Accelerators and incubators both promise to help an early company grow, and the words are often swapped. The difference shows up in the deal: how long you stay, whether money changes hands, what you give in return and how the programme ends. This guide sets out the usual shape of each, the questions that tell them apart whatever a programme calls itself, and how to choose.
What an accelerator is
The most cited academic description comes from Yael Hochberg, writing for the National Bureau of Economic Research in 2016. She describes seed accelerators as fixed-term, cohort-based “boot camps” for startups that end in a public pitch event, the demo day, where the cohort pitches to investors. Three features follow from that.
- A cohort. Companies are chosen together, start on the same day and move through the programme as a group.
- A clock. The programme has a fixed end date, and the work is compressed to fit it.
- A finish line. The demo day puts every company in front of investors at once. Our guide to what a demo day is covers how that works.
Most accelerators also invest a small, standard amount in exchange for equity. Y Combinator’s about page, read on 18 October 2026, describes a three-month programme run four times a year that invests US$500,000 in each company. Techstars describes its accelerators as three months of mentorship-driven support. The listings for Y Combinator and Techstars show the published terms in full.
Inside the programme, the weeks are structured: regular check-ins with the people running it, mentors matched to the company, workshops on fundraising and sales, and a lot of pressure to show progress by demo day. The cohort itself is part of the value, because founders compare notes and introduce each other to customers and investors.
Because accelerators run in cohorts, they also run on deadlines. Applications open and close on set dates, often months before the programme starts, and missing one can mean waiting for the next cohort. The deadlines page lists every window closing in the next 90 days.
What an incubator is
There is no single definition that every incubator would sign up to. One US federal statute gives a useful starting point. The definitions section of the Native American Business Incubators Program law, passed in 2020, describes a business incubator as an organisation that provides physical workspace and facilities to startups, and is designed to speed their growth through access to capital, education, counselling, networking and mentorship. That law covers one federal programme, but the description fits incubators generally.
Notice what it leaves out. Nothing about a fixed term, a cohort or an investment. That is typical of incubators:
- They often take companies earlier, sometimes before there is a product or a full team.
- Companies stay for as long as the support is useful, often a year or more, and leave when they outgrow it.
- They are frequently run by universities, cities, non-profits or property operators, and are paid for by rent, membership or a sponsor rather than by taking equity.
- Many are built around a place: desks, labs, workshops and shared equipment.
The support is usually practical rather than scheduled: introductions to advisers and investors, help with legal and accounting basics, events, and a community of other early companies in the same building. Costs vary widely and many incubators do not publish them. BioLabs, for example, bills membership per person plus a charge per lab bench, and does not publish its prices.
Some examples from our listings: Greentown Labs gives climate startups labs and prototyping space, LabCentral rents shared lab space to early life-science companies, and Harvard Innovation Labs runs a self-paced incubator for Harvard student ventures. The incubators section lists every one we track.
How to tell them apart
The labels are a poor guide. Some programmes called incubators invest for equity, and some accelerators take none: German Accelerator and Next 36 both say they take no equity. Look at the terms instead.
| Question | Usual accelerator answer | Usual incubator answer |
|---|---|---|
| How long? | A fixed term, often about three months | Open-ended, or a year or more |
| How do I join? | Apply for a cohort before a deadline | Apply at any time, or in periodic rounds |
| Does it invest? | Often, a small standard amount | Usually not; some offer grants |
| What does it cost me? | Equity, sometimes a fee | Rent or membership, or nothing |
| How does it end? | A demo day for investors | When you outgrow it |
Five questions settle most cases, whatever the name:
- Is there a fixed start and end date?
- Does the programme invest, how much, and on what instrument?
- What does it take: equity, a fee, rent, or a share of a future round?
- What will you get that you cannot get alone: investors, customers, space, equipment or credibility?
- Who else is in it, and what did earlier companies go on to do?
Every listing on this site answers the first three from the programme’s own pages, and says “not published” where the programme has not said. The last two need your own research: ask founders who went through the programme what they got from it, and whether they would do it again on the same terms.
Which one fits your company
An accelerator fits when the team can work on the company full-time, you have something to show or can build it quickly, and you plan to raise money soon after the programme ends. You are paying for speed and access with equity, so price it first. The accelerator dilution calculator shows what a stake costs through later rounds, and how startup accelerators work explains the standard deal.
An incubator fits when you are still testing the idea, when you need space or equipment more than money (common in biotech, hardware and climate work), or when you want support without giving up equity this early. If an equity-free cheque is on the table, the equity or equity-free calculator shows the exit value at which the equity would have been the expensive money.
Students and researchers have a third route: programmes run by their own university, which are often free and take no equity. Our guide to university incubators covers who can join and what to check about intellectual property.
If you are unsure which stage you are at, be honest about what is holding the company back. If it is money and investor attention, an accelerator addresses that directly. If it is the product, the science or the team, a longer and cheaper programme may do more.
The choice is rarely final. Many founders start in an incubator or a university programme and apply to an accelerator once the company is ready to raise. Whichever you join first, read its terms for anything that would get in the way of the next step, such as a right of first refusal on your next round or a stake that grows when you raise.
Sources
Each page was read on the date shown. Figures in this guide carry the date the source gives them.
- NBER, Innovation Policy and the Economy, volume 16 (Yael V. Hochberg): Accelerating Entrepreneurs and Ecosystems: The Seed Accelerator Model. Published March 2016. Read 18 October 2026.
- US Government Publishing Office, United States Code, 2023 edition: 25 U.S.C. 5802: Definitions. From Public Law 116-174 of 20 October 2020. Read 18 October 2026.
- Y Combinator: What happens at YC. Undated page. Read 18 October 2026.
- Techstars: Techstars accelerators. Undated page. Read 18 October 2026.