A fixed rate locks your payment for the life of the loan. A variable rate starts lower — and then moves with a market index, taking your payment with it. Neither is cheaper in the abstract: the fixed loan charges you a premium for certainty, and the variable loan hands you the interest-rate risk the lender would otherwise carry. This page compares the two over the full term, including the worked example most comparisons skip: what actually happens to your payment when a variable rate resets.
General information, not financial advice.
Fixed. The rate is set at signing and never changes. Every payment is known on day one, the amortization schedule printed at closing is the schedule you will actually live on, and budgeting is simple arithmetic.
Variable. The rate is an index plus a margin: a public benchmark — the Wall Street Journal prime rate (published in the Federal Reserve’s H.15 release) or SOFR (published by the Federal Reserve Bank of New York) — plus a fixed lender margin set in your note (ClearValue’s index-mechanics explainer describes the same construction). When the index moves, your rate moves by the same amount, typically at the next adjustment date. The margin never changes; the index does all the moving.
Variable comparisons usually stop at “your payment could go up.” Here is how much, on a realistic reset:
The shock is +$131.01 a month — about $9,400 over the remaining term if the rate stays there. Notice what the example assumes: a two-point index rise in one year, which is a bad year, not a worst case. The honest way to evaluate a variable loan is to run exactly this test at a rate two points above the start rate and ask whether the business still carries the payment comfortably. If it doesn’t, the lower starting rate is not a saving — it is a loan against your future cash flow.
Inside the SBA 7(a) program, “variable” is more constrained than in conventional lending: the rate is WSJ prime plus a spread, and the SBA caps the maximum spread a lender may charge. A bank’s conventional variable loan, by contrast, can carry whatever margin the contract says. The program’s spread caps and current rate bands live in the SBA eligibility hub and the rate snapshot in average business loan interest rates — the point here is that “variable” does not mean the same thing in every market.
The guidance across bank and broker explainers (Coti Funding, Biz2Credit) converges on a consistent pattern:
| Situation | Usually favours |
|---|---|
| Long term (7+ years) at a rate you can afford today | Fixed — a decade is a long time to hold rate risk |
| Thin margins, payment must never change | Fixed |
| Short horizon — you expect to repay, sell or refinance within a few years | Variable — you may exit before resets bite |
| Revolving use (line of credit), balances that rise and fall | Variable — lines are rarely offered fixed, and balances are temporary |
| You expect rates to fall and would benefit automatically | Variable — a fixed loan only benefits via refinancing |
Refinancing from variable to fixed is itself a named use case for refinancing — and it should pass the break-even test in when to refinance a business loan like any other refi. Whichever structure you choose, run it through the business loan calculator at both today’s rate and a stressed rate two points higher; the fixed loan’s numbers won’t move, which is precisely the comparison.
What is better, a variable or a fixed interest rate? PNC’s FAQ asks the same question, and the answer is conditional: fixed is better when you need payment certainty over a long term; variable is better when your horizon is short or your balance revolves, and you can absorb a reset. The decision input that matters most is the stressed payment — on $150,000 over 84 months, a reset from 7.5% to 9.5% after one year raises the payment from $2,300.74 to $2,431.76. If that payment breaks the budget, fixed is better for you, whatever the starting rate says.
Can a variable rate go down? Yes — the rate is index plus margin, and when the index falls, the rate falls by the same amount at the next adjustment (Live Oak Bank’s explainer makes the same point). That symmetry is the variable loan’s real upside: in a falling-rate period you benefit automatically, while a fixed-rate borrower must refinance — and pay closing costs — to capture the same decline.
Are SBA loans fixed or variable? Both exist. SBA 7(a) loans are commonly variable, priced as WSJ prime plus a spread the SBA caps; fixed-rate 7(a) loans are also available, generally at higher rates than the variable starting point. SBA 504 loans pair a bank loan with a CDC debenture whose rate is fixed for the debenture’s 10-, 20- or 25-year life.
Sources: ClearValue, variable-rate index mechanics (WSJ prime via Federal Reserve H.15; SOFR via the Federal Reserve Bank of New York); PNC, fixed vs variable FAQ; Live Oak Bank, variable rate explainer; Coti Funding and Biz2Credit, rate-type decision guidance; banks.com, business loan rate types. Payment-shock scenario computed from the amortization formula. Currency verified 2026-10-23.