SBIR Phase I is a feasibility award — typically in the range of $50,000 to $300,000 depending on the agency — that pays you to prove your innovation can work. Phase II is the development award — commonly in the high six figures up to around $2 million — that pays you to build and demonstrate it. Reviewers judge the two phases by different standards: Phase I sells a credible scientific question and team, while Phase II sells demonstrated feasibility plus a convincing path to a product that someone will buy. Founders who treat Phase II as "Phase I with a bigger budget" are the ones who do not get funded.

The structure: three phases, two of them funded

  • Phase I — feasibility. Usually six to twelve months. The deliverable is evidence: data showing the core technical approach is viable.
  • Phase II — development. Usually about two years. The deliverable is a working prototype or demonstration at meaningful scale, plus a sharpened commercialization story. Only Phase I awardees can generally apply (some agencies offer Direct-to-Phase-II for teams with prior feasibility data).
  • Phase III — commercialization. No new SBIR money; this is the market itself, follow-on government contracts, or private capital.

Award ceilings, timelines, and topic styles vary meaningfully by agency — NSF and NIH run open-ended scientific topics while DoD issues specific technology solicitations. The mechanics of eligibility, registration, and proposal assembly are covered in our SBIR grant application guide, and if a research-institution partnership is central to your project, check whether STTR fits better than SBIR.

What Phase I reviewers actually look for

  • A real technical question. Phase I funds resolving genuine uncertainty. If your product obviously works and just needs engineering polish, reviewers will say so — and decline.
  • Innovation, not increment. A meaningful advance over the state of the art, stated plainly and honestly positioned against existing approaches.
  • A team that can execute. Reviewers fund people. Relevant technical track record — in-house or through partners — carries enormous weight.
  • A crisp work plan. Specific aims, measurable success criteria, and a budget that maps to the tasks. Vague milestones read as vague thinking.
  • Commercial potential, sketched. At Phase I a credible market hypothesis suffices — but it must exist.

What changes at Phase II

Phase II proposals are won or lost on two exhibits Phase I did not require:

  • Your Phase I results. Reviewers read them as the single best predictor of Phase II execution. Hitting your stated Phase I milestones — and saying honestly what did not work and how you adapted — matters more than glossy claims.
  • A serious commercialization plan. Market size with defensible logic, customer discovery evidence, competitive positioning, IP strategy, a revenue model, and ideally third-party validation: letters from potential customers, a strategic partner, or matching private investment. Several agencies explicitly reward private-sector match commitments.

Phase II money is prototype money: it typically carries a project through engineering development, working prototypes, and testing — activities that parallel the commercial prototype development path, with government reporting attached. For medical technologies, Phase II is also where regulatory strategy gets real — reviewers expect an articulated FDA pathway for a medical device.

Positioning for Phase II starts on day one of Phase I

  • Write Phase I aims whose success criteria naturally become the Phase II justification.
  • Start customer discovery during Phase I — reviewers can tell the difference between conversations you had and market reports you bought.
  • Document everything; Phase II proposals quote Phase I data constantly.
  • Budget realistic time for the Phase II proposal itself — it is substantially longer and competes against every strong Phase I graduate in your cohort.

SBIR in your broader funding stack

SBIR's superpower is that it is non-dilutive — you keep every share of your company — and a Phase II award is a strong credibility signal to private investors. Many hardware and deep-tech startups deliberately sequence SBIR alongside equity rounds, a strategy discussed in the startup fundraising pillar. And SBIR is not the only public money available: the government funding pillar and our roundup of grants for inventors map the wider landscape of federal, state, and private sources.

Turn grant money into a working product

Winning the award is half the job; delivering the prototype and data the grant promised is the other half. Projects House provides the engineering execution behind grant-funded development — feasibility studies, prototypes, and test results that satisfy both reviewers and future customers. Tell us about your project through the contact form and we will help you plan development that matches your funding phase.