Comments on: iPad Tech Specs – Dimensions

By: Paul E Musselman

Paul E Musselman — Sun, 01 May 2011 16:39:36 +0000

When I was in college there were -2- metric systems: CGS and MKS. The basic units were:
CGS- Centimeter-Gram-Second
MKS- Meter-Kilogram-Second
At the time (1970s) MKS was the ‘preferred’ system for physics problems.
–Paul E Musselman

By: Maybury

Maybury — Tue, 19 Apr 2011 18:20:25 +0000

I know this was over a year ago but I googled iPad dimensions and saw your comment, I was horrified! no wonder some have a problem with metric when some don’t use it the way it was designed, Apple got it right, centimeters are officially part of SI units but in the same way as no-one uses heptometers (or decimeters, centigrams or any other intermediate unit) in engineering, It is based on multiples of 1000, k- kilo, M- Mega, m- mili, n- nano etc.
to use centimeters is not “wrong” but to correct something which is better with something that is worse is unhelpful.

By: patrickj

patrickj — Tue, 09 Feb 2010 22:37:02 +0000

Ahhh, good I think :)

By: ianf

ianf — Tue, 09 Feb 2010 08:54:50 +0000

Semantic corrections: the 63:37% figure above is
of screen-to-bezel ratio; the screen is the same
width as an A5 paper sheet, while being 1 cm
shorter (envelope for that format is C5, not A5).

Other than that, there is an interesting difference
vs. pixel- and physical screen sizes of iPhone/ iPod
Touch. Both handhelds sport a screen of 480×320
pixels, but of higher density, 163 dpi to iPad's 132.
iPhone's screen is 5.78 square inches with 153600
pixels. When compared to iPad's own [1024 x 768=]
786432 pixels over 45 square inches we find that,

while pixelwise iPad's screen is [786432 / 153600=]
5.12 times larger, in physical terms it is [45 / 5.78=]
7.8, or ALMOST 8 TIMES LARGER than iPhone's own.

So imagine 8 Touch-screens [sans bezel] in portrait
mode arranged in two rows of four, then the entire
assembly shifted 90 degrees to portrait again – and
there you have it, a mental picture of how big the
iPad's screen will feel in April [rhyme coincidential].

As an aside, were iPad's 1024×768 px screen of the
same density as the iPhone, 163 dpi, it would either
have to shrink in physical size to [[1024/163=] 6.28
x [768/163=] 4.71]= 29.6 square inches; 191 cm^2
[vs. current 45 sq. in./ 291 cm^2], –OR–, if present
[7.75 in. x 5.81 in.]= 45 sq. in. screen size be kept,
increase pixel count to [5.81*163=] 947 px wide and
[7.75*163=] 1263 px high; 1196336 px square total.

This would give a pixel count that's either 152%
bigger, or 66% smaller depending on whether present
figure [786432] be treated as default or not.

How's that for a unholy-Kabbalistic approach to iPad's
numerology? ;-))

By: patrickj

patrickj — Tue, 09 Feb 2010 00:23:45 +0000

Apple's page does actually list the display as 9.7 inches diagonal, and I believe that's also long been the standard for stating computer screen sizes – as in when someone says they have a 15 inch monitor, that's a diagonal measurement as well.

By: ianf

ianf — Tue, 09 Feb 2010 00:17:23 +0000

Here are few other iPad-metrics, that Apple in its eternal
& bottomless marketing wisdom has deemed unimportant
to publicize: ACTUAL SIZE OF THE SCREEN ITSELF.

Disclosed height and width figures are of the iPad, not
its coniderably smaller viewable area. Dividing known
screen width of 768 pixels by claimed density of 132dpi
[dots per inch; dots=pixels] gives physical 5.8181818
inch-screen width; 5.8" rounded off, or [5.8*2.54=] 14.8
cm, also rounded off. Similarly, 1024 pixels divided by
132dpi leads to 7.75 inches, or 19.7 cm screen height.

iPad's LCD screen is thus 7.75 by 5.8in wide
(or rounded off: 20 x 15 cm). That is somewhat
smaller than an European A5 envelope.

Area-wise this in turn gives total 71.4 square in., or
460 cm^2 for the iPad; vs. 45.1 sq. inches; or 291
cm^2 for the display. This represents a 63:37% ratio
of unit:screen real estate (the 37% makes up the
bezel around it.)

Finally, unless my calculations are way off base
(could be), diagonally the screen is 9.69 inches,
i.e. very close to stated 9.7 in, or 24.4 in good-
olé-centimeters.

[diagonal = length of right-angled triangle's
hypotenuse is the square root of added
squares of the other two sides]

By: patrickj

patrickj — Mon, 08 Feb 2010 21:45:12 +0000

I remember a TV series which was called 'Bergerac' I think, which was set in the Channel Islands. Still can't think in stones, always in pounds and so on. Thanks for the tips, but I'll stick with inches, yards, and all the yankee stuff for now. :)

By: patrickj

patrickj — Mon, 08 Feb 2010 20:20:25 +0000

Thanks for the useful translations. I have to admit that I never fully got to grip with the metric system either, even after a dozen years in the UK :)

By: ianf

ianf — Mon, 08 Feb 2010 19:49:57 +0000

I realize you copied it off Apple's specs page, so it's their bailiwick, but it only goes to prove that the mighty Californian company has yet to come to terms with the metric system. No European in his right mind would ever express those measures in terms of fractional millimeters – over 10 mm size we use "centimeters." And weight of that magnitude is best stated in grams (1000g = 1kg).

Here are the colloquially-correct metric values:

Height: 9.56 inches (24.3 cm)
Width: 7.47 inches (19 cm = 189.7 mm rounded off to)
Depth: 0.5 inch (1.3 cm – or 1.34 cm if one wanted to be anal; observe that 0.5 inch = 12.7 mm or 1.27 cm otherwise)
Weight: 1.5 pounds (680 g) Wi-Fi model;
1.6 pounds (730 g) Wi-Fi + 3G model