SBA Resources · Verified against SOP 50 10 8.1 · Updated October 2026
SBA Down Payment (Equity Injection) Calculator
The SBA's floor is 10% of total project costs, and the rules about what counts toward it decide more deals than the percentage does. Structure yours before the lender does it for you.
For a business acquisition, SOP 50 10 8.1 (effective Oct 1, 2026) requires an equity injection of at least 10% of total project costs, purchase price plus working capital plus fees, not just the price, and on a first-time purchase it cannot be waived. A seller note counts only if it's on full standby for the life of the loan (no principal or interest payments to the seller until your SBA loan is paid off, SBA Form 155). The standby note and any minority investor money (under 20%, no control) together count for at most half of the required injection. Cash, gifts, and retirement rollovers (ROBS) count; a seller note with payments counts zero.
Written by Thomas Hartwell, author of the FUNDED series of industry-specific SBA lending guides.
Structure Your Injection
Enter the deal and your sources. The calculator applies the SOP counting rules and shows your gap, if any.
Benchmark: On a $750,000 business acquisition, the SBA's minimum equity injection is $75,000 (10% of total project cost); on $1,000,000 it is $100,000. A seller note on full standby and minority investor money can cover at most half of that, combined. Source: SBA SOP 50 10 8.1 (effective Oct 1, 2026), Appendix 15.
Purchase price + working capital + closing/guaranty fees, everything needed to complete the change of ownership.
Seasoned funds, lenders verify the source.
An outside investor taking under 20% with no control. Counts, but it shares the "no more than half" limit with the seller note, and they can't take distributions except for taxes until the SBA loan is paid off.
The injection is one gate. The kit runs all of them.
The "Will the SBA Fund This Deal?" kit checks your whole deal the way an underwriter will walk-away price, equity injection, collateral adequacy, global DSCR, and the red flags that kill applications verified against the current SOP 50 10 8.1.
See the Kit →The seller-note trap (and how to structure around it)
Under SOP 50 10 8.1 (effective Oct 1, 2026), a seller note counts toward your injection only on full standby for the entire loan term, the seller gets no payments, not even interest (it can accrue), until your SBA loan is repaid, and only up to half the required injection. That half is shared with any minority investor money, so a note and an investor can't each cover half. Sellers hate full standby, which is why "the seller will carry 10%" plans collapse in underwriting.
The working structure: your own unborrowed money covers at least half the injection, a standby note (plus any minority investor money) covers at most the other half, and any additional seller financing above the injection is negotiated as a normal (non-standby) note the lender approves separately. Run the numbers above before you put a structure in the LOI.
Why "10% of the purchase price" is the wrong math
The 10% applies to total project costs, purchase price plus working capital plus fees. On a $900k purchase with $70k working capital and $30k of fees, the injection is 10% of $1,000,000 = $100,000, not $90,000. Underestimating the base is one of the most common reasons buyers show up short.
Lenders also verify that cash is seasoned, sitting in your accounts with a documented source, so money that appears two weeks before closing gets questioned, whatever its size.
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Frequently Asked Questions
How much do you have to put down for an SBA loan?
For buying a business, SOP 50 10 8.1 (effective Oct 1, 2026) requires an equity injection of at least 10% of total project costs, that's everything required to complete the purchase (price, working capital, fees), not just the purchase price, excluding lines of credit and any companion 504 loan. On a first-time purchase (an Initial Acquisition) the 10% cannot be reduced or waived. Individual lenders can and often do require more than the 10% floor on weaker deals.
Does a seller note count toward the SBA down payment?
Only under two strict conditions: the seller note must be on full standby for the entire life of the SBA loan, meaning the seller receives no principal and no interest payments until your 7(a) loan is paid off (documented on SBA Form 155), and it can count for at most half of the required injection. Under SOP 50 10 8.1 that half is shared: the standby seller note and any minority investor money (an outside investor taking under 20% with no control) together count for no more than half. A seller note with regular payments counts zero toward your injection, no matter its size.
Can I use gifted money or my 401(k) for the injection?
Yes. Gifts count (lenders will document the source and that it isn't a disguised loan), and retirement funds can be injected via a Rollover as Business Startups (ROBS) structure, which has its own setup requirements and costs. All cash needs to be seasoned, lenders verify where it's been sitting, typically over the last two bank statements.
Can the 10% ever be reduced or waived?
Not on a first-time purchase. SOP 50 10 8.1 (Appendix 15) says the 10% for an Initial Acquisition, which covers any buyer who becomes the new majority or largest owner without already being an owner or a 24-month employee of the business, cannot be reduced or eliminated. The lender may reduce or waive it only for a Business Expansion (you already own a business that has operated at least two full fiscal years and it buys 100% of another business in the same four-digit NAICS industry group) or an Owner Buyout among existing owners, and only if the buyer shows enough liquidity and no negative net worth at the last fiscal year end. Start-ups also carry a 10% minimum. The old SOP 50 10 8 exemption for same-NAICS expansions with identical ownership is gone.
The rest of the free SBA deal tools
All free, no email required to run them, and every rule is verified against SBA SOP 50 10 8.1 (effective Oct 1, 2026).
SBA Loan Payment Calculator
Monthly and annual payment on a fully amortizing 7(a) loan.
Global DSCR Calculator
Business plus household cash flow against the SBA's 1:1 global floor, next to the 1.25x business coverage floor on a purchase.
Collateral Adequacy Calculator
Are you fully secured, and is your house in play?
Guaranty Fee Calculator
The FY2027 upfront fee on your loan amount.
Max Purchase Price Calculator
The highest price the cash flow will actually finance.
See the 2026 SBA acquisition-financing benchmarks (the numbers behind every calculator above), or put any of these calculators on your own site free .
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GOING DEEPER
Which of your money will the SBA actually count?
The calculator above gives you the number. The Down Payment Structurer runs it on your actual deal, for your industry, and tells you what to do about the answer. Six inputs, already filled in, verdict at the top.
See the Down Payment Structurer, $9Or browse all the tools. The calculators stay free.