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Distance & area

Radius map

Draw a circle around any point and see how big it is and which states and counties it covers.

Center of the circle
or click on the mapor tap the map

Loading the map…

Result

Area
31,414mi²
Perimeter
628.3 mi
Diameter
200 mi

To give you an idea

About the same as Maine

Your circle31,414 mi²

Maine30,845 mi²

States it touches · 3

  • Kansas
  • Missouri
  • Nebraska

Counties it touches · 73

  • Allen County, KS
  • Anderson County, KS
  • Andrew County, MO
  • Atchison County, KS
  • Atchison County, MO
  • Barton County, MO
  • Bates County, MO
  • Benton County, MO
  • Bourbon County, KS
  • Brown County, KS
  • Buchanan County, MO
  • Caldwell County, MO
  • Camden County, MO
  • Carroll County, MO
  • Cass County, MO
  • Cedar County, MO
  • Chariton County, MO
  • Clay County, MO
  • Clinton County, MO
  • Coffey County, KS
  • Cooper County, MO
  • Crawford County, KS
  • Daviess County, MO
  • DeKalb County, MO

Counts every state and county the circle reaches into, even a little.

What’s inside this radius?

Open the same circle in another tool, no need to search again.

ZIP codes in a radiusEvery ZIP code inside, with its population. Cities in a radiusThe cities and towns inside, by distance. Population in a radiusHow many people live inside this circle.

Save or share this circle

How to use it

  1. 1

    Pick the center

    Type an address, a town or a place. You can also use your location or click on the map.

  2. 2

    Set the radius

    Drag the slider, type a number or tap a quick value: 5, 10, 25, 50 or 100. Switch to kilometers if you prefer.

  3. 3

    Read the result and share it

    You’ll see the area, the perimeter and the states and counties it touches. Copy the link: whoever opens it sees the same circle.

What it’s for

  • Delivery area

    Show how far you deliver from your store, shop or kitchen, and share the area with your customers in one link.

  • House hunting

    Put the center on your workplace or your kid’s school and see which towns are within a distance that works for you.

  • Day trips

    See which cities, parks and lakes are within reach before you decide where to go for the weekend.

  • Geography class

    Teach scale and area with something students can see: 100 mi around downtown Kansas City covers about the same as Maine (30,845 mi²).

100 mi around downtown Kansas City

A circle with a 100 mi radius centered on downtown Kansas City covers 31,414 mi²: about the same as Maine (30,845 mi²). Its edge is 628.3 mi long and it’s 200 mi across.

It reaches into three states (Kansas, Missouri and Nebraska) and 73 counties. A state or county counts as soon as the circle reaches into it, even if it doesn’t cover all of it.

How it’s calculated

Mapsfera draws the circle on the Earth itself: every point on the edge is the same real distance from the center, measured on the WGS84 ellipsoid, which is why it looks a little stretched toward the poles on the map. There are two ways to work out the area.

On a flat plane

A = π · r²

r is the radius. For 100 mi: π · 100² = 31,416 mi².

On a sphere

A = 2πR² (1 − cos(r/R))

R = 3,959 mi (6,371 km), the Earth’s mean radius. The angle r/R is in radians.

Mapsfera uses the sphere formula, because it matches the circle you see on the map. For 100 mi it gives 31,414 mi², almost the same as on a plane; the gap grows with the radius: at 500 mi, 784,355 mi² versus 785,398 mi² (0.1% less).

Common radii
Radius Perimeter Area
5 mi 31.4 mi 78.5 mi²
10 mi 62.8 mi 314.2 mi²
25 mi 157.1 mi 1,963.5 mi²
50 mi 314.2 mi 7,853.9 mi²
100 mi · this example 628.3 mi 31,414.3 mi²

Frequently asked questions

Is the radius measured in a straight line or by road?

In a straight line, “as the crow flies”. Driving distances are almost always longer: if what matters is how far you can drive in a set time, what you need is a drive time map.

Which states does a 100 mi radius around downtown Kansas City reach?

Three: Kansas, Missouri and Nebraska, and 73 counties in all. A state or county counts as soon as the circle reaches into it, even a little.

Can I draw several circles at once?

Yes, up to five. Tap “Add another circle” and pick another center and radius. Each circle has its own results and the link keeps all of them.

How do I save or share the circle?

Use “Copy link”: whoever opens it sees the same center, radius and units. To use it in other mapping software, download it as GeoJSON or KML (Google Earth); for a document or a slide, as a PNG.

Why doesn’t the circle look perfectly round?

Because the map uses the Mercator projection, which stretches things toward the north and south. The circle itself is right: every point on its edge is the same distance from the center on the ground.

Do I need to sign up or pay?

No. It’s free, it works in the browser on your phone or computer, and it doesn’t ask for an account.

Related tools

All tools
Distance between two points Measure the distance between any two places or points on the map, in miles or kilometers. Distance between cities Pick two US cities and get the distance between them, both in a straight line and by road. Distance between ZIP codes Enter two US ZIP codes to get the distance between them and see both areas on the map. Straight line vs driving distance Compare the as-the-crow-flies distance with the real driving distance and see how much the road adds.

Sources and method