Conversion rate

Conversion rate is the share of people who complete a desired action out of those who had the chance to. For a form it is usually completions divided by starts; for a lead funnel it is completed sessions divided by entries; for a landing page it is goal completions divided by visits. It is the single most important number for judging whether an intake surface is working.

What counts as healthy varies by surface. A contact form often completes 70-90% of starts, a qualifying lead form 40-60%, a well-built quiz funnel commonly converts 10-25% of paid traffic against the 2-5% typical of a landing-page form. The strongest lever on a form's conversion is field count - every optional field you remove removes a reason to abandon.

Measuring it requires tracking the funnel stages (views, starts, completions) so you can see where people drop, not just that they did. The forms guide and funnels guide cover the levers and the analytics for each.