What are unique visitors and how are they counted?
How unique visitors are counted, why numbers often differ between tools, and why advertisers care about real people rather than browsers.
Written by Samhub with the help of AI·Updated 13 Oct 2026·3 min readUnique visitors is the number of different people, or in practice browsers or devices, that visited a site in a period, each counted once however many times they came back.
How unique visitors are counted
Most tools count unique browsers using a cookie or device ID. One reader on a phone and a laptop counts as two, and a reader who clears cookies counts again. That is why tools often report different numbers.
Related metrics
| Metric | Counts |
|---|---|
| Page views | Every page load |
| Visits (sessions) | Each separate visit |
| Unique visitors | Different browsers or people |
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Why people matter more than browsers
Addressability at Stampen Media after moving its reader data into one layer with Samhub.
Frequently asked questions
Because one person on several devices or browsers is counted more than once.
Use the period your buyers plan in. Weekly and monthly are common for campaigns.
Close. Reach usually means unique people who saw a specific ad or content.
With logins and an ID graph that links a reader’s devices.
Related terms
How many times pages were loaded.
How many ads were shown versus how many people saw them.
Links one reader’s visits across devices and logins.
The share of your audience you can recognize and target.
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