IFB — Invitation for Bid
Also known as: IFB, sealed bid, invitation to bid
What It Is
An Invitation for Bid (IFB) is the solicitation for sealed bidding under FAR Part 14. Sealed bidding is used when the requirement can be clearly and completely described, award will be made on price and price-related factors alone, there is no need for discussions, and there is a reasonable expectation of receiving more than one sealed bid. Bidders submit sealed bids by a deadline; the bids are opened publicly at a set time and place; and award goes to the lowest responsive, responsible bidder. There are no discussions or negotiations — a bid either conforms to the IFB (responsive) or it doesn't, and a bidder is either capable of performing (responsible) or not. IFBs are common in construction and well-defined supply buys, and are typically issued on SF 33 or, for construction, SF 1442.
When You See It
- On well-defined requirements — especially construction and standardized supplies — where price is the deciding factor.
- When the agency expects competitive sealed bids and has no need to discuss or negotiate technical approaches.
- On SAM.gov under the 'Solicitation' notice type, with a fixed public bid-opening date and time.
Key Features
| Feature | What It Means |
|---|---|
| Sealed bidding (FAR Part 14) | Used when the requirement is clearly definable, award is on price alone, discussions aren't needed, and multiple bids are expected. |
| Lowest responsive, responsible bidder wins | Award goes to the bidder whose conforming (responsive) bid is lowest and who is capable of performing (responsible) — no best-value tradeoff. |
| Public bid opening | Bids are opened publicly at the stated time and place, and prices are read aloud — transparency is a defining feature of sealed bidding. |
| No discussions or negotiations | Unlike an RFP, there is no competitive range, no discussions, and no proposal revisions — your bid as submitted is it. |
What It Means for an SDVOSB
On an SDVOSB set-aside IFB, the math is brutally simple: be responsive and be the lowest responsible bidder. Because there is no technical evaluation or discussions to recover from, accuracy is everything — a single missing acknowledgment of an amendment, a missing bid bond on construction, or an arithmetic error can make your bid non-responsive and unawardable no matter how good your price. Sharpen your estimating, confirm bonding capacity early on construction IFBs (often issued on SF 1442), and double-check that you have acknowledged every amendment before the public opening. The limitations on subcontracting still apply, so build your subcontracting plan into your price.
How to Respond
- Bid exactly to the IFB — any deviation can make your bid non-responsive and ineligible for award.
- Acknowledge every amendment (SF 30) before bid opening; an unacknowledged material amendment can disqualify your bid.
- On construction IFBs (SF 1442), confirm bid/performance/payment bonding capacity early.
- Submit your sealed bid before the deadline — late bids are almost never accepted, and bid opening is public and final.
Common Pitfalls
- Submitting a bid that deviates from the IFB and is rejected as non-responsive — there are no discussions to fix it.
- Failing to acknowledge a material amendment before bid opening, rendering the bid non-responsive.
- Underestimating on a fixed price you cannot later negotiate — the bid you open with is the price you perform at.
Run the Numbers
Frequently Asked
What is the difference between an IFB and an RFP?
An IFB (Invitation for Bid) uses sealed bidding under FAR Part 14: award goes to the lowest responsive, responsible bidder on price alone, bids are opened publicly, and there are no discussions or negotiations. An RFP (Request for Proposal) uses negotiated procurement under FAR Subpart 15.2: award is based on best value or LPTA across multiple evaluation factors, and the government may hold discussions and request proposal revisions. Use of an IFB requires a clearly definable requirement where price is the deciding factor.
What makes a bid 'non-responsive' on an IFB?
A bid is non-responsive when it does not conform to the material terms of the Invitation for Bid — for example, taking exception to specifications, failing to acknowledge a material amendment, omitting a required bid guarantee on construction, or qualifying the bid. Because sealed bidding allows no discussions, a non-responsive bid generally cannot be corrected and must be rejected, even if it is the lowest price. Responsiveness is judged as of bid opening, so accuracy before you submit is critical.
Primary Sources
Plain-English reference, not legal advice. How a notice or solicitation is structured, and which procedures apply, is set by the specific posting, and the FAR is periodically amended — always read the actual notice and solicitation in SAM.gov and confirm its terms with the contracting officer before relying on this.
Change log (1)
- LaunchedPublished the federal solicitation & notice types reference covering the notice and solicitation types an SDVOSB encounters on SAM.gov — the Sources Sought notice, RFI, presolicitation and special notices, the Request for Proposal (RFP), Request for Quotation (RFQ), Invitation for Bid (IFB), the combined synopsis/solicitation, the Broad Agency Announcement, the sole-source Justification, and the award notice — each with a key-features table, a how-to-respond checklist, common pitfalls, an SDVOSB-specific angle, FAQPage, Article, Dataset, and BreadcrumbList structured data, primary-source FAR citations, and cross-links into the glossary, forms reference, clauses, contract types, how-to guides, FAQ, and the set-aside eligibility, win-probability, and price-to-win calculators.