About this programme
Carbon13 describes itself as "the venture builder for the climate emergency": it recruits and funds founders to build startups that can each reduce or remove at least 10 million tonnes of CO2e per year once at scale, then invests directly through its own SEIS fund. It runs two distinct programmes under one brand — the Venture Builder, which forms brand-new companies from individual applicants who arrive without a co-founder or an idea, and the Venture Accelerator, which works with existing pre-seed startups that already have a founding team and are preparing to raise their first round.
The Venture Builder runs as an eight-month cohort in two locations: Cambridge (UK and international applicants) and Berlin (EU-resident applicants, run alongside the DACH climate tech ecosystem). Around 80 individuals join each Cambridge cohort, and are matched into co-founding teams during the programme rather than arriving with one already formed.
The Venture Accelerator is a separate, shorter track for startups that already have two or more founders, UK or EU registration, and are targeting a €1–3 million raise within 12 months — typically early-stage software or deeptech/science-based ventures (TRL 6–7 preferred) addressing climate, water, biodiversity, or resilience.
Both tracks sit inside a wider Carbon13 ecosystem: 400+ Domain Experts, a cohort of Entrepreneurs-in-Residence, and corporate/investor partners, with Carbon13 itself investing pre-seed capital in the ventures it selects rather than acting purely as a mentoring programme.
How it works
Venture Builder — Phase 1, Teaming (Cambridge: 10 weeks; Berlin: 6 weeks): individual applicants seek out a co-founder and a carbon problem to work on. Attendance is partly in-person and mandatory on designated days; participants who have not formed a 2–3 person team by the end of Phase 1 leave the programme.
Venture Builder — Phase 2, Validation (3 months): teams build proof points around their customers, problem, and value proposition, testing feasibility, desirability and viability. At the end of Phase 2, eligible teams pitch to Carbon13's Investment Committee.
Venture Builder — investment: teams whose pitch is approved receive an equity investment from the Carbon13 SEIS Fund. Carbon13's own pages currently disagree on the amount — the venture-builder-faqs page states a £150,000/€150,000 investment of which £60,000/€60,000 is returned to Carbon13 to cover part of Phase 3's costs, leaving a net £90,000/€90,000, while the Venture Builder Cambridge programme page states a flat £120,000 to ventures progressing to Phase 3, with no return payment or equity percentage disclosed. Neither page states the equity percentage taken. Confirm the figure attached to your specific cohort directly with Carbon13 before applying.
Venture Builder — Phase 3, Acceleration (3 months): only teams that received investment continue. Carbon13 becomes a business partner and works alongside its network of Entrepreneurs-in-Residence, corporate and investor partners, and Domain Experts to build customer traction and prepare the venture for its next funding round.
Venture Accelerator — Phase 1: a remote sprint (Carbon13's page describes roughly 7 weeks) of structured one-on-one sessions with an Entrepreneur-in-Residence, working on product/market fit, go-to-market, and investment readiness. Phase 1 participants grant Carbon13 a 1% equity option as part of joining.
Venture Accelerator — Phase 2: a further growth phase (Carbon13's page states 12 months) combining remote support with in-person pitch opportunities, culminating in a pitch at Carbon13's Climate Innovation Showcase.
Venture Accelerator — investment: Carbon13 offers a pre-seed investment of €150,000–€250,000 via a SAFE, targeting a 4–7% equity stake, with potential follow-on funding for ventures that continue to perform.
Who can apply
Venture Builder: open to individuals, not existing companies. You do not need a co-founder, a business idea, or prior experience to apply — Carbon13 says it assesses honesty about experience level rather than requiring a track record, and actively encourages applicants from non-traditional entrepreneurial backgrounds. Technical founders (software, data, ML) can apply without an idea; those coming from physical or natural sciences typically need at least a domain focus.
You can apply already knowing a prospective co-founder, but at least two of you must each submit an individual application and reference each other in your applications. Ventures that already have external investment are welcome to apply, but Carbon13 says they may be better suited to its separate Venture Launchpad programme.
Cambridge cohort applicants do not need to be based in Cambridge or the UK to apply, but must be able to attend the mandatory in-person component of Phase 1. Berlin cohort applicants are expected to be EU-resident. Carbon13 provides support with UK visa applications (including participation in Tech Nation's Global Talent Visa fast-track) for those who need to relocate.
Venture Accelerator: open to startups (not solo founders) with two or more founders already in place, registered in the UK or EU, targeting a €1–3 million raise within roughly 12 months. Carbon13's stated focus is early-stage software or deeptech/science-based ventures at TRL 6–7 addressing climate, water, biodiversity or resilience challenges.
For both programmes, Carbon13 is explicit that building the venture is a full-time commitment: it expects full engagement for the majority of the programme, which in practice means stepping away from other employment.
How to apply
- Venture Builder: complete a brief eligibility questionnaire, then a longer (roughly two-hour) application form via SurveyMonkey Apply at apply.carbonthirteen.com.
- Applications are independently assessed by two Carbon13 team members against a scoring matrix.
- Shortlisted applicants are interviewed by two Carbon13 staff members.
- Successful applicants are offered a place in the next Cambridge or Berlin cohort; check the live programme page for the current application window, as Carbon13 runs a limited number of cohorts per year and deadlines change between them.
- Venture Accelerator: submit a written application with a short (roughly two-minute) video.
- Shortlisted founders go through two interviews with the Carbon13 team.
- Selected ventures go through due diligence before the investment and Phase 1 sprint begin; applications are handled on a rolling basis, so Carbon13 recommends applying early rather than waiting for a stated deadline.
Documents you’ll typically need
- Venture Builder application form (SurveyMonkey Apply)
- Co-founder reference/cross-reference in the individual applications, if applying alongside a known prospective co-founder
- Venture Accelerator written application form plus a short introductory video
- Standard due-diligence materials requested of Venture Accelerator applicants ahead of investment (Carbon13 does not publish an itemised list)
Frequently asked
Do I need a co-founder or an idea to apply to the Carbon13 Venture Builder?
No. Carbon13 accepts individual applicants without a co-founder or an idea for the Venture Builder — team formation and idea development happen during Phase 1 itself. If you have not found a co-founder by the end of Phase 1, though, you have to leave the programme, so it's a hard requirement to clear, just not one you need to arrive with.
How much does Carbon13 invest, and in exchange for what?
For the Venture Builder, Carbon13's own pages currently disagree: the venture-builder-faqs page states a £150,000 (or €150,000 in Berlin) equity investment from its SEIS Fund for teams that clear the Investment Committee pitch at the end of Phase 2, of which £60,000/€60,000 is returned to Carbon13 to cover part of Phase 3's costs, leaving the venture a net £90,000/€90,000 — while the Venture Builder Cambridge programme page states a flat £120,000 with no return payment mentioned. Neither page discloses the equity percentage taken. Confirm the terms directly with Carbon13 before applying. For the Venture Accelerator, Carbon13 offers a €150,000–€250,000 pre-seed investment via SAFE targeting 4–7% equity, plus a 1% equity option granted by Phase 1 participants.
What's the difference between the Venture Builder and the Venture Accelerator?
The Venture Builder starts with individuals who have no company yet — Carbon13 matches you with a co-founder and helps you find and validate a venture idea over an eight-month programme. The Venture Accelerator starts with an existing pre-seed startup that already has two or more founders and is preparing to raise its first external round; it's a shorter, more advisory programme focused on product/market fit, go-to-market, and investment readiness rather than company formation.
Do I need to relocate to Cambridge or Berlin?
For the Venture Builder, yes for Phase 1: attendance on designated in-person days is mandatory (Cambridge runs 9am–5pm UK time; Berlin runs 9:30am–3:30pm Berlin time), though teams can work remotely after the first six weeks if they choose. The Venture Accelerator's Phase 1 is described as a remote sprint, with in-person pitch opportunities during Phase 2.
What impact does my venture need to be able to make?
Carbon13 asks every founder to commit to building a venture capable of reducing or removing net 10 million tonnes of CO2e per year once at scale, addressing CO2e-emitting or decarbonisation-relevant sectors more broadly.
What happens if my venture doesn't get invested by the Investment Committee?
You remain part of the Carbon13 alumni community and can reapply to a future cohort. Carbon13 frames this as a lifelong relationship rather than a one-shot outcome, and says it continues supporting alumni through its network even without a follow-on investment.
Will Carbon13 help with a UK visa if I need to relocate?
Carbon13 says it provides official invitation letters and takes part in Tech Nation's fast-track process for the Global Talent Visa, with decisions typically expected within two weeks of a fast-track application. A standard visitor visa is enough for the Phase 1 in-person component; longer stays require a different visa route (Global Talent, Start-up, or Innovator).
Who owns the IP created during the Venture Builder?
Carbon13 states that the company you form during the programme owns any intellectual property created during it — IP does not sit with Carbon13 or with individual founders personally.
Reviewed 2026-08-16. Programmes change — confirm current eligibility, amounts and deadlines on the official page before you apply. CapEasy is a private consultancy and is not affiliated with any government authority.