Reach
Also: Unique reach, Net reach, Audience reach, Portee, Couverture
The number of unique people exposed to your message in a given period. Unlike impressions, reach counts each person once, no matter how often they see it.
What It Is
Reach is the count of unique individuals exposed to a message, campaign, or content during a defined time window. The key word is *unique*: if one person sees an ad five times, they add 1 to reach and 5 to impressions. Reach answers the question "how many people did we touch?" while impressions answer "how many times was it served?"
Reach is usually expressed as:
- An absolute number (for example, 2.4 million people)
- A percentage of a target population (for example, 38% of adults 25 to 54 in a market)
Why it matters
Reach measures the breadth of exposure and is a core input for planning and evaluation:
- Awareness building: new products and brands need broad reach before conversion can scale.
- Deduplication: because it removes double counting, reach is a truer measure of audience size than raw impressions.
- Efficiency ceiling: once you have reached most of your addressable audience, extra spend mostly increases frequency (repeat exposures), not reach.
How it is used in practice
- Frequency pairing: reach is almost always read alongside average frequency. `Impressions = Reach x Average Frequency`. Planners set a target frequency (often 3 to 10 exposures) and solve for the reach a budget can buy.
- Incremental reach: when adding a channel, the useful metric is *net new* reach, the unique people not already reached elsewhere.
- Effective reach: the share of the audience reached at least N times (the minimum thought to drive an effect).
- Cross-platform measurement: deduplicating reach across TV, social, and web is hard and is where identity resolution and panel or modeled data come in.
Worked Example
A campaign is served 900,000 impressions. Log analysis shows the ad was seen by 300,000 unique people.
- Reach = 300,000
- Average frequency = 900,000 / 300,000 = 3.0
If the target market is 1,000,000 people:
- Reach % = 300,000 / 1,000,000 = 30%
Adding a second channel serves 400,000 impressions to 250,000 people, but 100,000 already saw the first channel. The incremental reach is only 150,000, lifting total unique reach to 450,000 (45%). This shows why stacking channels yields diminishing unique audience even as impressions climb.
Common Pitfalls
- Confusing reach with impressions or clicks.
- Summing per-channel reach without deduplication (double counts people).
- Chasing reach when the campaign goal is conversion, where frequency and targeting matter more.
See also
Frequently asked questions
What is the difference between reach and impressions?
Reach counts unique individuals exposed to a message; impressions count every exposure served. If one person sees an ad five times, that is 1 in reach and 5 in impressions. The two are linked by a simple identity: Impressions = Reach x Average Frequency.
How is reach expressed in a media plan?
Either as an absolute number of unique people (2.4 million individuals) or as a percentage of a defined target population (38% of adults aged 25 to 54 in a market). The percentage form is more useful for planning because it shows how much of the addressable audience remains untouched.
Why does extra budget stop increasing reach at some point?
Because once most of the addressable audience has been touched, additional spend mostly buys repeat exposures to the same people, which raises frequency rather than reach. This efficiency ceiling is the main reason planners track net new reach when they add a channel instead of total impressions.
How do you calculate incremental reach when adding a second channel?
Subtract the overlap with audiences already reached. Example: a first channel reaches 300,000 people; a second channel touches 250,000 people, of whom 100,000 already saw the first. Incremental reach is 150,000, bringing total unique reach to 450,000, not 550,000.
What is effective reach and how does it differ from plain reach?
Effective reach is the share of the audience exposed at least N times, N being the minimum number of exposures thought to produce an effect (planners often target 3 to 10). Plain reach counts anyone touched once, which can overstate real impact when a single exposure is too weak to register.