What the fuck does a 10.1 inch screen really mean? We did the math so you don't have to.

With so many choices out there, choosing a tablet for reading your digital comics is a major pain in the ass. We all know the dimensions of a standard comic book page - 6.625" by 10.25" - but what are the dimensions of a 9.7" iPad screen, a 7" Google Nexus screen, a 10.1" Galaxy Tab, or an 8.9" Kindle Fire HD? The information isn't readily available. The measurement posted in most product descriptions is the diagonal size of the screen, but that doesn't translate easily to width and height dimensions. And, without those dimensions, it is nearly impossible to compare these tablets for the purpose of reading digital comics.

I have read digital comics on a 7" original Kindle Fire for over a year now. I like it, but to really see the panels, I either need to use a guided view, like most apps offer, or view the page in landscape mode, scrolling down to read. I would prefer to hold the tablet in portrait mode, fit the entire page on the screen at maximum size, and read it like I would a paper page, allowing my eyes to scan the page naturally instead of forcing it through scrolling. However, on a 7" screen, it's just barely big enough to do that.

So what would be the best upgrade? An iPad is 9.7" diagonally, and a Toshiba Thrive is 10.1", but how does that translate to the comic book page when you consider that the iPad is closer to a square, while a Thrive is a thin rectangle. We can assume that a 10.1" screen is bigger than a 9.7" screen, but if the 10.1" screen can constrains the width of the comic page to the point where you have inches of wasted space above and below the image, it's not going to make our comic appear any larger.

So how do you translate a diagonal measurement to width and height, something that we can all understand and use to make an informed decision? With the Pythagorean Theorem: a^{2} + b^{2} = c^{2}.

Now, your old pal Jude Terror is no math wiz, but I do have what I hope is a capacity to understand and execute it with a little bit of reading. So with that in mind, let's explore the wonderful world of Algebra, see what I can pass on to you from my own investigations into this issue, and, at the end, provide a helpful chart that will make an easy reference for anyone looking to make an informed tablet buying decision (skip to the end for the chart if that's all you're looking for).

From Wikipedia:

In any right-angled triangle, the area of the square whose side is the hypotenuse (the side opposite the right angle) is equal to the sum of the areas of the squares whose sides are the two legs (the two sides that meet at a right angle).

Wikipedia provides a nice illustration as well:

So, what does that mean? We know the value of c. It is the diagonal measurement of the screen (in the case of the iPad, 9.7"). We can also find the aspect ratio of the screen in most product descriptions. In the case of the iPad, the aspect ration is 4:3. We can express this as a formula: W=(4/3)H.

Now let's plug the values we know into the Pythagorean Theorem formula: (4/3H)^{2} + H^{2} = 9.7^{2}. Now we can solve it, using what little algebra we remember from high school. This isn't going to be pretty, but it will get us where we need to go:

( 4 / 3 * H )^{2} + H^{2} = 9.7^{2}

( 4 / 3 * H )^{2} + H^{2} = 94.09

( 16 / 9 ) * H^{2} + ( 9 / 9 ) * H^{2} = 94.09

H^{2} = 94.9 * ( 9 / 25 )

H^{2} = 34.164

H = 5.84

So our height in this case is 5.8". W=4/3H, so our height is 7.8". So how does that relate to a comic book page? A comic book page's aspect ratio is 10.25:6.625, so on a 4:3 screen, it will be constrained by the longer edge, rather than the shorter (the opposite is true on a 16:10 screen). So if we are reducing the comic book page to a height of 7.8" to fit in the long edge of the screen, we can use this formula to find the width: x / 7.8 = 6.625 / 10.25.

x / 7.8 = 6.625 / 10.25

x / 7.8 = .646

x = .646 * 7.8

x = 5

So an iPad can display a comic book page at the maximum size of 5"x7.8". Not too shabby.

Now, we can apply the formulas above to any of our other screens, and I encourage you to do it, but just in case you're going, "wha huh?!" I've taken the liberty of doing it for you for several popular screen sizes and aspect ratios. I have taken the liberty of rounding at several points in our equations to make the math easier to explain and digest, so consider that there is a margin of error of something like .1" on all these measurements.

A 9.7" screen with a 4:3 aspect ratio (like an iPad) is 5.8" x 7.8", and can display a comic book page at a maximum size of 5" x 7.8".

A 8.9" screen with a 16:10 aspect ratio (like a Kindle Fire HD 8.9") is 4.7" by 7.5" and can display a comic book page at a maximum size of 4.7" by 7.3".

A 10.1" screen with a 16:10 aspect ratio (many 10.1" Android tablets) is 5.4" by 8.6" and can display a comic book page at a maximum size of 5.4" by 8.4".

A 10.1" screen with a 16:9 aspect ratio (many other 10.1" Android tablets) is 5" x 8.8" and can display a comic book page at a maximum size of 5" by 7.7".

A 7" screen with a 16:10 aspect ratio (like most 7" Android tablets) is 3.5" by 6" and can display a comic book page at a maximum size of 3.5" by 5.4".

A 7" screen with a 4:3 aspect ratio (like the iPad Mini) is 4.2" x 5.6" and can display a comic book page at a maximum size of 3.6" by 5.6".

So there you have it. If you're looking for a tablet that can display a full comic book page at the maximum possible size, a 10.1" screen with a 16:10 aspect ratio is what you're looking for.

If you want to know what the maximum height of your page will be if displayed at the maximum width of the screen, you can divide the width by .646. If you want to know the maximum width of your page if displayed at the maximum height of the screen, you can multiply the height by .646.

Of course, there are other aspects to take into consideration, such as the screen resolution, which might affect how crisp the image appears, as well as the quality of the display itself, which could affect how well it displays the colors and the general quality of the reading experience. But that's an article for another day.

For now, here's an easy to read table. All you need to know is the diagonal screen size and the aspect ratio of the tablet you're looking to buy, and you can see how big the screen really is, in useful screen dimensions, width and height, and how big of a comic book page you can squeeze onto there.

Screen Dimensions and Comic Book Page Display Size on Various Tablets Tablet | Diagonal Screen Size | Aspect Ratio | Screen Width | Screen Height | Maximum Full Comic Page Width | Maximum Full Comic Page Height |

Kindle Fire, Nexus 7, etc. | 7" | 16:10 | 3.5" | 6.0" | 3.5" | 5.4" |

Kindle Fire HD 8.9" | 8.9" | 16:10 | 4.7" | 7.5' | 4.7" | 7.3" |

iPad Mini | 7" | 4:3 | 4.2" | 5.6" | 3.6" | 5.6" |

iPad | 9.7" | 4:3 | 5.8" | 7.8" | 5.0" | 7.8" |

Toshiba Thrive and other 10.1" Androids | 10.1" | 16:10 | 5.4" | 8.6" | 5.4" | 8.4" |

Galaxy Tab and other 10.1" Androids | 10.1" | 16:9 | 5" | 8.8" | 5.0" | 7.7" |

Did I get everything right? If you're a math wizard and have anything to add, please post in the comments or on our forum and I'll add it to the article. We are making the world a better place here, people. We're making it a better place for people who just want to know how large they can display a comic book page (without scrolling) on their handheld digital comic reader.

**UPDATE #1:** Outhouse writer sdsichero pointed out that the comic book size we are discussing here is the modern American comic book size. Dimensions were slightly different in the Silver Age and Golden Age, and are different for Manga and possibly European comics. However, you can use the methods above to find the maximum page size on your tablet as long as you know the dimensions of the type of page you want to display.

Written or Contributed by Jude Terror

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