How do you measure product-market fit?

It's an area that we struggle to teach at universities and entrepreneurship centres. Getting idea validation data is a more mature science now but very little work has been put into defining product-market fit and measuring it. It probably lies in the words: "Does your product have a large enough customer segment (market) that is buying and using it". But how do you measure this? You posted a good question. I'm enjoying the answers. Please keep them coming😀.

Retention rate, churn rate, organic growth rate (likes, recommendation, feedback)

Getting a product-market fit is a long journey. It's not binary, you have it or don't. It's all in between as well. Early on: With small number of customers - working as closely with customers as possible, assist with onboarding, processing their feedback, making sure the product not only solves their problem but helps them to succeed. Large volume of customers: Growth Rate, Retention Rate, but also important shrinking Churn Rate. Negative MRR Churn Rate generally means you're doing great. Signs of good product-market fit, growing numbers in: - customer acquisitions (sign ups, but not an indication of PMF alone, only the interest) - customer activation (they become paying customers) - customer success (they achieve results and successfully use the product) - customer retention (they stick around for the estimated life-time or longer)