Marketing Conversion Rate Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/6/2026
The conversion rate is calculated with (number of conversions ÷ number of visitors) × 100. With 50 conversions out of 2,000 visitors and €500 spent, the conversion rate is 2.5% and each conversion costs €10.
Explanation
Conversion rate is one of the most closely tracked metrics in digital marketing: it measures the proportion of visitors who complete the desired action (a purchase, a newsletter sign-up, a quote request), relative to the total number of visitors or clicks received. A high conversion rate generally indicates a good match between the traffic generated (its source, its targeting) and the offer presented on the landing page. This calculator adds a second, complementary metric, cost per conversion, by dividing the total ad spend by the number of conversions obtained — a direct profitability indicator, to be compared against the average value of a conversion (the average order value for an e-commerce site, for example) to know whether a campaign is actually profitable. These two metrics should always be read together: a high conversion rate with a cost per conversion higher than the value generated by each conversion still amounts to a losing campaign, despite an appearance of good performance. Our percentage calculator can also be used to easily compare two conversion rates against each other, for example to measure a campaign's improvement from one month to the next.
Example: an online advertising campaign
Inputs
Visitors: 2,000. Conversions: 50. Ad spend: €500.
Calculation
Conversion rate = (50 ÷ 2000) × 100 = 2.5%. Cost per conversion = 500 ÷ 50 = €10.
Result
This campaign converts 2.5% of its visitors, at a cost of €10 per conversion obtained.
Frequently asked questions
What counts as a good conversion rate?
There is no universal threshold: a good conversion rate depends heavily on the industry, the type of conversion targeted (an immediate purchase converts far less often than a simple newsletter sign-up), and the traffic source. Benchmarks published by industry (e-commerce, B2B lead generation, etc.) give a more relevant reference point than a single figure valid everywhere.
Why track cost per conversion in addition to the conversion rate?
The conversion rate alone says nothing about a campaign's profitability: a high rate achieved with very high ad spend can still be a loss, while a more modest rate with a low cost per conversion can be highly profitable. These two metrics complement each other, and should always be compared against the actual value generated by each conversion.
Should the number of "visitors" be unique visitors or clicks?
Both uses exist depending on context: a conversion rate calculated on ad clicks (useful for evaluating a specific paid campaign) differs from a rate calculated on unique site visitors (useful for evaluating a page's overall performance). What matters is staying consistent from one period to the next so that comparisons over time remain valid — see also our CPM and CPC advertising calculator for similar reasoning applied to advertising spend.