Condom Diameter

[AnonymousGuy]

I found reliable information saying that condom diameter is measured with the condom laying flat. So how would you calculate actual circumference given the condom was actually circular?

EDIT:Haha, I just realized what a stupid question this was xD I'd just multiply the diameter by 2... But I find it hard to believe that the Trojan Magnum XL has a circumference of about 5 inches at the head, and only about 4.3 inches around the body. That doesn't seem right. But if you take those numbers as circular diameter, then the body of an average condom calculates to more than 6 inches, which can't be right :S Anyone know anything?

[Andelicious]

The circumference is equal to pi times the diameter (C= π x D), so all you have to do is get a calculator and multiply the width they're giving for the condom by pi.

[Andelicious]

I also just realized you made this exact same post already three days ago....

[AnonymousGuy]

No, this post is about flat measurement. What I've realised, IIRC, is that the measurements they give for width are side to side laying flat, thereby making the circumference equal to twice the width given. However, using both the methods, pi and doubling the diameter, give odd results, and I thought I'd bring it up in a new discussion.

[Andelicious]

That's what I'm saying, the circumference isn't just double the width (diameter). Here's (http://en.wikipedia.org/wiki/Circumference) the wiki article about it. Pi times the diameter is how to calculate it.

[AnonymousGuy]

Yes, but what I'm saying, is that IF (again, IIRC, it's this way) they measure with the condom lying flat, and not inflated to a near perfect circle, then the circumference is going to equal ~2(diameter).
The way you mention (Pi * diameter) only works if the diameter is measured when the condom is inflated into a cylinder.
When the condom is lying flat, it's basically just two pieces of half-oval latex lying on top of each other. To get the circumference of that, you'd have to measure the distance around it, which would be almost equivalent to just adding the width of one of the flat sides, to the width of the other.
If it's inflated, pi applies because it's a circle, and the diameter of the circle could then be used to calculate the circumference.
However, what I've read is that condoms are measured lying flat, not inflated, so the former method applies.
The reason I've brought this up, is because of some calculations I did involving the circumference of an average condom, and one of greater width.
For example, Condom Depot lists the average condom as having a width of 2 inches. When applied to the "flat" formula, that comes out to 4 inches, which is perfectly reasonable, knowing that the average penis has a girth of about 5 inches. That'd allow for the condom to fit tightly, and not slip. When you apply the "round" model, you'd come out with a condom girth of ~6.2 inches, which obviously is too large for the average penis. This concludes me to believe that the condoms are measured flat.
What really strikes me as odd, however, is that the measurements for the Trojan Magnum XL, which is supposed to be larger in girth for larger penises, is, using the flat calculation, only 4.28 inches at the shaft, and 5.4 inches at the head, as well as 4 inches at the base. Of course, using the pi calculation, the difference between an average condom and the Magnum XL is more noticeable, but with the flat calculation, it's almost negligible, besides the head.
Any thoughts?

[Andelicious]

What really strikes me as odd, however, is that the measurements for the Trojan Magnum XL, which is supposed to be larger in girth for larger penises, is, using the flat calculation, only 4.28 inches at the shaft, and 5.4 inches at the head, as well as 4 inches at the base. Of course, using the pi calculation, the difference between an average condom and the Magnum XL is more noticeable, but with the flat calculation, it's almost negligible, besides the head.

The reason for the large difference in your numbers is because your "flat" method doesn't make any sense. There's absolutely no reason to try and come up with some weird new way of calculating the width of a condom. Condoms are meant to cover the cylindrical shape of a penis, which is why you would calculate the diameter in that way. It's incredibly simple, all you have to do to find out what brand would fit you is measure your girth and divide that number by pi. That's it. Or better yet, just buy some three packs of different condoms at a grocery store or gas station and try them on. Problem solved.

[AnonymousGuy]

I'm assuming you meant to multiply by pi. In the case of an inflated condom, which WOULD be cylindrical, you would in fact multiply the diameter by pi, to get circumference. HOWEVER, if the condom is being measured lying flat, it's circumference (and surface area) become little more than two flat lines on top of each other, necessitating a change in method of measurement. Pi doesn't apply to non-cylindrical objects, such as a flattened condom. SO, I'm assuming, that the width given in the measurements for the condom are distance across left-to-right, laying flat.

EDIT: Rereading your post, I see we're thinking about two different things here. You've seemed to move over to talk about calculating diameter, give a certain girth. I'm talking about calculating girth, given a certain diameter. Of course, the argument still remains that the measurement of diameter on a condom is going to be different if they are lying flat, or cylindrical.

[darkwoon]

Condom girth seems to be given, most of the time, as their width when lying flat. It means that the circumference (girth) is 2x the given value, and the diameter is thus given by "value x 2 / pi".

I suppose they give the "width as flat" measure because for most people, it is simpler to multiply a value by 2 than by 3.14159 ;).

[Alex_16]

take the width of it and multiply it by 3.14 .. AKA ..Pi (rounded of course)

[Andelicious]

You've seemed to move over to talk about calculating diameter, give a certain girth. I'm talking about calculating girth, given a certain diameter.

Either way, you can figure out what you're looking for. Circumference = pi x diameter, which can easily be rearranged to find the diameter. Diameter = circumference / pi

If you want to know what size condom to purchase, all you need to do is measure your girth and divide it by pi, which will give you a number to compare to the width sizes on that website.


Of course, the argument still remains that the measurement of diameter on a condom is going to be different if they are lying flat, or cylindrical.

Unless it's inflated there isn't even a diameter to begin with, because a diameter (http://en.wikipedia.org/wiki/Diameter) is defined as "any straight line segment that passes through the center of (a) circle and whose endpoints are on the circle." What you're suggesting is an inaccurate way of determining the true diameter of a condom.