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• Debt & financing

Interest &
Amortization

Follow the repayment arc from the first payment through the final balance.

Repayment picture

Monthly payment
?
A scheduled paydown of a loan over time, usually splitting each payment between interest and principal.
$2,955.44
Your regular cash commitment
Total interest
?
The borrowing rate the business pays on debt, often adjusted for the tax benefit of interest.
$583,959.32
What borrowing costs over time
Total paid
$1,063,959.32
Loan amount plus interest

Repayment arc

Interest gives way to principal over time

InterestPrincipal
Principal and interest over the repayment termYear 1Year 15Year 30

First-year schedule

#PaymentPrincipalInterestBalance
1$2,955.44$455.44$2,500.00$479,544.56
2$2,955.44$457.81$2,497.63$479,086.74
3$2,955.44$460.20$2,495.24$478,626.54
4$2,955.44$462.60$2,492.85$478,163.95
5$2,955.44$465.01$2,490.44$477,698.94
6$2,955.44$467.43$2,488.02$477,231.52
7$2,955.44$469.86$2,485.58$476,761.65
8$2,955.44$472.31$2,483.13$476,289.34
9$2,955.44$474.77$2,480.67$475,814.58
10$2,955.44$477.24$2,478.20$475,337.33
11$2,955.44$479.73$2,475.72$474,857.61
12$2,955.44$482.23$2,473.22$474,375.38
Repayment analysis charts
Methodology

Methodology keeps the payment math visible. The selected amortization method controls how each payment is split between interest and principal, while the schedule shows the balance after each period.

Payment formula (PMT)
PMT=Pr(1+r)n(1+r)n1PMT = P \cdot \frac{r(1+r)^n}{(1+r)^n - 1}
French (constant payment)
PMT=Pr(1+r)n(1+r)n1PMT = P \cdot \frac{r(1+r)^n}{(1+r)^n - 1}

References

  1. Irving Fisher, The Theory of Interest, 1930.Reference context for time value of money, discounting, present value, and interest-rate mathematics.
  2. Consumer Financial Protection Bureau, Regulation Z, Appendix J to Part 1026.Reference context for actuarial closed-end-credit rate and payment calculations; not legal-compliance advice.

For educational and informational purposes only. Not financial advice.