Funnel Conversion Calculator
Track how many people survive each stage of a funnel, and find the step that costs you most.
A funnel multiplies.
How the funnel conversion calculator works
A funnel multiplies. Four stages at 50% each leave 6.25% at the end, not 50%, and that compounding is why small improvements early are worth so much more than they look.
The stage worth fixing is rarely the worst one in isolation. It is the one where the largest number of people are lost, which depends on both the drop rate and how many reached that stage. A 90% drop at the very bottom of a thin funnel loses fewer people than a 30% drop at the top.
Enter the count reaching each stage, largest first.
Formula: overall rate = product of the stage rates
Worked examples
| Inputs | Overall conversion | Note |
|---|---|---|
| A five-stage funnel | 2% | 2% overall |
| A short funnel | 5% | 5% |
| Even drop-off | 12.5% | 12.5% — four halvings |
FAQFrequently asked questions
How do I calculate funnel conversion?
Divide the final stage by the first. The stage-to-stage rates multiply to give it.
Why does a funnel drop off so fast?
Because the rates multiply. Four stages at 50% each leave 6.25%, not 50%.
Which stage should I fix first?
Usually the one losing the most people, not the one with the worst percentage — a bad rate late in a thin funnel affects few people.
Does improving the top of the funnel help most?
Often, because every later stage compounds on it. But it is also usually the least qualified traffic.
Can a funnel stage grow?
Not as measured here. If a later stage has more people, the stages are counting different things.
Where these figures come from
- Interactive Advertising Bureau — measurement guidelines — the impression and viewability definitions CPM depends on
- Advertising Standards Authority — the UK advertising regulator
Last checked: September 2026. These are standard industry definitions; where platforms disagree, the page says so.