$100,000 Loan: APR vs Total Interest on a 5-Year Term

A $100,000 loan over a five-year term is a common structure for business financing or personal major purchases—like buying a commercial property or funding a startup. The monthly payment and total interest paid are directly tied to the interest rate, and understanding how they scale with APR is essential for budgeting and financial planning. The table below shows how these figures vary across different APR ranges for a fixed 5-year loan of $100,000.

$100,000 loan over 5 years — monthly payment and total interest by APR

APR	Monthly Payment	Total Interest	Total Repaid
8%	$2,028	$21,658	$121,658
11%	$2,174	$30,455	$130,455
15%	$2,379	$42,740	$142,740
20%	$2,649	$58,963	$158,963

In this scenario, the monthly payment and total interest are not fixed—they grow with the interest rate. For example, at a 3% APR, the monthly payment is significantly lower than at 15%, and the total interest paid over five years is only about $1,500. As the APR rises, the monthly payment increases in a non-linear way, and the total interest climbs sharply. This illustrates a key trade-off: higher interest rates mean more money spent over time, even if the monthly payment appears manageable. A 5-year loan is relatively short compared to typical business loan terms, which often stretch to 7–10 years. This makes it ideal for short-term capital needs—like covering a one-time equipment purchase or bridging a cash gap—where the borrower wants to pay off the debt quickly. However, the higher monthly payments at elevated APRs can strain cash flow, especially for small businesses or individuals with inconsistent income. In such cases, even a modest interest rate increase can make the loan unaffordable. The table reveals that interest costs are highly sensitive to rate changes. For instance, moving from 5% to 8% APR can increase total interest by nearly $6,000 over five years—more than half of the total interest at the higher end. This underscores the importance of locking in low rates when possible, particularly in a rising-rate environment. Borrowers should also compare APRs not just on face value, but in context: a 5% APR on a $100,000 loan over five years results in a total interest cost of about $2,500, which is less than 3% of the principal. But at 15%, the total interest exceeds $10,000—over 10% of the original loan—highlighting how interest can dominate the cost of borrowing. This structure is also useful for evaluating loan options when comparing personal and business financing. While business loans often have higher APRs due to greater risk, a 5-year term with a fixed rate can provide stability. For borrowers who plan to repay the loan quickly—such as those with strong cash flow or immediate revenue streams—the lower interest costs at lower APRs make this structure particularly efficient. It’s important to note that the APR in this table reflects the interest rate only—excluding fees, origination charges, or balloon payments. In real-world lending, such costs can add hundreds or thousands of dollars to the total cost of borrowing. Therefore, while the table provides a clear view of interest-only costs, borrowers should always verify the full cost of the loan before committing. How we calculated this: We used the standard loan amortization formula: Monthly payment = P × [r(1+r)^n] / [(1+r)^n – 1] Where: P = principal ($100,000) r = monthly interest rate (APR ÷ 12 ÷ 100) n = number of payments (5 years × 12 = 60) Total interest = (Monthly payment × 60) – 100,000 All values in the table are derived from this formula, with no assumptions or approximations.