How Much Money Do You Need to Buy a Small Business?

The short version

• On a $300,000-SDE business bought for $900,000, the SBA down payment is about $90,000, and the debt runs near $125,774 a year.
• Affordability is not whether a lender approves you. It is whether the cash left after you replace the owner covers that debt with room to spare.
• The number that decides it is debt service coverage, and most buyers never run it before they make an offer.
• Below: the down payment, the coverage math, and the living-expense reserve that keeps you solvent in year one.

Most buyers ask whether a lender will approve them. That is the wrong first question.

A lender approves the loan based on the business's last three years. You live with the loan based on what the business throws off after you take over and pay someone to do the work the seller did.

So how much money do you need to buy a business is really one calculation: does the cash flow cover the debt after the owner is replaced, with a reserve left over?

This article runs that calculation on a clean example so you can run it on a real one.

How much money do you need to buy a business: the short answer

You can afford to buy a small business when its cash flow, after you replace the owner's role, covers your annual loan payment by at least 1.25x and still leaves a living-expense reserve. The deciding number is not the price; it is the cash that survives owner replacement and debt service.

That last point is the whole game. Stated profit and spendable cash are not the same thing, and the gap between reported profit and actual cash flow is where most affordability mistakes hide.

The worked calculation on a $300K-SDE business

Take a service business with $300,000 in seller's discretionary earnings, priced at $900,000, financed with an SBA 7(a) loan. Here is the affordability calculation, in order.

1. Down payment: about $90,000. SBA 7(a) acquisition loans typically require 10% equity, so on a $900,000 price that is roughly $90,000 of your own cash. Confirm the exact equity rule against the current SBA 7(a) loan requirements before you budget it.

2. Closing costs on top of the down payment. Lender fees, legal work, and the SBA guarantee fee land on you at close, not the seller. Budget for the closing costs that sit on top of the down payment so the down payment is not your last dollar.

3. Annual debt service: about $125,774. Financing $810,000 over the SBA-standard 120-month term at the FY2025 median 7(a) rate of 9.50% is roughly $10,481 a month, or about $125,774 a year. A different rate changes this, so run your own; 9.50% is the median, used here as the example.

4. Replace the owner before you count the cash. That $300,000 SDE includes the seller's labor. If you must pay a manager $90,000 to do that work, the cash available to service the loan is $210,000, not $300,000.

5. Debt service coverage: 1.67x. Divide the $210,000 of post-replacement cash by the $125,774 of annual debt service. That is a coverage ratio of 1.67, above the 1.25x lenders want and the floor you should want.

6. Living-expense reserve: what is left over. After debt service, about $84,000 remains. That has to cover your salary, a working-capital buffer, and the months when revenue dips, so a reserve of six months of operating expenses sits underneath all of this.

The result: this deal is affordable, with a coverage cushion and cash left to live on. Change the price, the rate, or the manager's salary and the coverage moves first.

Read the cash, not the asking price

The calculation only works if the $300,000 SDE is real. A seller's number is a starting point for verification, not a fact you build a loan around.

Before you trust the SDE, learn to read a small business P&L and find the add-backs that inflate it. An add-back that does not survive diligence is coverage you assumed but never had.

The single most common affordability error is counting the owner's pay as buyer cash. The seller worked 50 hours a week; if you replace that with a manager, the manager's salary comes out before the loan payment, every month.

Why financing is risk structure, not permission

A lender's approval tells you the deal clears their underwriting. It does not tell you the deal is safe for you, and those are different tests.

Financing is risk structure. The down payment, the term, the rate, and the coverage ratio decide how much shock the deal absorbs before it stops paying you.

Affordability has two halves, and most buyers count only the first. The first is cash to close, the down payment plus closing costs plus the reserve. The second is survivability, whether the coverage holds when year one runs short.

Run the calculation at a 20% revenue drop in year one. If coverage falls below 1.25x under that stress, the deal is not affordable at this price, whatever the lender approves.

That is the discipline: affordability is the coverage that holds when the year goes sideways, not the loan you happen to qualify for.

FAQ

How much money do you need to buy a small business?

You need the down payment plus closing costs plus a living-expense reserve, not just the down payment. On a $900,000 SBA-financed deal that is roughly $90,000 of equity, several thousand in closing costs, and a six-month operating reserve that keeps you solvent when year one runs slow.

What debt service coverage ratio do you need to buy a business?

Lenders generally want a debt service coverage ratio of at least 1.25x, meaning the cash flow covers the loan payment 1.25 times over. Calculate it on cash after you replace the owner's role, not the seller's full SDE, because a ratio computed before owner replacement overstates what the business can actually carry.

Does an SBA loan mean I can afford the business?

An SBA approval means the loan clears the lender's underwriting, not that the business is safe for you to own. Affordability is debt service measured against cash flow after owner replacement, with a reserve, so a deal can be approvable and still be too tight to survive a 20% revenue drop in year one.

The calculation above is only as good as the cash flow you put into it, and most buyers never verify the seller's number before they make an offer.

The free Keystone diagnostic gives you three scores and an estimated sale price, calibrated against 10 years of BizBuySell Insight Reports and 1.6M+ SBA 7(a) loan records. You see what the business is really worth before you anchor to an asking price.

Get your three scores and an estimated sale price, free, at app.trykeystone.io.

When you are running the numbers on real deals, Keystone Pro ($199/mo, $1,990/yr) includes the Deal Analyzer, which runs the down payment, debt service, and coverage math on each target so you compare deals on cash, not on price.