What Is a Conversion Funnel?

A conversion funnel is the ordered sequence of steps a visitor passes through on the way to a goal — such as visit → signup → activate — where some share of people drop off at every step. The name comes from the shape: wide at the top where everyone enters, narrow at the bottom where only the people who completed the goal come out.

Why "funnel" and not just "conversion rate"

A conversion rate collapses the whole journey into one number: converters ÷ visitors. That tells you how many convert but not where you lose everyone else. A funnel keeps the steps separate, so a single 3% rate becomes a sequence you can actually act on. The value is entirely in the drop-off between steps — the narrowing — because that's the map of where your effort pays off.

A worked example

Take a typical self-serve SaaS funnel over a month:

Step	People	Conversion to next step
Visited landing page	10,000	—
Started signup	1,500	15%
Completed signup	950	63%
Activated (did the core action)	520	55%

Read it as the steps between the rows. The worst drop is the first one: only 15% of visitors even start the signup. That single number tells you where to work — the landing page and its CTA — and tells you not to spend the week polishing the signup form, which already converts a healthy 63%.

This is the whole point of a funnel: it turns "our conversion is low" (unactionable) into "85% of visitors never start signup" (a specific, fixable problem).

A simple taxonomy: top, middle, bottom

Funnel steps group into three stages, which helps you reason about why a drop happens:

1. Top of funnel (awareness) — the visitor arrives. Drop-off here is usually a relevance or clarity problem: the message doesn't match what they expected, or the value isn't obvious above the fold.
2. Middle of funnel (consideration) — they engage: read features, view pricing, start the signup. Drop-off here is usually a friction or objection problem: too many form fields, a pricing surprise, a missing answer.
3. Bottom of funnel (action) — they convert and reach first value. Drop-off here is usually an activation problem: they signed up but never got to the moment the product pays off.

Naming the stage that's leaking points you at the kind of fix, before you've looked at a single line of code.

How to read a funnel correctly

• Compare relative drops, not absolute counts. The step that loses the largest percentage is the priority, even if a later step loses more raw people.
• Fix the steepest drop first. Improving a step that already converts well has little headroom; the steep step is where a fix compounds.
• Use a sensible time window. Give users enough time to complete all steps (a few days for a trial product), or you'll undercount conversions that legitimately take time.
• Keep the steps stable. Redefining a step mid-stream breaks the comparison with last month.

From concept to your own data

A funnel is only useful once it's built on your events. In practice you capture one event per step (signup_started, signup_completed, activated) and chart them in order — see how to build a signup funnel in PostHog for the concrete steps. Then the steepest drop is your roadmap.

If you'd rather have that drop found and the fix shipped as a Pull Request each week, that's what Velyr does — it reads your funnel and writes the code change for the step that's leaking.