Business & SBA Loan Calculator

• Models the SBA guarantee fee either financed into the loan or paid upfront at closing.
• Optionally estimates a debt service coverage ratio (DSCR) from the business's net operating income.
• Shows a full year-by-year amortization table alongside the summary numbers.
• Works for any fixed-rate business term loan, not only SBA-guaranteed ones.

How to use this calculator

Enter the loan amount, quoted interest rate, and term. Under Advanced, set the SBA guarantee fee percentage and whether it's financed into the loan balance or paid in cash at closing — financing it raises the loan balance slightly but avoids needing that cash upfront. Optionally enter the business's annual net operating income to see an estimated debt service coverage ratio.

How the estimate works

The guarantee fee is calculated first, since it can change the amount actually being amortized:

Guarantee fee     = loan amount × guarantee fee %
Amount financed   = loan amount + guarantee fee (if financed), else loan amount alone
Monthly payment   = standard amortizing payment on the amount financed

Debt service coverage ratio, when net operating income is provided, divides that income by the loan's total annual payments (principal plus interest):

DSCR = annual net operating income ÷ annual debt service

A worked example

A $250,000 loan at 11.5% over 10 years, with a 3.5% guarantee fee financed into the balance, amortizes a $258,750 loan into a monthly payment in the mid-$3,000s. With $60,000 in annual net operating income against that payment, the DSCR comes out comfortably above the 1.25 threshold many SBA lenders look for.

Understanding debt service coverage ratio

DSCR measures how many times over a business's operating income could cover its debt payments — a ratio of 1.25 means income covers the debt service with 25% to spare. Many SBA lenders look for a DSCR of at least 1.25 as a cushion against a slow month or year; a ratio below 1.0 means the business's operating income alone wouldn't cover the loan payment at all, which is typically a hard obstacle to approval without additional collateral or income sources.

Assumptions and limitations

• Uses one flat interest rate for the whole term. Some business loans carry a variable rate tied to prime, which this doesn't model.
• DSCR uses net operating income as entered. Lenders typically define this specifically as income after operating expenses but before debt service — using revenue instead will overstate the ratio significantly.
• Doesn't model other loan fees beyond the SBA guarantee fee, such as packaging fees, appraisal costs, or closing costs a specific lender might charge.

Common mistakes

Using revenue instead of net operating income for DSCR. This dramatically overstates how well a business can cover its debt payments — lenders look at income after operating expenses, not top-line revenue.

Treating a quoted rate as guaranteed. SBA loan pricing is typically the base rate (often prime) plus a lender spread, and the final approved rate and terms depend on underwriting specific to the borrower and the lender.

Not accounting for the guarantee fee when budgeting closing cash. If the fee isn't financed into the loan, it needs to be available in cash at closing — a detail easy to overlook when focused on the monthly payment alone.

Frequently asked questions