Product management, User experience, Leadership

Sean Ellis Score

A metric used to measure customer satisfaction and loyalty to a product or service.

Also called: Sean Ellis Test and Customer Loyalty Score

See also: Net Promoter Score (NPS), Product Metrics

Relevant metrics: percentage of users who respond 'Very disappointed'

In this article

How to calculate Sean Ellis Score:

Sean Ellis Score = (Number of users who answer 'Very disappointed' / Total number of respondents) * 100

What is Sean Ellis Score?

The Sean Ellis score part of the result from conducting a Sean Ellis Test. At its core, the Sean Ellis Test is a single-question survey designed to gauge how many of your customers consider your product as must-have. The question is: “How would you feel if you could no longer use [product]?”

The responses are:

  1. Very disappointed
  2. Somewhat disappointed
  3. Not disappointed

The goal is to reach a stage where at least 40% of your users would answer “Very disappointed” if they could no longer use your product. This is seen as a strong indicator that your product has achieved product/market fit.

Where did Sean Ellis Score come from?

Sean Ellis, known for coining the term “growth hacking,” developed the Sean Ellis Test, or the “40% rule,” as a simple and practical approach to measure product/market fit. Ellis, who has a rich background in marketing and entrepreneurship, is renowned for his contributions to the rapid growth of companies like Dropbox, LogMeIn, and Eventbrite.

The origin of the Sean Ellis Test lies in Ellis’s work with these and other companies. He observed a common theme across successful companies - a significant portion of their user base viewed the product as a “must-have.” To quantify this observation, Ellis formulated the simple survey question: “How would you feel if you could no longer use [product]?” He proposed that if 40% or more of users responded that they would be “very disappointed,” the product likely achieved product/market fit.

“How would you feel if you could no longer use [product]?”

He introduced this concept to the public in a blog post in 2009, where he explained his methodology and proposed the 40% benchmark based on his experiences. Since then, the test has been widely adopted by startups and established businesses as a straightforward tool to gauge product/market fit.

It’s important to note that while the Sean Ellis Test is a useful tool, it is just one part of understanding your users and building a successful product. It should be used in conjunction with other strategies such as customer feedback, market research, and iterative product development to create a product that truly meets the needs of its users.

Using the Sean Ellis test to identify Product/Market fit?

In the universe of startups, one term echoes from boardrooms to brainstorming sessions: product/market fit. It’s the sweet spot where your product resonates so well with your target market that it nearly sells itself. Sean Ellis, the marketing guru who catapulted Dropbox, LogMeIn, and Eventbrite to success, came up with a simple yet highly effective way to measure this elusive fit. Welcome to your guide to the Sean Ellis Test for Product/Market Fit.

Why use the Sean Ellis Test?

In a world where data is abundant yet often overwhelming, the Sean Ellis Test offers a clear, straightforward metric. It cuts through the noise, offering an unambiguous measure of how much your product matters to your customers. Moreover, it’s easy to implement and interpret, making it a favorite among busy entrepreneurs.

How to Conduct the Sean Ellis Test

The Sean Ellis Test offers a straightforward way to measure product/market fit. It’s easy to conduct, easy to interpret, and can provide invaluable insights. So, whether you’re launching a new product or seeking to improve an existing one, give the Sean Ellis Test a go. After all, understanding your customers is the first step towards creating a product they can’t live without.

  1. Identify your audience. You should survey users who have experienced the core of your product offering. They should have used your product enough to understand its value proposition.
  2. Distribute the survey. Send out the survey to your selected users. This could be done via email, through your app, or any other method that reaches your users effectively.
  3. Analyze the results. Calculate the percentage of users who would be “very disappointed” without your product. If it’s 40% or more, congratulations! According to Ellis, you’ve achieved product/market fit.
  4. Follow-up questions. To gain more insights, it’s recommended to add a few follow-up questions, such as “What type of person do you think would benefit most from [product]?” or “What is the main benefit you receive from [product]?” These answers can guide your marketing and development efforts.

Calculating the Sean Ellis score

The Sean Ellis Test, or the “40% rule” for determining product/market fit, doesn’t involve a complex equation. It’s actually quite straightforward. Here’s how you calculate it:

Distribute a survey to your users asking, “How would you feel if you could no longer use [product]?” with the options being:

  1. Very disappointed
  2. Somewhat disappointed
  3. Not disappointed

Once you have gathered your responses, calculate the percentage of users who answered “Very disappointed”.

The calculation would be:

(Number of users who answer "Very disappointed" / Total number of respondents) * 100

This will give you the Sean Ellis Score. According to Ellis, if this score is 40% or more, your product is likely to have achieved product/market fit.

If the Sean Ellis score is 40% or more, your product is likely to have achieved product/market fit

What if You Don’t Pass the Test?

Don’t be disheartened if less than 40% of your users would be “very disappointed” without your product. This is an opportunity to learn and improve. Look at your follow-up questions, listen to your users’ feedback, and iterate on your product. The path to product/market fit is often paved with learnings from these very insights.

What if my score doesn’t hit the 40% mark?

Sometimes, despite all our hard work and passion, our product may not resonate with the market as we’d hoped. If that’s the case, don’t fret! It’s time for some rethinking and retooling. Remember, in this fast-paced world, it’s not always the strongest or smartest who prevail, but those who can adapt to change the quickest.

But let’s clarify something first: we’re not suggesting you should only create what customers say they want. Rather, the idea is to really understand your target audience’s needs and come up with innovative solutions that hit the mark.

So how do you get into the minds of your customers?

One word: Listen.

Surveys are a great tool to gather valuable feedback about your product. Ask questions that reveal how your product is being used, whether it’s being used as you anticipated, and how paying customers might differ from non-paying users. We have a related article on crafting effective surveys you might find useful.

Even better, you could gain insights through in-depth interviews or focus groups, but bear in mind these methods can be time-consuming and not always cost-effective.

One of the biggest takeaways from market research is this: sometimes when product/market fit seems off, it’s not the product that’s the problem, but the target audience. You might be able to boost your score by making minor tweaks to your product and trying different marketing strategies, rather than undertaking a major product overhaul.

Also, keep in mind that misidentifying customer pain points can throw off product/market fit. It’s essential to understand the scale of the problem your product is addressing - is it a major issue or a minor nuisance? If you’ve misunderstood the problem, you may need to rethink your product or your target audience.

Misidentifying customer pain points can throw off product/market fit.

Finally, don’t forget to track how your product is being used. Understanding what your customers are looking for, where they struggle, where they spend the most time, and their main complaints can give you a roadmap for improvement.

Frequently asked questions

What is a good product-market fit score?

According to Sean Ellis, a good Product/Market Fit (PMF) score is 40% or higher. This score is derived from his survey method, where you ask users, “How would you feel if you could no longer use [product]?”

If at least 40% of respondents answer, “Very disappointed,” it suggests that your product has a strong fit with the market. In other words, a significant portion of your user base considers your product essential, indicating that you’ve achieved product/market fit.

Remember, though, that this is a guideline rather than a hard rule. Depending on your industry, target audience, and other factors, a lower or higher percentage could be acceptable. The key is to aim for continuous improvement, always seeking to increase the percentage of users who find your product indispensable.

How many companies achieve product market fit?

It’s important to note that achieving product/market fit is a significant challenge for many businesses, particularly startups. Many industry experts and venture capitalists, such as Marc Andreessen, consider achieving product/market fit to be one of the most critical milestones for a startup, and one that many fail to reach.

Various reports and studies suggest that a significant number of startups fail due to a lack of product/market fit. For example, CB Insights, a tech market intelligence platform, conducted a post-mortem on 101 failed startups and found that 42% identified the “lack of a market need for their product” as a significant factor in their failure.

Achieving product/market fit requires a deep understanding of your customers, a product that meets a real need, and the ability to communicate that effectively. It’s a process of iteration and learning, and even successful companies may need to revisit and reassess their product/market fit as they scale and as market conditions change.

How long does it take to achieve product market fit?

Ahieving product/market fit is not just about time but also about the process: continuous learning, iterating, and improving.

The timeframe to achieve product/market fit varies widely from company to company. It depends on numerous factors including the complexity of the product, the market it’s serving, the team’s ability to iterate and improve the product, and the receptiveness of customers to provide feedback.

For some startups, it could take a few months to achieve product/market fit, while for others it could take several years. Some businesses may even pivot multiple times before finding a product and a market that fit together.

In the early stages of a startup, the primary focus is often on learning and iteration. Entrepreneurs might build a minimum viable product (MVP), gather user feedback, and then modify their product or even their entire business model based on that feedback. This process might be repeated multiple times, and each cycle could take anywhere from a few weeks to several months.

Once a company has achieved product/market fit, the focus generally shifts to scaling the business. But even at this stage, it’s important for companies to continue listening to their customers and adapting to their needs, as product/market fit isn’t a one-time achievement. Market needs change over time, and what fits today might not fit tomorrow.

What is an example of product-market fit?

Product-market fit occurs when a company’s product satisfies a strong market demand and resonates deeply with its target audience. To better understand, let’s take the example of the ride-hailing service, Uber.

When Uber was launched, it addressed a significant pain point in the market: the need for reliable, on-demand transportation. Traditional taxi services were often seen as unreliable or inconvenient, and public transportation didn’t always provide the flexibility or comfort that people desired.

Uber’s app allowed users to hail a ride with just a few taps on their smartphones, see the price upfront, track their driver’s arrival, and pay automatically via the app. It provided a solution that was more convenient, reliable, and often more affordable than existing options. The strong positive response from customers, rapid growth in users, and expansion into cities around the world indicated that Uber had achieved product-market fit.

Here are some signs that illustrated Uber’s product-market fit:

  1. Customer Satisfaction. Customers were not just using the product but were excited about it, often promoting it to their friends and family. This organic word-of-mouth growth is a strong sign of product-market fit.
  2. High Retention Rates. Users continued to use the service after their first ride, indicating that they found ongoing value in the product.
  3. Market Growth. Uber wasn’t just stealing customers from existing taxi services—it was expanding the market by attracting people who previously didn’t use taxis regularly.
  4. Willingness to Pay. Users were willing to pay for the service, and some were even willing to pay surge prices during high-demand periods, indicating that they saw significant value in the product.

However, it’s crucial to remember that achieving product-market fit doesn’t mean a company can stop innovating or listening to customers. Market needs change over time, and companies need to continuously evolve to maintain product-market fit, as Uber has done by introducing new services like Uber Eats and Uber for Business.

How do you prove product-market fit?

Proving product-market fit involves demonstrating that there’s a significant demand for your product in the market and that your product is meeting the needs of your target audience. Here are some ways you can prove product-market fit:

  1. Customer Surveys. The Sean Ellis Test is a good starting point. If over 40% of your users say they would be “very disappointed” if they could no longer use your product, it’s a strong indicator of product-market fit. Other survey questions could explore customer satisfaction, net promoter score (NPS), and reasons for using your product.
  2. Usage and Retention Metrics. High user engagement and retention rates can signal product-market fit. If users are not only trying your product but also using it regularly over time, it’s a sign they find value in it.
  3. Organic Growth. A strong sign of product-market fit is when new customers are primarily acquired through word-of-mouth or organic channels, suggesting that existing users value the product enough to recommend it to others.
  4. Willingness to Pay. If customers are willing to pay for your product at a price that is sustainable for your business, this is a strong indication of product-market fit. You can gauge this through customer surveys or by testing different pricing strategies.
  5. Market Feedback. Positive reviews, social media mentions, and press coverage can all signal that your product is resonating with your target audience.
  6. Customer Interviews: Conducting in-depth interviews with customers can provide qualitative insights into how well your product is meeting their needs.

Remember that proving product-market fit is not a one-time event but an ongoing process. Market needs and conditions can change, and it’s important to continually check in with your customers and monitor your key metrics to ensure you’re maintaining product-market fit.

Popular tools

The tools below will help you with the Sean Ellis Score play.

  • PMF Survey

    A free tool by Sean Ellis to measure Product-Market fit as defined by the man himself.



Dropbox revolutionized the way we store and share files. Before becoming a household name, they would have needed to ensure that their users found the service valuable. By applying the Sean Ellis Test, they gauged whether users found their service indispensable or whether there was room for improvement. User feedback in this way influenced the development of new features, such as shared folders or Dropbox Paper.


As a provider of remote connectivity services, LogMeIn used the Sean Ellis Test to assess the perceived value of their offering. The feedback obtained helped refine features, improve user experience, and identify key value propositions to be communicated in their marketing efforts.


As an event management and ticketing website, Eventbrite caters to both event organizers and attendees. The Sean Ellis Test was employed separately for these two user groups to measure their respective levels of satisfaction and identify areas for improvement. The feedback influenced the platform’s functionalities like event discovery, ticket purchasing, or event creation.

Relevant questions to ask
  • What is the purpose of using the Sean Ellis Score?
    Hint The Sean Ellis Score is a metric used to measure the success of a product or feature. It is based on the concept of product/market fit, which is the degree to which a product satisfies the needs of a given market.
  • How will the Sean Ellis Score be used to measure success?
    Hint The Sean Ellis Score will be used to measure the success of a product or feature by assessing the degree to which it meets the needs of the target market.
  • What criteria will be used to determine the score?
    Hint The criteria used to determine the score will include customer feedback, usage data, and other metrics that measure customer satisfaction.
  • How will the score be interpreted and used to inform decisions?
    Hint The score will be interpreted and used to inform decisions about product development, marketing, and other areas of the business.
  • What data will be used to calculate the score?
    Hint The data used to calculate the score will include customer feedback, usage data, and other metrics that measure customer satisfaction.
  • How will the score be tracked over time?
    Hint The score will be tracked over time to measure the success of a product or feature and to identify areas for improvement.
  • What are the potential risks associated with using the Sean Ellis Score?
    Hint Potential risks associated with using the Sean Ellis Score include relying too heavily on the score to make decisions, not taking into account other factors that may influence customer satisfaction, and not taking into account changes in the market.

You might also be interested in reading up on:

People who talk about the topic of Sean Ellis Score on Twitter
Relevant books on the topic of Sean Ellis Score
  • Hacking Growth: How Today's Fastest-Growing Companies Drive Breakout Success by Sean Ellis (2018)

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