SBA Resources · Verified against SOP 50 10 8 · Updated July 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 requires an equity injection of at least 10% of total project costs — purchase price plus working capital plus fees, not just the price. A seller note counts only if it's on full standby for the life of the loan (no principal or interest to the seller until your SBA loan is paid off, SBA Form 155) and only up to 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.
Purchase price + working capital + closing/guaranty fees — everything needed to complete the change of ownership.
Seasoned funds — lenders verify the source.
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. And we don't sell your lead.
See the Kit →The seller-note trap (and how to structure around it)
Since the June 2025 SOP, a seller note counts toward your injection only on full standby for the entire loan term — the seller gets nothing, not even interest, until your SBA loan is repaid — and only up to half the required injection. Sellers hate full standby, which is why "the seller will carry 10%" plans collapse in underwriting.
The working structure: your cash covers at least half the injection, a standby note 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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The injection is item 4. Get the full list of what lenders check — documents, ratios, and structure — before you apply.
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Frequently Asked Questions
How much do you have to put down for an SBA loan?
For a complete change of ownership (buying a business), SOP 50 10 8 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. 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. 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.
Is the 10% required on every SBA loan?
No — the 10% floor applies to complete changes of ownership (and startups). It is not a blanket rule on every 7(a) loan. Notably, if an existing business acquires a business in the same industry (same NAICS code), same geographic area, with identical ownership, the SOP treats it as a business expansion and requires no minimum injection at all.