Conversion Rate (CR) is the share of traffic that ends with a desired action — a Goal such as a purchase, signup, or Lead submission. In plain terms: “Out of all opportunities, how many converted?” CR is a workhorse metric for prioritizing experiments, sizing impact, and comparing channel efficiency across segments and time.
Formula
Conversion Rate = (Number of Conversions ÷ Measurement Base) × 100%
The “measurement base” must be explicit. Most teams use Session (visit-level view) or User (people-level view). Ad teams also compute click-based CR.
| Base (denominator) | Answers the question | Typical use |
|---|---|---|
| Session | What % of visits convert? | Site & funnel optimization |
| User | What % of people convert? | Growth & retention |
| Ad clicks | What % of clicks convert? | Performance marketing |
Mini-example:
- 120 purchases from 5,000 sessions ⇒ 2.4% session CR
- Same 120 purchases from 3,200 users ⇒ 3.75% user CR
Declare the base every time to avoid mismatched comparisons.
Why it matters
CR compresses complexity into an actionable ratio. You can grow by buying more traffic, or by making existing traffic work harder. Improving CR multiplies revenue without proportional budget increases. It’s central to diagnosing friction in the Goal Funnel / Multi-Channel Funnel and to forecasting, CAC/ROI planning, and experiment design.
Variants you’ll meet
- Ecommerce Conversion Rate: purchases per session/user.
- Macro vs Micro: Macro Conversion / Micro Conversion to separate primary outcomes from supportive actions (e.g., Goal Completion for add-to-cart, newsletter).
Practical notes before comparing CRs
- State the denominator (session vs user vs click). Numbers — and conclusions — change.
- Count logic: in multi-step flows, cap at one conversion per session (or per user) to prevent inflation.
- Segment ruthlessly: by channel, Landing Page, Device Category (Desktop, Mobile, Tablet), Geography (Country, City, Language). Averages hide truth.
- Traffic quality matters: CR interacts with Click-Through Rate (CTR) and Cost Per Acquisition (CPA); cheap clicks can crater CR.