How to draw a radius on a map
The map radius tool lets you draw a circle of any distance around any point on Earth. It uses geodesic calculations that account for the curvature of the planet, so the radius is accurate whether you're measuring a 5-mile delivery zone in Manhattan or a 500-mile coverage area across the Great Plains.
10 practical uses for radius maps
A radius circle is one of the most versatile geographic tools available. Here are ten real-world scenarios where drawing a radius on a map solves a practical problem, with specific numbers and examples for each.
1. Restaurant delivery zones
Restaurant owners use radius maps to define how far they'll deliver food. Most restaurants limit delivery to 5-10 miles to keep food hot and drivers efficient. A 5-mile radius covers 78.5 square miles — typically enough for an urban restaurant to reach 50,000-200,000 potential customers depending on population density.
A pizza shop in downtown Denver sets a 4-mile delivery radius. This covers 50.3 square miles including Capitol Hill, Cherry Creek, and parts of Aurora — roughly 180,000 residents. They charge $3 extra for deliveries beyond 2.5 miles.
2. House hunting commute analysis
Home buyers draw a radius around their workplace to visualize how far they're willing to commute. A 15-mile radius from an office captures all homes within a reasonable drive, while a 25-mile radius shows the outer limits of suburban commuting. The average American commute is 27.6 minutes each way (about 15-20 miles in most metro areas).
A family relocating to Seattle draws a 12-mile radius around Microsoft's Redmond campus. The 452 sq mi area includes Bellevue, Kirkland, Issaquah, and Woodinville — all within a 25-minute average commute. They eliminate neighborhoods outside this radius to focus their home search.
3. Emergency evacuation planning
Emergency managers use radius maps to define evacuation zones around hazards. The Nuclear Regulatory Commission requires a 10-mile Emergency Planning Zone (EPZ) around nuclear plants for immediate evacuation, and a 50-mile zone for food/water contamination monitoring. Industrial facilities often use 1-5 mile radii for chemical spill scenarios.
The 10-mile EPZ around Three Mile Island nuclear plant in Pennsylvania encompasses 314 square miles and includes parts of Dauphin, Lancaster, and York counties — approximately 210,000 residents who receive emergency preparedness information and potassium iodide tablets.
4. Retail site selection
Retail analysts draw radii around potential store locations to estimate the customer base. A typical grocery store draws customers from a 3-5 mile radius (primary trade area), while big-box stores like Costco attract shoppers from 10-15 miles away. The number of households within the radius determines if a location is viable.
A coffee chain evaluating a site in Austin, TX draws a 2-mile radius to identify their primary market. The 12.6 sq mi area contains 45,000 residents, 8,000 daytime workers, and 3 competing coffee shops. They need at least 30,000 people within 2 miles to hit their sales targets.
5. School district enrollment boundaries
School administrators analyze enrollment patterns by drawing radii around schools. Elementary schools typically draw students from a 1-2 mile radius (walking distance), middle schools from 3-5 miles, and high schools from 5-10 miles. These radii help identify where to build new schools or redraw attendance zones.
A suburban Phoenix school district draws 1.5-mile radii around each elementary school (7.1 sq mi each). Where circles overlap, families can choose between schools. One area with no coverage — a 2-mile gap between circles — identifies where a new school is needed to serve 800 students currently being bused.
6. Cell tower coverage mapping
Telecom engineers use radius maps to visualize cell tower coverage. A typical macro cell tower covers 1-5 miles in suburban areas, but only 0.25-1 mile in dense urban environments due to building interference. Rural towers can reach 10-25 miles with line-of-sight terrain. Multiple overlapping circles show network coverage.
A wireless carrier mapping coverage in rural Montana draws 15-mile radii around each tower. With towers spaced 25 miles apart along I-90, the 707 sq mi circles overlap by 5 miles, ensuring continuous highway coverage. A dead zone between Bozeman and Livingston requires a new tower to close the 8-mile gap.
7. Running and cycling route planning
Athletes use radius maps to discover new training routes within a set distance from home. A 3-mile radius reveals all roads, trails, and parks reachable on a 6-mile out-and-back run. Cyclists often plan routes within a 15-25 mile radius for 60-100 mile weekend rides, ensuring they can loop back without running out of daylight.
A marathon trainee in Portland draws a 10-mile radius from their apartment. The 314 sq mi area includes Forest Park, the Springwater Corridor, and routes across 5 bridges — giving them variety for 18-20 mile long runs without repeating the same path. They discover a new trail system they'd never noticed before.
8. Service business territory definition
Home service businesses (plumbers, electricians, landscapers) use radius maps to define their service area. Most trades limit service to 20-30 miles to minimize drive time between jobs. A 25-mile radius covers 1,963 square miles — far more area than any single provider can effectively serve, so many businesses divide territories among technicians.
An HVAC company in Charlotte, NC sets a 30-mile service radius from their warehouse. The 2,827 sq mi area covers Mecklenburg, Gaston, Cabarrus, and Union counties — 2.5 million residents. They assign each of their 8 technicians a wedge of the circle to minimize overlap and drive time between appointments.
9. Drone flight planning (Part 107)
Commercial drone pilots use radius maps to check airspace restrictions. FAA Part 107 requires pilots to stay within visual line-of-sight (typically 1-2 miles) and avoid flying within 5 miles of airports without authorization. Drawing these radii on a map helps pilots identify no-fly zones and plan compliant flight paths.
A real estate photographer in San Diego draws 5-mile radii around Lindbergh Field (SAN), Montgomery-Gibbs (MYF), and Brown Field (SDM). The overlapping 78.5 sq mi circles reveal that most of central San Diego requires LAANC authorization. Only areas east of El Cajon fall outside all airport radii.
10. Radio station coverage analysis
Broadcasters use radius maps to estimate their signal reach. An FM radio station at 100 watts typically covers 5-10 miles, while a 50,000-watt station can reach 60-100 miles depending on terrain and antenna height. These coverage circles help stations sell advertising by quantifying their potential audience.
A 50,000-watt FM station in Kansas City draws a 70-mile primary coverage radius. The 15,394 sq mi circle spans from St. Joseph to Topeka to Warrensburg, reaching 2.4 million people across 12 counties in Missouri and Kansas. This data supports their rate card showing $85 CPM for drive-time advertising.
The math behind radius calculations
The area enclosed by a radius circle follows the formula A = π × r², where r is the radius distance. This means doubling the radius doesn't double the area — it quadruples it. A 10-mile radius covers four times more ground than a 5-mile radius (314 vs. 78.5 square miles).
The perimeter (circumference) of the circle is C = 2 × π × r. For a 25-mile radius, the circumference is approximately 157 miles — that's the total distance around the edge of your coverage area.
This tool uses the Haversine formula and WGS84 ellipsoid model (the same reference system used by GPS) to calculate distances on the Earth's curved surface. For radii under 100 miles, the difference between a geodesic circle and a flat-plane circle is small. At 500 miles, a flat-plane calculation would overestimate the area by roughly 3-5% depending on latitude.
| Radius (mi) | Area (sq mi) | Perimeter (mi) | Real-world equivalent |
|---|---|---|---|
| 1 | 3 | 6 | Small neighborhood |
| 5 | 79 | 31 | Town / small city |
| 10 | 314 | 63 | Metro commute zone |
| 25 | 1,963 | 157 | Regional service area |
| 50 | 7,854 | 314 | Large metro + suburbs |
| 100 | 31,416 | 628 | Multi-county region |
| 250 | 196,350 | 1,571 | Multi-state area |
| 500 | 785,398 | 3,142 | Coast-to-coast scale |
Related tools and resources
If you need to measure an irregular area rather than a circle, the Map Area Calculator lets you draw a custom polygon on the map and calculates the enclosed area in square miles, kilometers, acres, and hectares.
To find out which county, city, or ZIP code a specific point falls in, use the What County Am I In? tool. It uses the same GPS and address search capabilities but returns administrative boundaries instead of distance circles.
For straight-line and driving distances between two specific locations, the Distance Between Two Places calculator provides both the as-the-crow-flies distance and the approximate driving route.
Exploring a specific state? Our interactive county map show every county with population data, county seats, and demographic breakdowns — useful context when you're defining a service area within a state.
Frequently asked questions
Map tiles are provided by OpenFreeMap using OpenStreetMap data (ODbL license). Address autocomplete uses the Photon geocoder by Komoot. Reverse geocoding uses Nominatim. Geodesic circle geometry is calculated by Turf.js using the WGS84 ellipsoid model (EPSG:4326), the same coordinate reference system used by GPS. Map rendering uses MapLibre GL JS, an open-source WebGL map library. All tools and data sources are open-source and free to use.