# Reach

> The number of unique users who saw an ad at least once, counting each person only once no matter how many times the ad was shown.

**Reach** is the number of unique users who saw an ad at least once, counting each person only once regardless of how many times the ad was shown. It measures audience *size*, while impressions measure audience *exposure*.

## How AnyTrack reports reach

Reach appears in the [Campaign Report](/docs/advanced-options-campaign-report#available-metrics) Performance metrics as "the total number of unique users who have seen your ad," fetched from Meta Ads, Google Ads, and TikTok Ads. Reach is also the denominator of Frequency (`Total Impressions / Unique Reach`).

## Reach vs Impression

- [Impression](/glossary/impression) — one person who sees an ad five times is five impressions but counts as one in reach; the ratio between the two is your frequency.