# ProductMetrics > Every product metric, explained — definitions, formulas, benchmarks, and the major measurement frameworks, written for product managers. Public, read-only, and free to cite. ProductMetrics is a canonical reference for product and growth metrics: 44 metrics organized by the AARRR funnel (Acquisition, Activation, Retention, Revenue, Referral) plus Core Web Vitals, and 4 measurement frameworks (AARRR, HEART, North Star, OKRs). Company-specific claims and benchmark figures carry source citations and a last-reviewed date. No login, no paywall, no tracking wall. A read-only JSON API mirrors every page. ## Metrics - [Daily Active Users (DAU)](https://productmetrics.org/metrics/dau): Unique users who engage with your product in a single day. - [Monthly Active Users (MAU)](https://productmetrics.org/metrics/mau): Unique users who engage with your product at least once in a calendar month. - [Sessions Per User (SPU)](https://productmetrics.org/metrics/spu): How often users return to your product in a given period. - [Conversion Rate](https://productmetrics.org/metrics/conversion): Percentage of users who complete a goal action. - [Feature Adoption Rate (FAR)](https://productmetrics.org/metrics/far): Percentage of eligible users who use a feature. - [Customer Acquisition Cost (CAC)](https://productmetrics.org/metrics/cac): Total cost to acquire a paying customer. - [Growth Accounting](https://productmetrics.org/metrics/growth-accounting): Breaking down user growth into its components. Reveals whether growth is healthy or hollow. - [Activation Rate](https://productmetrics.org/metrics/activation): Percentage of new users who reach a meaningful first milestone. - [Time-to-Value (TTV)](https://productmetrics.org/metrics/ttv): Time from signup to first "aha moment." - [Trial-to-Paid Conversion Rate](https://productmetrics.org/metrics/trial): Percentage of trial users who become paying customers. The moment of truth for your value proposition. - [Product-Qualified Leads (PQLs)](https://productmetrics.org/metrics/pql): Users whose product engagement signals conversion likelihood. Quality over quantity. - [Day 1/7/30 Retention](https://productmetrics.org/metrics/nday): Percentage of users who return on specific days after signup. The clearest early signal of product-market fit. - [Cohort Retention Curves](https://productmetrics.org/metrics/cohort): How retention changes over time for groups of users who joined together. The gold standard for retention analysis. - [Customer Churn Rate](https://productmetrics.org/metrics/churn): Percentage of customers who leave. Critical insight: 5% monthly churn compounds to 46% annual churn. - [Customer Retention Rate (CRR)](https://productmetrics.org/metrics/crr): Percentage of existing customers who stay. - [DAU/MAU Ratio (Stickiness)](https://productmetrics.org/metrics/stickiness): How many days per month users engage with your product. The simplest measure of habit strength. - [Customer Effort Score (CES)](https://productmetrics.org/metrics/ces): How easy it is for customers to get what they need. A better predictor of churn than CSAT. - [Customer Satisfaction Rate (CSAT)](https://productmetrics.org/metrics/csat): Satisfaction with a specific interaction. - [Monthly Recurring Revenue (MRR)](https://productmetrics.org/metrics/mrr): Total predictable monthly revenue from subscriptions. - [Average Revenue Per User (ARPU)](https://productmetrics.org/metrics/arpu): Revenue generated per user over a period. - [Lifetime Value (LTV)](https://productmetrics.org/metrics/ltv): Total projected revenue from a customer over their entire relationship. - [Net Revenue Retention (NRR)](https://productmetrics.org/metrics/nrr): Revenue retained from existing customers, including expansion and churn. The single best predictor of sustainable growth. - [LTV:CAC Ratio](https://productmetrics.org/metrics/ltvcac): Return on acquisition investment. The fundamental unit economics equation. - [CAC Payback Period](https://productmetrics.org/metrics/payback): Months to recover customer acquisition costs. Determines how fast you can reinvest in growth. - [Quick Ratio (SaaS)](https://productmetrics.org/metrics/quickratio): Revenue growth efficiency: how much you gain versus lose. The health check for scaling. - [Rule of 40](https://productmetrics.org/metrics/rule-of-40): A SaaS health heuristic: a company’s revenue growth rate plus its profit margin should add up to at least 40%. - [Gross Margin](https://productmetrics.org/metrics/gross-margin): The share of revenue left after the direct cost of delivering your product. The ceiling on how profitable the business can ever be. - [Net Promoter Score (NPS)](https://productmetrics.org/metrics/nps): How likely customers are to recommend you. - [Product-Market Fit Score](https://productmetrics.org/metrics/pmf): How disappointed users would be without your product. The earliest reliable signal of PMF. - [Viral Coefficient (K-factor) (K)](https://productmetrics.org/metrics/k-factor): How many new users each existing user generates through invitations. The core measure of organic, self-propelled growth. - [Scroll Depth](https://productmetrics.org/metrics/scroll-depth): How far users scroll down a page, measured as a percentage of total page height. - [Form Abandonment Rate](https://productmetrics.org/metrics/form-abandonment): The percentage of users who start filling out a form but leave without submitting it. - [Frustration Score](https://productmetrics.org/metrics/frustration-score): A composite score measuring user frustration signals during a session, derived from rage clicks, dead clicks, error encounters, and navigation reversals. - [Rage Click Rate](https://productmetrics.org/metrics/rage-click-rate): The percentage of sessions containing rage clicks—rapid, repeated clicks on the same element, indicating user frustration with unresponsive or misleading UI. - [Bounce Rate](https://productmetrics.org/metrics/bounce-rate): Percentage of sessions where the visitor views one page and leaves without further interaction. - [Average Session Duration](https://productmetrics.org/metrics/avg-session-duration): The average length of a user session, from first interaction to last, across all sessions in a given period. - [Session Score](https://productmetrics.org/metrics/session-score): A composite 0–100 score measuring whether sessions are deep and engaged or shallow and bouncy, derived from bounce rate, average duration, pages per session, and session-level frustration. - [Navigation Score](https://productmetrics.org/metrics/navigation-score): A composite 0–100 score measuring whether visitors move through a site cleanly, derived from drop-off rates at key pages, session-loop frequency, and the share of single-page sessions. - [Engagement Score](https://productmetrics.org/metrics/engagement-score): A composite 0–100 score measuring depth and return frequency of visitor engagement, derived from median session duration, bounce rate, return-visit rate, and the share of low-engagement sessions. - [Largest Contentful Paint (LCP)](https://productmetrics.org/metrics/lcp): How long until the largest content element in the viewport finishes rendering — the moment a page visually looks loaded to a visitor. - [Interaction to Next Paint (INP)](https://productmetrics.org/metrics/inp): How long the page takes to visually respond after a user interacts — the latency between a tap, click, or keypress and the next frame the browser paints. - [Cumulative Layout Shift (CLS)](https://productmetrics.org/metrics/cls): How much the page visually jumps while it loads — a unitless score for unexpected movement of content the user can already see. - [First Contentful Paint (FCP)](https://productmetrics.org/metrics/fcp): How long until the browser renders the first piece of content — any text, image, or non-blank pixel — after a visitor requests the page. - [Time to First Byte (TTFB)](https://productmetrics.org/metrics/ttfb): How long from the start of the request until the browser receives the first byte of the response — the server-and-network portion of load time, before any rendering begins. ## Frameworks - [AARRR (Pirate Metrics)](https://productmetrics.org/frameworks/aarrr): Maps the full user journey from first touch to advocacy. - [HEART](https://productmetrics.org/frameworks/heart): Measures user experience quality across five dimensions. - [North Star Metric](https://productmetrics.org/frameworks/north-star): One metric that captures core customer value. - [OKRs (Objectives & Key Results)](https://productmetrics.org/frameworks/okrs): Goal-setting framework that connects aspirational objectives to measurable results. ## API (read-only JSON, open CORS) - [All metrics](https://productmetrics.org/api/metrics): Every metric with its full detail fields. - [Single metric](https://productmetrics.org/api/metrics/{slug}): One metric by slug, e.g. https://productmetrics.org/api/metrics/dau - [All frameworks](https://productmetrics.org/api/frameworks): Every framework. - [Single framework](https://productmetrics.org/api/frameworks/{slug}): One framework by slug, e.g. https://productmetrics.org/api/frameworks/aarrr ## More - [Full corpus, inlined](https://productmetrics.org/llms-full.txt): Every metric and framework as plain text in one file. - [OpenAPI spec](https://productmetrics.org/api/openapi.json): Machine-readable OpenAPI 3.1 description of the API. - [API & data overview](https://productmetrics.org/api): Endpoints, response shape, and citation guidance. - [Strategy guide](https://productmetrics.org/strategy): Long-form guide to choosing and using product metrics.