A practical way to pick a radius that hits the right people—without paying for everyone nearby
Geofencing works best when it’s treated like an engineering decision, not a guess. The radius you choose determines three things at once: audience reach (how many devices can qualify), precision targeting (how many are truly “in” your location), and efficiency (how much budget goes to the right impression at the right moment). This guide walks through a clear framework you can use to set geofence radii for retail, events, competitor conquesting, and multi-location campaigns—then optimize with real-world performance signals.
Why “radius” is rarely just a number
A geofence is typically a circular boundary around a point (or a polygon around a venue). Radius matters because mobile location signals vary by context—GPS, Wi‑Fi, and cellular triangulation don’t behave the same indoors, downtown, or on a highway. In practice, that means a tight radius can undercount the people you want (missed reach), while an oversized radius can scoop up “drive-bys” and neighboring businesses (wasted impressions).
The best radius is the one that matches your conversion intent window (how close someone must be to be meaningfully “in-market”) and the expected location error in that environment.
A simple radius framework ConsulTV teams use
Radius = Intent Zone + Error Buffer
Intent Zone = the real-world area where a person is reasonably likely to take the action you care about (walk in, attend, request a quote).
Error Buffer = extra space to account for typical location inaccuracy in that context.
If you can estimate both, your geofence decisions become consistent across channels (display, OTT/CTV, streaming audio, social retargeting) and easier to explain in reporting—especially when you’re running white-labeled dashboards for agency clients.
What affects precision (and how it changes your radius)
1) Venue type: indoor vs. outdoor
Indoor locations (malls, hospitals, convention centers) can reduce GPS reliability; devices may lean on Wi‑Fi/cellular, which often increases error. If the business is inside a complex, plan for a larger buffer or use polygons and exclusions to avoid capturing the whole parking lot plus neighboring tenants.
2) Speed of movement: foot traffic vs. drive-by
Around highways, a “nearby” device may never have realistic intent to stop. Tighter radii plus dayparting and on-site dwell filters reduce false positives. For walkable downtown areas, slightly larger intent zones can work if your offer is genuinely “near me” relevant.
3) Competitive density: neighbors, anchors, and shared parking
If your location shares a lot with other brands, a large radius inflates reach while diluting accuracy. In these cases, consider a smaller radius (or a polygon), plus exclusion fences around obvious spillover areas (anchors, adjacent lots, transit stops).
Quick radius starting points (then refine with data)
| Use Case | Typical Intent Zone | Recommended Radius Range | Notes for Better Precision |
|---|---|---|---|
| Single storefront (walk-in) | Building + immediate frontage | 100–300 ft | Use exclusions for shared lots; add dwell-time filters if available. |
| Big-box / standalone with parking | Store + full parking footprint | 300–800 ft | If near a highway, consider shrinking and adding dayparting to business hours. |
| Mall / multi-tenant complex | Entrances + relevant wing/anchor area | 500 ft–1 mile | Polygons outperform circles; exclude nearby shopping centers to prevent spill. |
| Event venue (limited time) | Venue + immediate approach routes | 0.25–2 miles | Run tight during event hours; expand pre/post for awareness and retargeting pools. |
| DMA-wide “near me” awareness | City/region-level reach | 5–10+ miles | Layer with demo/behavioral/contextual filters to keep relevance high. |
These are starting ranges. The “right” number depends on your offer, the environment, and the level of spillover you can tolerate before performance metrics (CTR, visitation rate, CPA) soften.
Did you know? Quick facts that impact radius decisions
“Small” fences can still work: some retail guidance notes a minimum geofence radius as low as ~10 meters in certain systems—useful for tight footprints when you have clean POIs and want maximum precision.
Phones don’t always “snap” to the right spot: real-world mobile location accuracy can vary widely by signal conditions and environment, which is why an error buffer protects you from under-delivering.
Most waste comes from edges: if your radius is too big, a disproportionate share of impressions often comes from the fence perimeter—people who are “technically inside,” but behaviorally unlikely to convert.
Step-by-step: How to calculate a geofence radius you can defend in reporting
Step 1: Define your “success action” and its distance reality
Write down the action you want: store visit, appointment request, event entry, form fill, or call. Then decide how far away someone can be and still reasonably be “in-market.” For a storefront, it might be “on the block.” For an event, it might be “within a couple miles during the hour before doors.”
Step 2: Map the physical footprint (not just the address pin)
A pin-drop radius ignores parking, entrances, and neighboring tenants. If your location is a complex, treat polygons and exclusions as your default. If you must use a circle, base it on the farthest point you consider “valid intent” (e.g., the edge of the lot, the venue gate line, or the correct entrance).
Step 3: Add an error buffer (and make it smaller when you can)
Your buffer is what protects delivery when devices report a slightly shifted location. Start conservative. If performance suggests too many false positives, shrink the radius and use supporting layers (demo targeting, contextual, behavioral, or search retargeting) to maintain reach without widening the fence.
Step 4: Plan your optimization loop before launch
Decide what “good” looks like by channel. For example:
Step 5: A/B test radii (not just creative)
Run two radii in parallel for the same location and audience layers (example: 250 ft vs. 600 ft). Keep budgets similar. After a meaningful sample, compare cost per qualified outcome—not just clicks. This is one of the fastest ways to find your “sweet spot” for audience reach vs. precision targeting.
Local angle: how U.S. market reality changes geofence decisions
Across the United States, two patterns show up repeatedly:
1) Suburban sprawl increases “accidental reach.” Large parking lots and multi-tenant retail mean a 0.5–1 mile radius can capture several shopping areas at once. If your KPI is foot traffic attribution, tighten the fence and use exclusions to keep visits credible.
2) Dense downtowns demand smarter shapes. A small circle can still include multiple floors, adjacent buildings, and transit corridors. Polygon geofences (plus building/POI-level logic when available) are often the most cost-effective way to preserve precision without over-shrinking delivery.
CTA: Get your geofence radius plan reviewed by a programmatic team
If you’re running multi-location campaigns (or managing them for clients), a second set of eyes can prevent common radius mistakes—especially around shared lots, malls, campuses, and competitor conquesting.
FAQ: Geofence radii, reach, and precision
What’s a good default geofence radius for a local business?
If the goal is true walk-in intent, start around 100–300 feet for a typical storefront and expand only if delivery is too limited. For standalone locations with large lots, 300–800 feet is a common starting range.
Why did my bigger radius “perform worse” even though reach increased?
Bigger fences tend to pick up low-intent devices (people passing by, visiting neighboring businesses, or sitting in nearby residences). That can increase impressions and clicks while reducing qualified actions—so CPA rises even though top-line reach looks healthy.
Should I use a circle radius or a polygon geofence?
Use a polygon when your footprint is irregular (malls, campuses, venues, downtown blocks) or when neighboring businesses create spillover risk. Use circles when the location is simple and standalone or when you need speed for multi-location scaling.
How do I balance geofencing with privacy-safe measurement?
Focus on aggregated, de-identified reporting and consistent methodology (clear lookback windows, suppression/exclusions, and repeatable definitions of “visit”). Pair location strategies with contextual and first-party tactics (site retargeting, search retargeting, and conversion events) to reduce reliance on any single signal.
What’s the fastest way to find the best radius for my campaign?
Run a controlled test: two radii, same creative and audience layers, same dayparts, similar budgets. Compare cost per qualified outcome (visits, leads, calls) rather than optimizing to clicks alone.
Glossary
Want to align geofence radii with omnichannel delivery (display, OTT/CTV, streaming audio, social) and white-labeled reporting? Explore ConsulTV’s programmatic solutions and request a workflow review via the contact page.