SBIR Phase II: How to Write the Proposal That Converts Your Phase I Results

The Phase II Opportunity: Where SBIR Gets Real

Phase I proved your concept was feasible. Phase II is where you build the thing. The jump from a six-to-twelve-month feasibility study to a two-to-three-year, million-dollar-plus development effort is the most consequential transition in the SBIR lifecycle, and the proposal you write to make that transition determines whether your technology dies in the valley of death or reaches a market.

The numbers favor you. Across all federal agencies, roughly 50% to 60% of Phase II proposals receive funding, compared to approximately 17% for Phase I. That ratio makes sense: agencies have already invested in your Phase I work and want to see returns. But the higher success rate does not mean the proposal is easier. Phase II reviewers are more demanding, the technical depth expected is substantially greater, and the commercialization plan must demonstrate real market traction rather than speculative projections.

Every major SBIR agency — the Department of Defense, the National Institutes of Health, the National Science Foundation, the Department of Energy, NASA, USDA, and others — runs its own Phase II program with distinct submission timelines, page limits, evaluation criteria, and budget ceilings. This guide covers the universal strategic principles that apply across all of them, with agency-specific details where they matter most.

For current SBIR opportunities across all agencies, browse SBIR grants on Granted.

Phase II Award Sizes and Duration by Agency

Understanding what you are competing for shapes how you write the proposal. Phase II awards vary significantly by agency, and the budget you request must align with both the agency's guidelines and the realistic cost of the work you propose.

NIH awards Phase II grants (activity code R44) up to approximately $2 million in total costs over a project period of two to three years. Individual Institutes and Centers may set their own caps. The NIH Omnibus solicitation provides current guidelines, and you should confirm the limit with your IC's SBIR program officer before finalizing your budget.

NSF Phase II awards are up to $1.25 million over two years. NSF also offers supplemental funding opportunities — including commercialization supplements and Phase IIB — that can extend total funding well beyond the base award.

DoD Phase II awards vary by service branch and component. The general guideline is approximately $1 million to $1.75 million over a 24-month period, though DARPA, the Missile Defense Agency, and individual service branches may deviate. Always check the specific solicitation instructions for your component.

DOE Phase II awards are typically up to $1.6 million over two years for the Office of Science programs. Applied energy programs may differ.

NASA Phase II awards go up to $850,000 over 24 months, with the option for Phase II-E (Extended) awards that provide additional funding to accelerate commercialization.

USDA Phase II awards are up to $650,000 over two years through the NIFA SBIR program.

The budget you request must be justified line by line. Reviewers at every agency flag proposals where the budget appears disconnected from the scope of work. If you request the maximum and your work plan only plausibly requires 60% of it, you will lose points. If you request well below the ceiling, reviewers may question whether the scope is ambitious enough for Phase II.

Submission Timelines and the Invitation Question

The mechanics of when and how you can submit a Phase II proposal differ by agency, and getting this wrong can cost you an entire funding cycle.

NIH operates on a standard receipt date cycle. Phase II (R44) applications follow the same three-per-year submission schedule as other NIH grants (typically January 5, April 5, and September 5). You do not need an invitation. Any Phase I awardee can submit a Phase II application to the Omnibus solicitation at any receipt date, provided Phase I work is sufficiently advanced to report meaningful results.

NSF requires Phase II proposals to be submitted between 6 and 24 months after your Phase I start date. NSF provides submission instructions directly to Phase I awardees. All proposals go through Research.gov — NSF does not accept Phase II proposals through Grants.gov.

DoD historically required an invitation from the relevant service branch to submit Phase II. That requirement has loosened: all DoD Phase I awardees now have the opportunity to submit Phase II proposals, but the specific mechanism and timeline vary by component. Some branches open a defined submission window; others accept proposals on a rolling basis. Check the DSIP (Defense SBIR/STTR Innovation Portal) for your component's current instructions.

DOE, NASA, and USDA each maintain their own Phase II submission cycles. DOE typically invites Phase I awardees to submit Phase II proposals. NASA opens Phase II windows tied to its solicitation schedule. USDA accepts Phase II applications from Phase I awardees through its standard NIFA process.

The universal rule: begin planning your Phase II proposal no later than the midpoint of your Phase I project. If you wait until Phase I is complete to start drafting, you will either miss submission windows or write a rushed proposal that does not do justice to your results.

How Phase II Review Criteria Differ from Phase I

Phase I reviewers are asking one question: is this concept feasible? Phase II reviewers are asking three: did Phase I work, is the Phase II plan sound, and will this technology reach users?

That shift in emphasis changes what a winning proposal looks like.

Technical Merit Increases in Specificity

Phase I proposals can get away with describing a plausible technical approach supported by preliminary data. Phase II proposals cannot. Reviewers expect a detailed experimental plan, specific milestones with quantitative success criteria, statistical analysis plans where applicable, identification of technical risks with concrete mitigation strategies, and a clear development pathway from the current technology readiness level to a prototype or product that can enter testing with end users.

The technical volume is where your Phase I data earns its return. Every claim about what you will accomplish in Phase II must be grounded in what you demonstrated in Phase I. If your Phase I results showed your sensor achieved 85% accuracy in controlled conditions, your Phase II plan should explain how you will reach the 95% accuracy needed for field deployment, what the engineering challenges are, and why your approach to overcoming them is credible.

Commercialization Moves from Speculative to Concrete

Phase I commercialization plans are largely hypothetical. Reviewers understand that a company at the feasibility stage may not have customers, revenue, or detailed market data. Phase II is different. By the time you submit Phase II, you have been working on this technology for six to eighteen months. Reviewers expect evidence that you have engaged with potential customers, validated market assumptions, and developed a realistic go-to-market strategy.

At NIH, the commercialization plan is a scored review element and is evaluated alongside the scientific merit of the Research Strategy. At DoD, commercialization and transition potential directly influence funding decisions — program managers want to see a path to Phase III procurement. At NSF, the commercialization plan is a separate required document evaluated by its own review panel.

Team and Resources Face Higher Scrutiny

Phase II proposals must demonstrate that you have the team, facilities, and partnerships to execute a multi-year development program. If your Phase I team was a PI and one technician, reviewers will question whether that team can deliver Phase II. Key personnel additions, subcontractor relationships, equipment acquisitions, and facility upgrades should all be addressed explicitly.

Presenting Phase I Results: The Make-or-Break Section

The single most critical element of any Phase II proposal is how you present your Phase I results. Failure to accomplish Phase I objectives is the most common critical flaw identified by SBIR Phase II reviewers, and even successful Phase I projects can be torpedoed by a poorly written progress report.

Structure Around Your Original Aims

Open with the Specific Aims (or technical objectives) from your Phase I proposal, stated verbatim. For each aim, present what you accomplished using quantitative data. Tables and figures are more persuasive than narrative descriptions. If your Phase I proposed three aims, your progress report should address all three — including any that were not fully achieved.

Quantify Everything

Replace vague language with measurable outcomes. Instead of "We successfully demonstrated proof of concept," write "Our prototype achieved a detection limit of 2.3 ng/mL (target: <5 ng/mL), with a coefficient of variation of 8.2% across 150 samples (target: <15%)." Reviewers are scientists and engineers. They want numbers, experimental conditions, sample sizes, and statistical significance.

Address Shortfalls Directly

If you did not fully achieve a Phase I objective, explain why and what you learned. Reviewers respect transparency far more than spin. If an approach did not work as expected, describe what the data told you and how it informed your Phase II design. Adaptive learning — the ability to pivot based on evidence — is viewed positively. Hiding failures or omitting inconvenient results will cost you credibility if reviewers detect it, and they usually do.

Connect Results to Phase II Justification

Every Phase I result should point forward to a specific Phase II activity. If your Phase I data showed that a particular material performed well under certain conditions but degraded under others, your Phase II plan should include durability testing and material optimization as an explicit aim. The progress report and the proposed research plan should read as a continuous narrative, not as two disconnected documents.

Include Supporting Evidence

Publications, conference presentations, patent filings, and letters from potential customers or collaborators that reference Phase I results all strengthen your case. Even if the Phase I work is not yet published, cite manuscripts in preparation or conference abstracts. Intellectual property activity signals commercial intent, which reinforces your commercialization plan.

Writing the Phase II Technical Plan

The technical plan is the largest section of any Phase II proposal and the section where most proposals succeed or fail. Across agencies, the principles are consistent even though formatting requirements differ.

Organize by Specific Aims or Objectives

Structure your technical plan around three to five specific aims (NIH) or technical objectives (DoD, NSF, DOE). Each aim should represent a self-contained work package with defined inputs, activities, milestones, and deliverables. Aims should be parallel where possible so that a setback in one does not block all others.

For each aim, include:

• Rationale: Why this aim matters for the overall project and what Phase I data supports it
• Technical approach: Detailed methodology, experimental design, materials, and procedures
• Success criteria: Quantitative benchmarks that define completion
• Risk assessment: Specific technical risks and contingency plans for each
• Timeline: Realistic scheduling with dependencies identified

Address Scalability and Manufacturing

Phase I was about feasibility. Phase II must address how your technology moves from the lab bench to a form that can be manufactured, deployed, or distributed. Even if full-scale manufacturing is a Phase III activity, reviewers want to see that you have considered design for manufacturability, supply chain constraints, regulatory requirements, and production costs. Proposals that present elegant science but ignore the engineering reality of getting a product to market will score poorly on approach.

Include a Gantt Chart or Milestone Table

Every agency expects a visual project timeline. A well-constructed Gantt chart that maps aims to quarters, shows dependencies between tasks, identifies go/no-go decision points, and indicates when key deliverables will be produced communicates project management competence. Reviewers use it to assess whether your scope is realistic for the proposed budget and duration.

Plan for User Testing

Phase II should include engagement with end users, whether that means clinical validation studies (NIH), field testing with military end users (DoD), beta testing with commercial customers (NSF), or pilot deployments. Proposals that defer all user engagement to Phase III appear disconnected from reality. Even preliminary user feedback data strengthens the proposal significantly.

The Commercialization Plan That Reviewers Actually Fund

The commercialization plan is where technical founders most frequently underperform. A compelling commercialization plan is not a business plan — it is an evidence-based argument that your technology will reach users and generate impact beyond the grant period.

Define the Market with Specificity

Total addressable market figures from industry reports are a starting point, not a destination. Identify your specific target customer segments, quantify the number of potential buyers or users, describe their current alternatives, and explain why your technology is a superior solution. If you have conducted customer discovery interviews, cite them. If you have letters of intent, purchase commitments, or licensing discussions in progress, include them.

Show Traction

Any evidence of commercial engagement is valuable: pilot partnerships, beta users, revenue (even small amounts), memoranda of understanding, expressions of interest from potential acquirers or licensees, or funded Phase III or follow-on contracts. The difference between a Phase I and Phase II commercialization plan is the expectation of traction. You have had six to eighteen months to validate your market assumptions. Reviewers want to see that you used that time.

Describe Your Business Model

How will you make money? Licensing, direct sales, SaaS, per-test pricing, government procurement? Be specific about pricing strategy, margins, sales channels, and the timeline to revenue. If you are pursuing a regulated market (FDA, EPA, FCC), describe the regulatory pathway and its impact on your commercialization timeline.

Address Intellectual Property

Detail your IP strategy: patents filed, patents pending, trade secrets, freedom-to-operate analysis. At DoD, data rights under the SBIR program give the government certain usage rights to SBIR-developed technology. At NIH, IP strategy is evaluated as part of commercial potential. A proposal with no IP strategy raises questions about defensibility and investor interest.

Include Letters of Support

Letters from potential customers, distribution partners, strategic collaborators, investors, or government end users are among the most persuasive elements of a commercialization plan. A letter from a DoD program manager expressing interest in Phase III procurement is worth more than ten pages of market analysis. A letter from a hospital system expressing willingness to participate in clinical validation is worth more than any competitive landscape diagram.

Agency-Specific Tactical Advice

NIH (R44)

The Research Strategy has a 12-page limit. Use the Significance-Innovation-Approach structure. The Phase I Progress Report is a separate required document — do not bury Phase I results inside the Research Strategy. The Commercialization Plan is scored and discussed during study section review. Contact your IC's SBIR program officer before submitting to confirm the budget cap and discuss whether your Phase II scope aligns with IC priorities. If you received a strong Phase I summary statement, reference it (briefly) as validation.

DoD

Technical volume page limits vary by component: 50 pages for the general DoD format, 15 pages for Army white papers, 20 pages for DARPA Direct to Phase II. The Company Commercialization Report (CCR) is pulled from your DSIP profile and counts separately from the technical volume. Transition potential — the likelihood your technology will be acquired by a military customer — carries outsized weight. Include a letter of support from a program of record, acquisition office, or military end-user organization if you can obtain one.

NSF

Phase II proposals go through Research.gov with a specific format: Project Description (up to 15 pages), Phase I Results (1-4 pages), and a separate Commercialization Plan (no page limit, but conciseness is valued). NSF evaluates technical merit and broader impacts. Broader impacts for SBIR means commercial impact, job creation, societal benefit, and technology diffusion. NSF also weighs the strength of the team heavily — if your Phase II requires capabilities your current team lacks, show that you have identified and committed the right people.

DOE

DOE Phase II proposals are typically submitted in response to an invitation following Phase I. The technical plan must address both the scientific merit of the R&D and its relevance to the DOE program office's mission. DOE reviewers care deeply about energy impact — quantify the potential energy savings, emissions reductions, or grid reliability improvements your technology could deliver at scale.

Common Mistakes That Kill Phase II Proposals

Treating Phase II as Phase I with a bigger budget. Phase I was about feasibility. Phase II is about development, prototyping, and market preparation. If your Phase II work plan reads like Phase I objectives with more money, reviewers will question whether you understand the program.

Weak or generic commercialization plan. Stating that the market for your technology is "$X billion" without identifying specific customers, pricing, distribution channels, and competitive differentiation is insufficient for Phase II. This is the most commonly cited weakness across all agencies.

Incomplete Phase I reporting. Failing to address all Phase I objectives, omitting negative results, or providing only qualitative descriptions when quantitative data exists. Reviewers will check your Phase I final report against your Phase II progress narrative. Inconsistencies erode trust.

Overpromising scope. Proposing more work than can plausibly be accomplished within the budget and timeline. Reviewers who have managed R&D programs can estimate level of effort. If your proposal describes five aims, each requiring specialized expertise, expensive equipment, and multi-site coordination, but you request $750,000 and propose to complete everything in 18 months, the proposal will be flagged as unrealistic.

Ignoring administrative requirements. Page limits, formatting specifications, required documents, and submission deadlines are compliance gates. Proposals that exceed page limits or omit required sections are frequently returned without review. This is the most preventable failure mode and it happens at every agency in every cycle.

No contingency planning. Proposals that present only the success path, with no acknowledgment of technical risks and no alternative approaches, signal naivety. Include go/no-go decision points and explain what happens if a key approach does not work.

Frequently Asked Questions

What is the typical Phase I to Phase II conversion rate?

Approximately 50% to 60% of Phase II proposals receive funding across all agencies, making it substantially more competitive than Phase I (roughly 17% success rate). However, this rate varies by agency: DoD components may be higher for invited proposals, while NIH rates depend on study section scores and IC paylines. The minimum Phase I to Phase II transition rate enforced by SBA performance benchmarks is 25% for companies with more than 20 Phase I awards in the past five fiscal years. Companies below this threshold may be excluded from future Phase I competitions.

Can I submit a Phase II proposal if my Phase I results were mixed?

Yes, and you should. Mixed results with honest analysis and a well-adapted Phase II plan can score as well as or better than proposals where everything went perfectly. Reviewers value intellectual honesty and adaptive learning. What kills a proposal is not mixed results — it is hiding unfavorable data or failing to explain how Phase I findings shaped your Phase II approach. If Aim 2 of your Phase I did not meet its target, explain what happened, what you learned, and how your Phase II design accounts for it.

How early should I start writing my Phase II proposal?

Begin drafting at the midpoint of your Phase I project. By then you should have preliminary data, initial customer feedback, and enough experience with the technology to outline a credible Phase II scope. Waiting until Phase I is complete leaves insufficient time for the level of detail Phase II proposals require — particularly the commercialization plan, letters of support, and budget justification. If your agency requires an invitation or opens a specific submission window, back-plan from that date. For NIH, target the receipt date that falls approximately two to four months after your Phase I end date to ensure you have final data while maintaining momentum.

Do I need new letters of support for Phase II?

Phase I letters of support are insufficient for Phase II. Obtain updated letters that specifically reference your Phase I results, your Phase II objectives, and the letter writer's intended role in the Phase II project. Letters from potential customers should describe their interest in the technology based on what you demonstrated in Phase I, not based on what you proposed to do. Letters from collaborators should outline their specific contributions to Phase II and the resources they will commit. Generic letters that could apply to any project add no value and may signal to reviewers that the relationship is not genuine.

What if my company's focus has shifted since Phase I?

Phase II proposals must be a direct continuation of Phase I work. You cannot pivot to an entirely different technology or application and expect Phase II funding for it. However, you can narrow, expand, or redirect your approach based on Phase I findings. If customer discovery during Phase I revealed a more valuable application for your core technology, explain how Phase I data supports this refined direction. The key is demonstrating continuity of the technical work while showing that your commercial strategy has evolved based on evidence. If the shift is substantial, discuss it with your agency program officer before submitting.

Granted helps research teams and small businesses find the right SBIR opportunities and build competitive proposals — from Phase I feasibility through Phase II development.