Website conversion rate: choose the right denominator
Calculate conversion rate from visits and completed actions without mixing users, sessions or ad impressions.
How it works
Conversion rate is completed conversions divided by the chosen eligible population, multiplied by 100. Decide whether the denominator is sessions, unique users or qualified leads. A purchase conversion rate based on visits is not interchangeable with one based on ad impressions. Count the same event and population in both time periods, and define whether repeated purchases count.
Use the inputs from your own situation and keep the units consistent. A calculator gives an arithmetic estimate under the assumptions you enter; compare it with real records before making a decision.
Worked example
A page receives 8,000 sessions and records 160 completed purchases. Its session conversion rate is 160 ÷ 8,000 × 100 = 2%. If 6,000 unique users generated those sessions, a user-based calculation is 2.67% only if the 160 conversions are attributed consistently to users. The two percentages answer different questions.
What to check
Bot traffic, consent loss, attribution windows and incomplete checkout tracking change the measurement. A rate can rise while total sales fall if traffic shrinks. Inspect volume and revenue alongside the rate; a small number of conversions can swing the result widely. Avoid claiming that a calculator predicts future performance.
Practical next step
Define the event, denominator and reporting window in writing. Compute the baseline, segment by channel and device, and use the same definitions for a later comparison.
Related calculators and articles
conversion rate, ad revenue. unit price bulk discounts.
Save your assumptions and repeat the calculation if an input changes. The linked article explains a neighboring decision that this single formula does not settle.