Thanks Michael. Your explanation helped identify a bug (now fixed).

I tried concentric circles from Allen, TX ("33.103186,-96.670551") with 100 mile increments -- "33.103186,-96.670551", 1, 2, orange "33.103186,-96.670551", 100, 101, blue "33.103186,-96.670551", 200, 201, red "33.103186,-96.670551", 300, 301, green "33.103186,-96.670551", 400, 401, yellow "33.103186,-96.670551", 500, 501, blue "33.103186,-96.670551", 600, 601, red "33.103186,-96.670551", 700, 701, green "33.103186,-96.670551", 800, 801, yellow I am trying to see how far it is to Big Bend national park. Google Maps shows this to be about 476.27 miles (766.48 km). The concentric circles tool puts Big Bend between 700 and 800 miles -- I think it is scaled to km by mistake. I tried the tool set to km with the radio button, but the circles shrank to about 60%. It seems like the default miles measurement is set to km length and the km measurement is 0.6 of that.

This is too confusing and is harder than it needs to be. A very simple line from Point A to point B for distance would've been very easy to use. I will search for a different program that will also allow me to draw a circle with a 3 mile radius and place it where I want it. This program I don't like.

Worked it out - errant quotation mark on first line

"51.1374899,11.6904702%u2033,0,4,blue "51.2580935,9.4057882",0,15,red This worked on the first try, but now I only get the red circle!? And the textbox is clearing on click so like the last comment shown - making edits is a pain in the proverbial ;)

Allan, you can input each circle on a new line in the text box. So by processing 2 at the same time, this should do what you need.

In the past, I found optimal routes between two distance locations in different states by drawing concentric circles of equal radii, one at point A and the other at point B (both specified as a set of GPS coordinates), using this excellent tool. Today, I find the concentric circle I drew at point A disappears when I enter the command to draw the concentric circle at point B. I can't remember what I did in the past to make both concentric circles visible simultaneously. (Typing "hold on" after drawing the first concentric circle did not work.)

Thanks for the suggestion Antony.

Thank you for a useful utility. As an enhancement it would be useful to be able to specify an interval between concentric circles so that a set of n concentric circles can be drawn.

"Prairie Village, KS",100,399,blue "Prairie Village, KS",400,401,red

It would be great for math problems, if I could figure out how to use it.

Jeff, it doesn't really take in to account drive time. More of a line of sight circle. You may be better looking at : How Far Can I Travel.

How close are concentric circles and realistic drive times? (NJ)

Steven, an option would be to use Find ZIP Codes Inside a Radius and use it twice then find the ZIPs common to both radius.

Would it be possible to generate a list of ZIP codes inside an area where two circles overlap?

Hi, you can use https://www.freemaptools.com/how-far-is-it-between.htm to find the distance between the places. So 130km between NTY and Philadelphia. The make the circles on this page half that or a bit more to get some overlap. So, 80km radius gives:
"Philadelphia, PA, United States",0,80,red
"New York, NY, United States",0,80,blue

I want to be able to make circles around 2 points where I click so that the concentric circles meetup. Say Where are the halfway points between Philadelphia and NY City?

"san ramon, ca",5,5,blue "san ramon, ca",10,10,blue "san ramon, ca",15,15,blue "san ramon, ca",20,20,blue "san ramon, ca",25,25,blue

Stephan, you can now export to KML format

Stephan, you comment has been noted, understood and something is in the pipeline.