Home › Business Acquisition Loan Calculator: How to Model an Acquisition (2026)

Business Acquisition Loan Calculator: How to Model an Acquisition (2026)

Quick Answer

To model a business acquisition loan, you need a handful of inputs: the purchase price, the down payment (buyer equity injection), the loan amount(s) and type(s), the interest rate(s), the amortization term(s), and the business’s normalized cash flow (SDE or EBITDA). From those you calculate the monthly debt-service payment (using a standard amortization formula), then the debt-service-coverage ratio (DSCR), the business’s cash flow available for debt service divided by total annual debt payments, which is the test of whether the deal is financeable. Lenders generally want a DSCR comfortably above 1.0x, often 1.25x or higher, so there’s cushion for a downturn plus a reasonable owner salary. A simple worked example: a $1M business with $250K of SDE, bought with $100K buyer equity + $50K standby seller note + $850K SBA 7(a) at ~11% over 10 years, monthly payment roughly $11,700, annual debt service roughly $140K, DSCR roughly 1.8x before owner salary or about 1.1x-1.3x after a reasonable salary, financeable but with modest cushion. The calculator tells you if the deal is fundable; it can’t tell you if it’s a good business or a fair price, that’s diligence and valuation.

A business acquisition loan calculator is a structuring tool, not a verdict, it tells you whether a deal can be financed at a given price and structure, not whether the business is worth buying. But running the numbers is the first reality check on any acquisition: if the deal doesn’t cover its debt service with cushion, the price or structure has to change. This page walks through the inputs that matter, the DSCR test that governs financeability, and a worked example.

We are CT Acquisitions, a buy-side M&A advisory firm. This is general orientation, not lending advice; confirm the numbers with an SBA-preferred lender. For the financing details, see business acquisition loan and acquisition loan rates; for what to pay, determining a fair acquisition price; for finding deals, how to find businesses for sale. If you’re an owner exploring a sale, our free valuation tool gives a sector-adjusted estimate.

Free Valuation Tool → Book a 30-Min Call Read: Broker Alternative

What this guide covers

Inputs you need: purchase price, down payment, loan amount(s) and type(s), interest rate(s), amortization term(s), normalized cash flow (SDE or EBITDA)
The key output: the debt-service-coverage ratio (DSCR), cash flow available for debt service ÷ total annual debt payments
The financeability test: lenders generally want DSCR comfortably above 1.0x, often 1.25x+, after a reasonable owner salary
Monthly debt service comes from a standard amortization formula, longer terms mean lower payments and a more comfortable DSCR
The calculator tells you if the deal is fundable, not if the business is good or the price is fair, that’s diligence and valuation
If the DSCR is too thin: re-trade the price, increase the down payment, lengthen the term, or add standby on the seller note, don’t just hope

The inputs that matter

Purchase price (enterprise value). What you’re paying for the business. Sanity-check it against sector norms, see determining a fair acquisition price.
Down payment / buyer equity injection. Your cash into the deal. For an SBA 7(a) acquisition, typically ~10% (part of which can be a standby seller note); for a conventional loan, ~20-30%+.
Loan amount(s) and type(s). Usually a stack, e.g., SBA 7(a) senior debt + a seller note + buyer equity. Each piece has its own rate and term.
Interest rate(s). SBA 7(a) is typically prime + a spread (variable); conventional is borrower- and deal-specific; the seller note is negotiated. Get quotes; don’t guess.
Amortization term(s). SBA business-only acquisitions typically amortize over 10 years (up to 25 if real estate is included); conventional over 5-7 years; seller notes over 3-7 years. The term drives the monthly payment.
Normalized cash flow (SDE or EBITDA). The business’s earnings, normalized for owner add-backs and one-time items, this is what has to cover the debt. For owner-operated businesses, SDE; for larger businesses with a management layer, EBITDA. Verify this against tax returns.
Owner salary / management cost. Subtract a reasonable salary for whoever will run the business (you, or a hired manager) before testing whether the remaining cash flow covers debt service. Lenders do this; you should too.
Working-capital needs and capex. The business may need cash to operate (inventory, receivables) and to maintain its assets, factor a reserve and ongoing capex into the model.

The math: monthly payment, then DSCR

Step 1, monthly payment per loan. Use the standard amortization formula: for a loan of principal P, monthly rate r (annual rate ÷ 12), and n months, the monthly payment M = P × r × (1+r)^n / ((1+r)^n − 1). Sum the monthly payments across all loans in the stack (SBA loan, seller note, etc.); multiply by 12 for total annual debt service.

Step 2, DSCR. DSCR = (cash flow available for debt service) ÷ (total annual debt service). ‘Cash flow available for debt service’ is typically normalized EBITDA, or SDE minus a reasonable owner salary, minus a maintenance-capex reserve, minus a working-capital reserve. Lenders generally want this ratio comfortably above 1.0x, often 1.25x or higher, the cushion absorbs a normal downturn and leaves room for the owner.

Step 3, stress-test it. Re-run the DSCR with revenue down 10-20%, or with the variable rate up 1-2 points, or with a key customer lost. If the deal goes underwater under a realistic stress scenario, it’s too leveraged at that price and structure.

A worked example

Target: a service business with $250,000 of normalized SDE, asking $1,000,000 (4x SDE).

Structure: $100,000 buyer equity (10%) + $50,000 seller note on standby (5%) + $850,000 SBA 7(a) loan (85%).
SBA loan terms: ~11% variable rate, 10-year amortization. Monthly payment ≈ $850,000 × 0.00917 × (1.00917)^120 / ((1.00917)^120 − 1) ≈ ~$11,700/month, ≈ $140,000/year.
Seller note: on full standby for the SBA-required period, so $0 of payments in the near term; after standby, modest payments at the negotiated rate.
Cash flow available for debt service: $250,000 SDE − $90,000 reasonable owner salary − $15,000 maintenance-capex reserve − $5,000 working-capital reserve ≈ $140,000.
DSCR: $140,000 ÷ $140,000 ≈ 1.0x after a reasonable owner salary. That’s tight, a lender would want more cushion. Fixes: re-trade the price to ~$850K-$900K (lowering the loan and the debt service), increase the buyer equity, lengthen the amortization (not usually possible beyond 10 years for SBA business-only), or take a lower owner salary in the early years (risky).
Better-structured version: price at $850,000, $100,000 buyer equity + $75,000 standby seller note + $675,000 SBA loan. Annual debt service ≈ $111,000. DSCR ≈ $140,000 ÷ $111,000 ≈ 1.26x after owner salary, financeable with reasonable cushion.

The lesson: at a given price, the structure (down payment, term, standby) can move a thin deal to a financeable one, but if the price is too high, no structure fixes it. The calculator surfaces that; only re-trading the price (or walking away) resolves it.

What the calculator can’t tell you

Whether the business is good. Customer concentration, owner dependency, declining trends, regulatory exposure, the calculator assumes the SDE is real and sustainable. Diligence verifies that.
Whether the price is fair. A deal can be perfectly financeable at an over-market price if you put enough down, financeable doesn’t mean a good buy. Compare the price to sector norms.
Whether the cash flow is sustainable. The calculator uses a number; diligence (and ideally a quality-of-earnings review) tests whether that number holds up.
Whether you can actually run it. The model assumes a competent operator; if you (or your team) can’t run the business, the cash flow erodes.
The deal terms beyond the loan. Earnouts, escrow holdbacks, working-capital adjustments, non-compete scope, transition arrangements, these affect what you actually pay and get, and the loan calculator doesn’t see them.

How we know this: the ranges, structures, and dynamics on this page come from the acquisitions we work on and the buyer mandates in our network of 100+ active capital partners, plus the founder-owned businesses we source for them. They are informed starting points, not guarantees, the specifics of your deal control your outcome. For owners weighing a sale, our free 90-second valuation tool gives a sector-adjusted estimate.

How to use the model in practice

Run the base case at the asking price and a realistic structure. If the DSCR is below ~1.25x after a reasonable owner salary, the deal needs work.
Stress-test it, revenue down 10-20%, rate up 1-2 points, key customer lost. If it goes underwater, it’s too leveraged.
Find the financeable price. Solve for the purchase price that gives you a comfortable DSCR at your available down payment, that’s your walk-away ceiling, regardless of the asking price.
Compare structures. More down vs longer term vs more standby on the seller note, which gets you to a comfortable DSCR with the least cash and risk?
Take it to a lender early. Get pre-qualified before you go deep on a target; the lender’s model will tell you what they’ll actually fund.
Then do the diligence and the valuation, the calculator says ‘fundable’; diligence and valuation say ‘good business, fair price.’ You need all three.

For what to pay, see determining a fair acquisition price; for evaluating the target, how to evaluate a small business for acquisition and due diligence questions when buying a business. If you’re an owner getting offers, our free valuation tool tells you whether the buyer’s price and structure are reasonable.

Sanity-Check the Price

Financeable doesn’t mean fairly priced

The calculator says ‘fundable’; a valuation says ‘fair price.’ If you’re an owner getting offers, knowing the defensible value tells you whether the buyer’s number is reasonable. Free, 90 seconds, no email gate.

Get a Free Valuation →

The five pillars of how CT Acquisitions works

$0 to Sellers

Buyer pays our fee. Founders never write a check.

No Retainer

No engagement letter. No upfront cost. No exclusivity contract.

100+ Capital Partners

Search funders, family offices, lower-middle-market PE, strategics.

Sequential, Not Auction

Confidential introductions to the right buyers. No bidding war.

60-120 Day Close

Not 9-12 months. Not 18 months. Months, not years.

No Pitch · No Pressure

Buying or selling, let’s talk

Whether you’re acquiring and want help modeling and structuring the deal, or you’re an owner evaluating an offer, we’ll walk you through it. No engagement letter, no retainer, no obligation.

Start a Confidential Conversation →

Frequently asked questions

How do you calculate a business acquisition loan?

Start with the inputs: purchase price, down payment (buyer equity injection), loan amount(s) and type(s), interest rate(s), amortization term(s), and the business’s normalized cash flow (SDE or EBITDA). Use the standard amortization formula to compute the monthly payment on each loan (M = P × r × (1+r)^n / ((1+r)^n − 1), where P is principal, r is the monthly rate, n is months), sum them, and multiply by 12 for annual debt service. Then calculate the debt-service-coverage ratio (DSCR): cash flow available for debt service (normalized EBITDA, or SDE minus a reasonable owner salary, minus capex and working-capital reserves) divided by annual debt service. Lenders generally want DSCR comfortably above 1.0x, often 1.25x+.

What DSCR do I need for a business acquisition loan?

Lenders generally want a debt-service-coverage ratio comfortably above 1.0x, often 1.25x or higher, calculated after subtracting a reasonable owner salary (and ideally a maintenance-capex reserve and a working-capital reserve) from the business’s cash flow. A DSCR right at 1.0x means the business exactly covers its debt with no cushion, lenders consider that too thin. Above 1.25x gives room for a normal downturn plus the owner’s compensation. If a deal’s DSCR is below that at the proposed price and structure, the fix is re-trading the price, increasing the down payment, lengthening the amortization, or adding standby on the seller note, not just hoping.

How much can I borrow to buy a business?

For an SBA 7(a) acquisition loan, up to roughly 90% of the project cost (with a typical 10% buyer equity injection, part of which can be a standby seller note), subject to the SBA’s maximum loan size. For a conventional bank acquisition loan, typically 70-80% (with 20-30%+ down), depending on the borrower’s credit, the deal, and the lender. The real constraint isn’t the percentage, it’s the debt-service-coverage ratio: the business’s cash flow has to cover all the layered debt with cushion after a reasonable owner salary. Model the DSCR before assuming you can borrow the maximum.

What’s the monthly payment on a business acquisition loan?

It depends on the loan amount, the interest rate, and the amortization term. Use the standard amortization formula: monthly payment = P × r × (1+r)^n / ((1+r)^n − 1), where P is the principal, r is the monthly interest rate (annual rate ÷ 12), and n is the number of months. As a rough example, an $850,000 loan at about 11% over 10 years (120 months) has a monthly payment of roughly $11,700, or about $140,000 a year. A longer amortization term lowers the monthly payment (and improves the DSCR); a shorter term raises it.

Can a loan calculator tell me if an acquisition is a good deal?

No. A loan calculator tells you whether a deal is financeable, whether the business’s cash flow covers the debt service with cushion at a given price and structure. It can’t tell you whether the business is good (customer concentration, owner dependency, declining trends, regulatory exposure), whether the price is fair (a deal can be financeable at an over-market price if you put enough down), whether the cash flow is sustainable (diligence and a quality-of-earnings review test that), or whether you can actually run the business. A financeable deal can still be a bad acquisition. You need the calculator plus diligence plus a valuation.

What inputs do I need to model a business acquisition?

The purchase price; the down payment (buyer equity injection); the loan amount(s) and type(s) in the financing stack (SBA loan, conventional loan, seller note, etc.); the interest rate(s) on each; the amortization term(s) on each; the business’s normalized cash flow (SDE for owner-operated businesses, EBITDA for larger ones, verified against tax returns); a reasonable salary for whoever will run the business; and reserves for maintenance capex and working capital. From those you compute monthly debt service, annual debt service, and the debt-service-coverage ratio, and you stress-test the DSCR under a downturn scenario.

How do I know what price makes an acquisition financeable?

Solve for it. Take your available down payment and a comfortable target DSCR (say 1.3x after a reasonable owner salary), and work backward to the purchase price that produces that DSCR given the loan terms you can get. That price is your walk-away ceiling, regardless of the asking price. If the asking price is above your financeable price, you either negotiate the price down, find more equity, or pass. A lender’s pre-qualification will give you a concrete sense of what they’ll fund; do your own model first so you walk in knowing the numbers.

What should I do if the acquisition loan numbers don’t work?

Re-trade the price (the most direct fix, a lower loan means lower debt service and a better DSCR); increase the buyer equity injection (less debt); lengthen the amortization term where possible (lower monthly payment); put more of the seller note on standby (defers cash strain); negotiate a lower seller-note rate; or restructure the deal (asset vs stock, or carve out real estate into a separate financeable piece). If none of those gets the DSCR comfortably above 1.0x after a reasonable owner salary, the deal isn’t financeable at that price, and the right move is to walk away rather than over-leverage into a fragile situation.