What a $100,000 Loan Really Costs Over 5 Years

The cost of borrowing $100,000 over a five-year term is highly sensitive to interest rates—what you pay each month and how much interest accumulates depends directly on the APR. The table below shows how monthly payments and total interest vary across a range of APRs for this specific loan structure.

$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

Understanding the numbers in this scenario reveals a clear trade-off: higher interest rates dramatically increase both the monthly payment and the total interest paid over time. For example, a loan at 5% APR results in a monthly payment of approximately $1,775 and total interest of $10,200—less than 10% of the principal. In contrast, at 12% APR, the monthly payment rises to about $2,223, and total interest reaches $13,200—nearly 13% of the principal. This difference may seem small at first, but over five years, it translates into significantly higher costs and reduced cash flow for borrowers. A key insight is that even small increases in APR can strain a business’s budget. For instance, moving from 7% to 8% APR raises the monthly payment by about $130 and increases total interest by $1,800. This kind of gap is especially impactful for small businesses with tight operating margins or those using the loan to cover working capital. The same applies to a business planning to use the loan for equipment or inventory—higher interest means more of its revenue is consumed by debt service. Importantly, the loan term of five years is relatively short compared to typical business loans (which often span 3 to 10 years), so borrowers benefit from lower overall interest exposure. However, this doesn’t eliminate the need to compare APRs carefully. A 5% APR loan at $100,000 over five years is nearly 40% cheaper in total interest than a 10% APR loan, which is a substantial difference in real-world terms. Another consideration is the stability of the APR. While the table assumes a fixed rate, in reality, some loans may have variable rates that rise with market conditions. For borrowers, this introduces uncertainty—especially in volatile economic environments. A fixed-rate loan at 5% APR offers predictable payments, while a variable-rate loan at 7% might spike to 10% or more, increasing both monthly costs and total interest. For businesses evaluating a $100,000 five-year loan, the decision should not be based solely on the APR. It must also consider the business’s cash flow, future revenue projections, and risk tolerance. A higher APR might be acceptable if the loan is used for a high-growth project, but it becomes problematic if the business lacks the ability to service the debt in the short term. How we calculated this: We used the standard loan amortization formula: Monthly payment = P × [r(1+r)^n] / [(1+r)^n – 1] Where P = $100,000, r = monthly interest rate (APR ÷ 12), and n = number of months (5 years × 12). Total interest = (Monthly payment × n) – P. This method is consistent with standard financial modeling and reflects real-world loan structures. The results are based on a fixed-rate, level-payment loan with no prepayment penalties or fees.