Guessing a hat size if someone only knows the inside diameter?

[carldelo]

Alternate method - measure the OUTSIDE circumference

It's easy to measure the outside circumference of a hat using a soft tape. From elementary geometry, it's easy to show that the inside circumference will be less by 2*Pi*t, where t is the thickness of the hat itself. The thickness includes the sweatband, the felt, the ribbon and the bow. This is great if you could measure the thickness, but that's not easy.

However, I just did a test with 8 of my hats, and the results seem pretty useful --- the term 2*Pi*t appears to be almost exactly 1". I wear a size 7-3/4, and my head is 24-3/8" in circumference. Measuring the outside circumference of 8 hats gives the following results:

• The three hats that fit the best all had outside circumference of 25-3/8". Subtracting 1" gives 24-3/8", my size.

• One hat that fits a bit tight had outside circumference 25-1/4". Subtracting 1" gives 1/8" less than my size.

• Two hats that fit slightly loose had outside circumference 25-1/2". Subtracting 1" gives 1/8" oversize.

• One hat has outside circumference 25-5/8", if fits slightly loose with 1/8" foam strips behind the band.

• My old straw that I bought one size too small has outside diameter 24-7/8", subtracting 1" and dividing by Pi gives a size slightly less than 7-5/8, as it has shrunk over the years.

FWIW, 5 of the hats are modern Stetsons, 2 are Akubra polystraws and 1 is a vintage Milan straw.

If one could measure the outside of a hat and just subtract 1" to find the internal circumference, that would be very useful. I'd be very interested to see the results from others who can do the same measurements with a range of hats. The results should depend on hat thickness, and I have a limited sample to work with. Perhaps for thicker felts, one could subtract a bit more, 1-1/8".

As Art points out, however, circumference itself won't guarantee a good fit. But it can rule out a hat that's clearly the wrong size.

 

[carldelo]

"Faint hat never won fair lady."

I believe on this measuring device, the measurement that is quoted as "hat" is the inside circumference of the felt blank, before the sweat band is sewn in. I'm remembering that from a discussion years ago.

EDIT - see The Dane's comment below - I think he has it right.

 

[TheDane]

In my opinion the best way of determining a true size is to find the right band block that slips into the hat nicely, then measuring the block. Measuring circumference with only a soft tape is anything BUT accurate. Whether the hat fits you is another subject because of head shape.

Absolutely, but completely unrealistic when dealing on eBay. The head circumference (in the prefered "hat-line") is what gives the hat-size. To meassure that on a belling sweat is like measuring the length of a piece of elastic. To get the size from the hat's length and width is just as unrealistic. One can not expect that an eBay-seller has one's personalized band block at hand - and even the best custom hatters' conformer measurements are not always correct in the first try (at least not when performed by the purchaser).

In my view we are back to the choise between: "Stay away from all surprizes, ie. anything but of-the-rack hats" and "Get used to life's small surprizes and squeeze all possible enjoyments out of life". At the end of the day, it's just a hat - the neatly arranged remains of a rodent-carcass - so I would anytime choose to take the chance

 

[TheDane]

I believe on this measuring device, the measurement that is quoted as "hat" is the inside circumference of the felt blank, before the sweat band is sewn in. I'm remembering that from a discussion years ago.

More likely the actual size (inside circumference) and the outer circumference of the finished hat. The sweatband does not take up a whole inch in circumference. A 7 1/8 block fits almost perfectly a 7 1/4 hat with sweatband. I think the two sizes are both outer circumferences ... one of the head and the other of the hat. That would at least fit better with the measurements given on the ruler

 

[John Galt]

More likely the actual size (inside circumference) and the outer circumference of the finished hat. The sweatband does not take up a whole inch in circumference. A 7 1/8 block fits almost perfectly a 7 1/4 hat with sweatband. I think the two sizes are both outer circumferences ... one of the head and the other of the hat. That would at least fit better with the measurements given on the ruler

This is consistent with the anecdotal evidence above. Now all we need is a hatter that was working between 1874 to 1897 to confirm...


"Faint hat never won fair lady."

 

[HudsonHawk]

Actually, your strategy is perfect if all you want is fit. In fact, this is what everyone used to do back in the olden days of yore... they'd go to a hat store and buy one that fits right.

We'll fit is not the "only" thing I want in a hat, but it's certainly by far the most important. In fact it's an absolute necessity. To me, a hat is just too personal of a purchase to guess.

 

[mayserwegener]

Actually, your strategy is perfect if all you want is fit. In fact, this is what everyone used to do back in the olden days of yore... they'd go to a hat store and buy one that fits right.

But often times they (soft and stiff felts) would be tweaked to fit.

 

[DougC]

can't you just take the inside measurement of the hat and divide by Pi to get the US hat size? Or you could ask the seller to measure the circumference of the band in centimeters give you the metric size? seems pretty easy to figure out...and another stolen idea from a thread long-since read.

 

[carldelo]

can't you just take the inside measurement of the hat and divide by Pi to get the US hat size? Or you could ask the seller to measure the circumference of the band in centimeters give you the metric size? seems pretty easy to figure out...and another stolen idea from a thread long-since read.

This has been mentioned above and elsewhere, many times. The issue is the difficulty of correctly measuring an inside circumference. Give it a try if it seems easy to you - it definitely is not easy, and basically does not work.

A version of Art's hat block method is fitting a regular old hat jack into the hat, then measuring it's circumference. But this is quite sensitive to how tightly (or not) one adjusts the hat jack. Plus, hat jacks often have tapered sides, so there is the problem of keeping the tape at the correct height on the jack while measuring.

I've also traced around the sweat band while a hat is sitting on one of the conical cardboard hat stands one finds in shipping cases sometimes. Measuring a little below the traced line gives an OK estimate of the circumference.

I've tried all of these methods, and the one that gives the best indication of fit is the one I mentioned above: Measure the outside circumference, then subtract one inch. I'm still waiting to see if anyone else will try it. I'm an experimentalist, and am looking for more data.

 

[carldelo]

More likely the actual size (inside circumference) and the outer circumference of the finished hat. The sweatband does not take up a whole inch in circumference. A 7 1/8 block fits almost perfectly a 7 1/4 hat with sweatband. I think the two sizes are both outer circumferences ... one of the head and the other of the hat. That would at least fit better with the measurements given on the ruler

Yep, I think that makes perfect sense.

 

[galopede]

Easiest way I have found to measure the inside circumference quite accurately is to use masking tape. Don't know if that's what it is called stateside. It's the low stick paper type tape you put around windows etc before painting. Just stick it around the sweatband and mark where the ends meet, unpeel and measure flat.

Simple

 

[bendingoak]

Easiest way I have found to measure the inside circumference quite accurately is to use masking tape. Don't know if that's what it is called stateside. It's the low stick paper type tape you put around windows etc before painting. Just stick it around the sweatband and mark where the ends meet, unpeel and measure flat.



Simple

You beat me to it. I was just about to post this but was waiting to take some pics to make my point.

 

[John Galt]

Check out the difference between these two very old hat rulers:

http://www.thefedoralounge.com/showpost.php?p=1708509


"Faint hat never won fair lady."

 

[bombin]

If a seller suggests that the length/width measurement of a hat is 8" x 6", would that be likely to be a hat with something like a 22" circumference? (I need something closer to 23", and some I'm thinking this hat must be too small, even if I wanted to stretch it a bit.) Or is it possible it's actually a larger circumference?

 

[Joao Encarnado]

A 8"x6" hat is a size 7 Long Oval.
It is possible to stretch it 1 size without replacing anything (depending on sweatband condition) but it will not be a 1 day work...
A hatter will be able to stretch it several sizes.

 

[bombin]

Thanks Joao. My understanding is that anything beyond a 1 size stretch will start to significantly alter the hat look (by eating the brim or crown). No?

 

[gtdean48]

Thanks Joao. My understanding is that anything beyond a 1 size stretch will start to significantly alter the hat look (by eating the brim or crown). No?

Stretching wonks out the brim flanging but usually acceptable for just 1 size or less. After that, it looks to out of shape. Reblocking to go up sizes typically eats brim width....

 

[bombin]

Right, I think I'll pass on this one then.

 

[Edward]

If it's a rare enough hat at a price low enough that you can cover your costs if it dosn'tg work out, and you think there's a reasonably high chance it will fit, then it might be worth a shot. Otherwise, though - no, I wouldn't risk it.

Very well put, fedoracentric. Another variable is asking a seller for any of these measurements and trusting they know how to do it, read the tape properly, etc. I have bought a number of hats online where the measurements were given only to find them to be incorrect when I received the hat.

Never assume that eBay sellers can measure properly - or even understand how sizing works. The number of eBay sellers in the UK that simply cannot comprehend a jacket measuring 42" round the chest doesn't mean it will fit a person with a size 42" chest is unbelievable. Might ex plain all those hipsters wearing everything two or three sizes too small, though...