AARRR (Pirate Metrics) Funnel
Break growth down into five measurable stages so founders know exactly where customers are being lost.
15 min · Dave McClure, 500 Startups
What is this framework?
AARRR splits the customer journey into Acquisition, Activation, Retention, Referral and Revenue. Each stage has its own metric, so instead of asking a vague question like 'is the business growing?', founders can pinpoint exactly which stage is leaking customers and fix that stage specifically.
Dave McClure coined AARRR — nicknamed 'pirate metrics' for its sound — as a simple way for early-stage start-ups to structure their thinking about growth. Rather than staring at a single vanity metric like total sign-ups, founders track five distinct stages, each of which answers a different strategic question.
Acquisition asks how people find you. Activation asks whether they experience your core value quickly enough to stay. Retention asks whether they come back. Referral asks whether they bring others. Revenue asks whether any of this converts to money. Because each stage feeds the next, a business can have excellent acquisition and still fail if activation or retention is broken.
The framework is popular precisely because it forces founders to instrument their business: every stage needs a number attached to it, and every number should have an owner and a target. Without this discipline, teams tend to over-invest in acquisition (which is visible and exciting) while ignoring retention (which is quieter but usually the real growth bottleneck).
What problem does it help solve?
- Diagnose exactly which stage of the customer journey is underperforming
- Avoid vanity metrics by tying each stage to a specific, measurable action
- Prioritise growth experiments where they will have the most impact
- Communicate growth performance clearly to co-founders, mentors or investors
The framework
Each stage narrows the pool of users; the goal is to reduce drop-off between stages, not just fill the top.
Every part explained
Acquisition
How potential customers first discover and arrive at your product.
Ask: Which channels bring people to us, and which bring the most valuable people?
Example: An Instagram Reel showing a five-minute lunch delivery drives app downloads.
Activation
The moment a new user experiences the core value of the product for the first time.
Ask: What is the first meaningful action that shows a user 'gets' the value?
Example: A new user completing their first food order within the app.
Retention
Whether users come back and keep using the product over time.
Ask: Are users returning, and how quickly does usage drop off after the first visit?
Example: Tracking whether a user places a second order within seven days of the first.
Referral
Whether existing users bring in new users through word of mouth or built-in sharing.
Ask: Are our happiest users actively bringing others in, and can we make that easier?
Example: A prompt inviting satisfied customers to invite a friend for a discount on both orders.
Revenue
Whether the activity generated actually converts into sustainable income.
Ask: How much money does each stage of activity actually generate, and is it enough to sustain the business?
Example: A small commission charged on every completed transaction through the platform.
Worked example — CampusEats, a fictional campus food delivery start-up
CampusEats maps its own growth using the AARRR structure to decide where to focus its next quarter of effort.
Acquisition
Instagram Reels showing quick delivery times drive most new app downloads among students.
Activation
A user is considered 'activated' once they complete their first order — currently only 40% of downloads do this.
Retention
Success is defined as placing a second order within seven days; currently around 25% of activated users do so.
Referral
Users are prompted to invite a friend after their second order, with both parties receiving a small discount.
Revenue
CampusEats earns a transaction commission from participating vendors on every completed order.
Diagnosis
The biggest leak is Activation — most students download the app but never complete a first order.
Next step
Simplify the sign-up and first-order flow before spending more on acquisition ads.
Because Activation is the clear bottleneck, CampusEats decides to pause ad spend and fix the first-order flow instead.
How to use it
- 1List every channel through which customers currently discover your product for Acquisition.
- 2Define one specific action that counts as 'Activation' for your product.
- 3Choose a time window (e.g. seven days) and define what a 'retained' user looks like.
- 4Identify or design a mechanism that lets satisfied users refer others.
- 5Attach a monetisation model and measure revenue per stage of the funnel.
- 6Measure the conversion rate between each pair of stages.
- 7Identify the stage with the largest drop-off and prioritise experiments there.
- 8Re-measure after each experiment to confirm whether the bottleneck has moved.
Try it yourself
Define your own AARRR stages for your venture idea, one metric per stage.
Define your funnel
Your work stays on this device. Nothing is uploaded, so use the same browser to come back to it.
When to use it
- Once you have a live product or working prototype generating real user activity
- When growth has stalled and you need to identify which stage is the bottleneck
- When preparing metrics to present to mentors, judges or investors
When not to rely on it
This framework does not prove:
- • It assumes a linear customer journey, which does not fit every business model
- • Early-stage ventures may not have enough data yet to make each stage statistically meaningful
- • It measures behaviour, not the underlying reasons customers behave that way
Common mistakes
- Obsessing over Acquisition numbers while ignoring a leaky Activation or Retention stage
- Defining Activation so loosely (e.g. 'opened the app') that it doesn't reflect real value delivered
- Treating referral incentives as a growth strategy without first confirming retention is healthy
- Not defining a clear time window for retention, making the metric meaningless
Connections
Related frameworks
Quick check
A start-up has strong downloads but very few users complete their first purchase. Which AARRR stage should it focus on first?
Remember this
Growth is not one number — it's five stages, and fixing the wrong one wastes effort. Find the biggest leak before you pour in more at the top.