthly payment is the amortizing-payment formula: payment equals P times i times (1 plus i) to the power n, divided by (1 plus i) to the power n minus 1, where P is the loan, i the monthly rate, and n the number of months. The schedule then walks the loan month by month, charging interest on the running balance, subtracting the principal, and recording the year-end totals.
The crossover is the first month where the principal portion exceeds the interest portion. At a 0% rate there is no interest to overtake, so the schedule is a flat repayment and the crossover does not exist.
What this does not cover
This tool shows a loan exactly as written, so you can read its structure. It does not model extra payments, a biweekly schedule, or a lump sum, because those change the loan rather than describe it, and they have their own tool. The mortgage payoff calculator answers what an extra $200 a month or a biweekly plan would save in interest and years.
Nor is any of this advice about which loan or term to take. A schedule is a fact about a set of numbers, not a verdict on them. For a decision that turns on your own finances, a lender or a CPA is the right call.
Frequently asked questions
What is an amortization schedule? An amortization schedule is a table that breaks every loan payment into the interest charged that period and the principal that pays the balance down. The interest portion is the periodic rate times the outstanding balance, and the principal is whatever is left of the fixed payment, so as the balance falls the interest shrinks and more of each payment goes to principal.
When does principal exceed interest on a loan? Later than most people expect. On a $300,000 loan at 7% over 30 years, more of the payment goes to interest than to principal until payment 242, part way through year 21. Before that the balance falls slowly: in year one, $20,903 of the payments is interest and only $3,047 pays down principal.
How is the monthly payment calculated? By the amortizing-payment formula: payment equals P times i times (1 plus i) to the power n, all divided by (1 plus i) to the power n minus 1, where P is the loan, i the monthly rate, and n the number of months. On $300,000 at 7% over 30 years that is $1,995.91 a month.
Why is so much early payment interest? Because interest is charged on the balance, and the balance is at its largest at the start. On the default loan the first payment carries $1,750 of interest against $246 of principal. The split only evens out as the balance drops, which is why an amortization schedule looks so lopsided in the early years.
How much total interest will I pay? On a $300,000 loan at 7% over 30 years, the total interest is about $418,527, more than the amount borrowed, for total payments near $718,527. A shorter term or a lower rate cuts that sharply, which is why the schedule is worth checking before signing rather than after.
What is the difference between this and the mortgage payoff calculator? This tool shows the schedule of a loan as written, so you can see the principal and interest split and when it flips. The mortgage payoff calculator answers a different question: what an extra monthly payment, a lump sum, or a biweekly schedule would save in interest and time. Use this to understand the loan, that one to accelerate it.