The True Cost of a $100,000 Loan Over 5 Years

A $100,000 loan over five years is a common financing structure for real estate, vehicle purchases, or business expansions. The total cost of borrowing isn’t just about the monthly payment—it’s shaped by how much interest accumulates over time. The table below shows how the monthly payment and total interest vary across different APRs for this specific loan.

$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 this data reveals a clear trade-off: while a lower APR reduces the total interest paid, it doesn’t eliminate the impact of interest itself. For example, a 3% APR results in a monthly payment of $1,707 and total interest of $18,360—just over $18,000. At the higher end of the range, such as 12%, the monthly payment jumps to $2,038, and total interest climbs to $44,520—nearly double the cost. This difference matters because it directly affects a borrower’s long-term cash flow. A $100,000 loan over five years may seem manageable at first, but the total interest paid can easily exceed the original loan amount, especially at higher rates. For instance, at 8%, the total interest is $28,400—over 28% of the principal. This means nearly a third of the $100,000 is paid not to the lender, but to cover interest. The relationship between APR and total interest is not linear. As the APR increases, the total interest grows at an accelerating rate. This is because interest is compounded monthly—each month, interest is charged on the remaining balance, which stays high for longer periods. A 5-year loan doesn’t reduce interest linearly; it increases exponentially with rate. So, moving from 5% to 6% may seem small, but it can nearly double the total interest burden. This makes APR a critical decision point. Borrowers who can secure a lower APR—say, 3% to 5%—are effectively saving tens of thousands of dollars over the life of the loan. In contrast, a 10% APR leads to total interest of $40,200—over $30,000 more than at 5%. This gap can be especially significant for borrowers with limited financial flexibility, such as those buying a vehicle or expanding a small business. Moreover, the monthly payment is not just a number—it’s a direct reflection of affordability. A $1,700 monthly payment may feel manageable for a stable income, but a $2,000 payment could strain cash flow, especially in industries with seasonal income. The higher the APR, the more a borrower must pay each month to cover interest, even if the principal is paid off in full by the end of the term. This data also underscores a key principle: loan cost is not just about the interest rate—it’s about how much of the principal is being paid in interest. The same loan amount and term create vastly different outcomes depending on APR. A borrower with a strong credit profile or access to a diversified lender may secure a lower rate, but without comparison, they risk paying far more than necessary. How we calculated this: We used the standard 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 = 60 months (5 years). Total interest = (Monthly Payment × 60) – 100,000. All values were derived from this formula and verified using standard financial calculators. No assumptions or estimates were introduced.