True geodesic circles with unit toggle, presets, stats and GeoJSON/KML/GPX export.
By Aryan Khan, Founder & Editor · Updated October 2026
For example, a 25-mile radius around downtown Chicago covers approx. 1,964 square miles (5,085 km²) and reaches Evanston, Oak Park and Gary — but not Naperville, which sits just outside at 28.4 miles.
A radius turns the vague phrase “near here” into a boundary you can measure, share and defend. Three steps:
The Map Radius Tool draws a true circle around any place on the map. Set a center and a radius in miles or kilometers and it shows the circle with its area and circumference, drawn geodesically so the size stays honest anywhere on Earth. Free, no account needed.
Draw the honest coverage circle around a depot, kitchen or store before you promise a delivery zone. Then test the same area against real roads with the Drive Time Map — the circle is the promise, the road network is the truth.
House-hunters think in radii: within two miles of a school, within five of a station. A measured circle turns that wish into a search boundary you can hand to an agent or reuse on the next listing.
Leaflet drops, franchise territories and sales patches are all radius decisions. Drawing the circle first shows exactly which neighborhoods are in — and which competitor's patch you are about to overlap.
Buffers around a river, a proposed site or a protected area are standard planning inputs. Pair the circle with Population Within a Radius when the question becomes how many people the buffer contains.
A 25-mile (40.2 km) radius centered on downtown Chicago (41.8781, −87.6298) reaches Oak Park at approx. 8.0 miles (12.8 km), Evanston at 11.7 miles (18.8 km) and Gary, Indiana at 24.5 miles (39.4 km) — just inside the line. Naperville, at 28.4 miles (45.7 km), falls outside: a circle is a boundary, not a rough guess.
A 20 km (12.4 mi) radius around central Paris (48.8566, 2.3522) takes in Saint-Denis at approx. 8.9 km (5.5 mi), Orly at 12.7 km (7.9 mi) and Versailles at 17.4 km (10.8 mi) — all three inside the line, which is why a 20 km circle is a useful first sketch of the capital's day-trip field.
Circumference and area for the radii people draw most, from A = πr² and C = 2πr, labeled approx. — at these sizes the tool's geodesic figures on the sphere differ from the flat formulas by well under 1%.
| Radius | Circumference (mi) | Circumference (km) | Area (mi²) | Area (km²) |
|---|---|---|---|---|
| 1 mile | 6.3 | 10.1 | 3.1 | 8.1 |
| 2 miles | 12.6 | 20.2 | 12.6 | 32.5 |
| 5 miles | 31.4 | 50.6 | 78.5 | 203.4 |
| 10 miles | 62.8 | 101.1 | 314.2 | 813.7 |
| 25 miles | 157.1 | 252.8 | 1,963.5 | 5,085.4 |
| 50 miles | 314.2 | 505.6 | 7,854.0 | 20,341.7 |
| 75 miles | 471.2 | 758.4 | 17,671.5 | 45,768.9 |
| 100 miles | 628.3 | 1,011.2 | 31,415.9 | 81,366.9 |
Area is geometric coverage, not reachability: a river, a mountain range or a missing bridge can make the far side of a circle a long drive. For road-based reach, use the Drive Time Map.
MapBench draws a geodesic circle around the chosen centre and calculates its area and circumference. Because the boundary is defined by surface distance from one point, it is useful for rules expressed as a fixed radius: preliminary service zones, site buffers, event planning, property searches, facility comparisons and quick geographic coverage checks. Export options let the geometry move into other mapping workflows instead of remaining only a visual sketch.
The key limitation is conceptual rather than mathematical: equal straight-line distance does not mean equal travel time. A point ten miles away across a river or mountain can take much longer to reach than a point farther away along a motorway. For road-based service promises or commute planning, compare the circle with a Drive Time Map. For people or ZIP areas inside the radius, use the dedicated population and ZIP-radius tools so the geographic boundary is connected to an appropriate dataset.
A radius drawn on a web map is also not a legal property buffer or survey. The centre coordinate, map scale and source geometry matter, and legal setbacks can be defined by parcel lines or jurisdiction-specific rules rather than a simple point radius.
The most common errors come from using a correct result to answer the wrong geographic question. Keep these points in mind for Map Radius Tool:
Circles and polygons are geometric truths with semantic limits. A radius says nothing about rivers, one-way systems or response times; an area says nothing about what is inside it. The most expensive misuse is treating a geometric catchment as a service promise — which is why the isochrone tools exist as the temporal counterpart, and why the pages cross-link the two insistently. A second limit is resolution: drawn vertices capture the boundary you click, so curved shores want more clicks, and the perimeter grows (correctly) as you add them — the coastline paradox, politely present in every honest measurement tool.
Within geometry, the numbers are exact on the sphere: areas by spherical excess, boundaries by destination math, exports with their parameters embedded. The escalation ladder is short: cadastral precision needs licensed surveys; population-inside-shapes needs census blocks; drive-time promises need the routing engine. Used as the fast, auditable, shareable geometric layer that feeds those heavier instruments, this is exactly the right tool — and it says so.
Circle boundaries sample 128 bearings using spherical destination calculations with a mean Earth radius of 6,371.0088 km. Results are approximations, not ellipsoidal survey measurements; inspect the input centre and radius before exporting.
For source details, licences and model limitations, see Data Sources and Methodology.
Editorial guidance: MapBench explains the method and limitations so the tool can be used as a transparent reference, not as a black-box answer. For legal boundaries, safety-critical routing, surveying, engineering, regulated decisions or official statistics, verify the result with the responsible authority or a qualified professional.
Category: Radius & Area. Results are intended for everyday analysis and planning unless a page explicitly states otherwise.
From a circle to a decision
These illustrative scenarios use simple circle geometry. They are not measured customer counts, actual service territories or travel-time guarantees.
Imagine a bakery choosing between a 3-mile and a 6-mile delivery zone. Doubling the radius quadruples the geometric area; it does not simply double the workload. Check actual routes before advertising delivery times.
Worked example
A 3-mile radius has a 6-mile diameter. Using πr², its approximate area is 28.3 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
For a hypothetical office search, an 8-mile circle makes a useful first cut. A property inside the circle may still involve a long commute because of a river crossing, indirect roads or congestion. Use a route calculation for the final shortlist.
Worked example
A 8-mile radius has a 16-mile diameter. Using πr², its approximate area is 201.1 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
A 2-mile buffer around a venue can help you start looking for accommodation or meeting places. The circle describes distance only: it does not confirm pedestrian access, opening hours, availability or a safe walking route.
Worked example
A 2-mile radius has a 4-mile diameter. Using πr², its approximate area is 12.6 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
Place a 15-mile circle around a proposed service base to compare its geometric footprint with another location. Overlapping circles are not separate markets, and adding their areas would count the overlap twice.
Worked example
A 15-mile radius has a 30-mile diameter. Using πr², its approximate area is 706.9 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
A community equipment library could start with a four-mile search around its storage location. The circle helps volunteers shortlist pickup points using one consistent rule, rather than judging closeness from a distorted zoom level. It does not show which locations offer parking, accessible entrances or permission to use the premises. Verify each shortlisted address and compare actual routes before announcing a collection point.
Worked example
A 4-mile radius has a 8-mile diameter. Using πr², its approximate area is 50.3 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
A small retailer considering a six-mile catchment can use a circle to define the question clearly. The resulting area alone says nothing about how many customers live there: a lake, an industrial estate and a residential neighbourhood occupy area differently. If you add population information, record the dataset, boundary type and estimation method. Do not multiply area by an unrelated citywide density and present that as a measured customer count.
Worked example
A 6-mile radius has a 12-mile diameter. Using πr², its approximate area is 113.1 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
Suppose an organizer wants to invite venues within twelve miles of a meeting point. Keep the same centre coordinate for every check, particularly when a place search returns a broad city centre rather than the intended entrance. A venue very close to the circle edge deserves a direct point-to-point measurement. A small change in the selected centre can move a borderline venue from inside to outside without either calculation being wrong.
Worked example
A 12-mile radius has a 24-mile diameter. Using πr², its approximate area is 452.4 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
For a classroom exercise, compare five-mile and ten-mile circles around the same point. The radius doubles, but the area grows by a factor of four because area depends on the square of the radius. Ask students to predict the change before calculating it. Keep the units identical and distinguish area, diameter and perimeter; each measures a different property of the same shape.
Worked example
A 5-mile radius has a 10-mile diameter. Using πr², its approximate area is 78.5 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
Two proposed service locations can each have a twenty-mile search area, but their combined coverage is not automatically twice one circle's area. Where the circles overlap, the same ground belongs to both. Use multiple circles to inspect that overlap visually, then use an appropriate polygon-union workflow if you need a numerical combined area. The circle statistics should not be mistaken for a union-area calculation.
Worked example
A 20-mile radius has a 40-mile diameter. Using πr², its approximate area is 1256.6 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
A report is easier to check when it records the centre coordinate, radius, unit and purpose of the boundary. For a ten-mile scenario, save those inputs alongside the map rather than sharing only a cropped screenshot. Explain that the boundary is a planning assumption, not an official jurisdiction or verified travel-time zone. Someone reviewing the report can then repeat the geometry and decide whether that assumption fits the decision.
Worked example
A 10-mile radius has a 20-mile diameter. Using πr², its approximate area is 314.2 square miles. This flat-circle approximation is useful for these small-radius comparisons, not a substitute for the map’s geographic calculation.
Choose the measurement that matches your question. Equal distance does not mean equal accessibility.
| Your question | Use | Important limit |
|---|---|---|
| What is within 10 miles? | Radius circle | No roads or traffic considered |
| How far is the drive? | Route distance | Depends on routing data and mode |
| What can I reach in 30 minutes? | Drive-time area | Estimated travel time, not a promise |
Coverage: Worldwide. Search, basemap and external data requests may use third-party services; browser-based does not mean every operation is offline. Read the source and licence notes, calculation methodology and privacy policy. If a result looks inconsistent, report a correction with the inputs and mode used.
Clear answers about the calculation, accuracy and appropriate use.
The circle uses spherical calculations rather than a flat-map radius. It is not an ellipsoidal survey measurement.
No. A radius is a geometric circle around a centre point. Driving reach depends on the road network and usually has an irregular shape.
Yes for first-pass planning. Use a drive-time or road-network tool when accessibility matters more than straight-line coverage.
No. MapBench measurements are planning/reference outputs unless a page explicitly states otherwise. Use a licensed surveyor for legal boundaries.
Because the map is flat and the Earth is not. Web maps stretch east–west distances as you move away from the equator, so a true circle drawn geodesically appears as an oval on screen — most noticeably at high latitudes. The measurements (radius, circumference, area) are computed on the sphere and stay correct even when the picture looks stretched.
The circle is drawn with geodesic mathematics on the WGS84 sphere, so the area is a true surface area rather than a flat-map estimate. It is suitable for planning, marketing and research; legal boundaries and land disputes still need a licensed survey.
The radius is the distance from the center to the edge — the number you enter here. The diameter is twice that, edge to edge through the center. A “10-mile radius” covers a circle 20 miles across, which is four times the area of a 5-mile radius, not two times.
Area grows with the square of the radius. Doubling the radius from 5 to 10 miles multiplies the area by four (approx. 78.5 to 314.2 square miles). This is the most common surprise in radius planning, and the table on this page shows the growth across the common sizes.
Yes. The tool works in both units, and every figure on this page is given in miles and kilometres. For European examples the kilometre figure is listed first; for US examples, miles come first.
Yes — the result is encoded in the page address, so the link reopens the same center and radius for anyone you send it to. That makes a radius decision easy to put in an email, a listing or a planning document.
A circle answers “how far as the crow flies” — when the question becomes “how far by road”, continue to the Drive Time Map, which draws reach on the real network. To count what falls inside your circle, use Population Within a Radius for people, Cities Within a Radius for settlements, or ZIP Codes Within a Radius for a postal list you can mail to.
Calculations are documented with their assumptions, limitations and source context rather than presented as unexplained answers.
Reviewed and maintained by Aryan Khan, Founder & Editor of MapBench.
Map Radius Tool sits in the radius & service area cluster, alongside 18 other tools that answer neighbouring questions with different methods or datasets.
When this answer is only part of the job, these clusters cover the next step.
How to Draw a Radius on Google Maps — Google Maps has no radius button. Here are the exact workarounds to draw a radius circle — plus free tools that do it in one click.
Click the map to set center · Drag the orange handle to resize