How Many Blocks in a Mile?

Date: 11/24/2005 at 17:34:44
From: Diane
Subject: how many blocks in a mile

How many city blocks are there in a mile?  Some of my classmates are
saying 12 but I say 10.

Date: 11/24/2005 at 22:04:54
From: Doctor Wilko
Subject: Re: how many blocks in a mile

Hi Diane,

Thanks for writing to Dr. Math!  I've seen this question come to our
website several times and I've noticed that we don't cover it in our
archives.  That made me curious as to what the answer could be.

The key to answering your question is deciding just how big one block
is.  The bigger the block, the fewer of them are needed to make one
mile.  So the question really boils down to how big is a city block?

I'm no authority on the subject, so I decided to search the Internet
to see what I could find.  What I found was lots of different answers!
Here are some of them:

---------------------------------

A great article that gets into some history of roads and city blocks 
summarizes the answer in this line:

  "Each city block is just as big as it is. They aren't even all the 
same shape."

But the article goes on to say,

  "A city block would typically be 1/16 to 1/8 of a mile..."

See the full article at

  City Block
    http://c2.com/cgi/wiki?CityBlock 

---------------------------------

Here's another good historical perspective concerning Philadelphia. 

According to this article, Philadelphia was the first American city 
planned as a grid.  Today there are about 13 blocks to a mile in an 
old Philadelphia city block:

  Looking for Land Measurements - City Blocks.
    http://www.designcommunity.com/discussion/19066.html 

----------------------------------

According to Chicago's Transit Authority, in Chicago there are 8 
blocks to a mile:

  System Maps
    http://www.transitchicago.com/maps/systemmaps.html 

-----------------------------------

From www.nyctourist.com, they say,

  "...10 street blocks (east-west) are equal to 1 mile.  This rule 
does not apply, however, to parts of Greenwich and all of lower 
Manhattan."

  Getting Around New York City
    http://www.nyctourist.com/nycinfo_getaround.htm 

------------------------------------

Here's an article that says it is somewhere between 15 and 20 city 
blocks per mile:

  How Big is a City Block?
    http://www.land4ever.com/block.htm 

------------------------------------

Finally, probably one of the best pieces of advice for answering this 
question came from the folks at Math Central where they say:

  "I suggest that you call the appropriate office in the city where 
you live and ask your question there."

See the entire answer here:

  The Number of City Blocks in a Country Mile
    http://mathcentral.uregina.ca/QQ/database/QQ.09.99/hearst1.html 

------------------------------------

What I discovered in this short little tour across the Internet is 
that there is no one single answer to your question.  If you need to
know this about your community, there may be a city planning board or
someone who works with zoning issues in your city that can tell you
how your city was built and ultimately how many city blocks there are
to a mile in your town.  Thanks for the interesting question!

Does this help?  Please write back if you have further questions. :-)

- Doctor Wilko, The Math Forum
  http://mathforum.org/dr.math/