Product Market Fit (PMF) is the moment your product satisfies a strong market demand — when users stick, refer others, and pay willingly. Most founders chase PMF on instinct. The best founders measure it.
Marc Andreessen famously said you can always feel PMF: customers buy as fast as you can make it, usage grows, and the press calls. But by the time you 'feel' it, you're late. Measuring leading indicators — retention curves, organic referral, and the Sean Ellis 40% test — gives you a real signal months earlier.
At ProductBlaze, we score PMF on three dimensions: retention strength (do users come back week over week?), engagement depth (do they use the core action repeatedly?), and qualitative pull (would they be 'very disappointed' without it?). A composite score above 70 means you're in PMF territory.
If you're below 50, don't add features. Talk to users, narrow your ICP, and sharpen the core value prop. PMF comes from subtraction more often than addition.