Paper Sizes

ISO Paper Sizes

The ISO family of paper is commonly used in Europe. It uses a single aspect ratio for all sizes in its range. Most paper is in the A Series. It is defined by ISO 216.

A Series

A0 is one square meter, with the sides forming a ratio of 1:14142 (one to the square root of two). Each smaller size of paper is half of its predecessor, divided on the longer edge, retaining this ratio. The short side of one size becomes the long size of the next smaller one. This allows for consistent steps up and down. Enlarging or reducing on a copier makes for consistent steps with no blank space.

While it’s less common in the United States, I prefer it, if only for the geeky logic behind it. I also find that ISO paper sizes are what is typical for the most fountain pen friendly paper.

Size Inches Millimeters Notes
A0 33.125 x 46.8125 841 x 1188 The origin. One square meter
A1 23.375 x 33.125 594 x 841  
A2 16.5 x 23.375 420 x 594  
A3 11.75 x 16.5 297 x 420 Close match to “tabloid” paper
A4 8.25 x 11.75 210 x 297 Close analog to “letter.” A bit narrower and taller.
A5 5.875 x 8.25 148 x 210 “Junior” size paper. Most journals are this size.
A6 4.125 x 5.875 105 x 148 Good pocket notebook size
A7 2.9375 x 4.125 74 x 105 A good, if smaller, notebook size
A8 2.0625 x 2.9375 52 x 74 ISO-sized business card

Hypothetically, you can keep halving the paper until you reach some atomic size.

B Series

The B series is used to fill some gaps in the A series. It uses the same ratio, but based on geometric mean of two a sizes. It has the same It’s used to fill gaps between sizes of A. It’s less common, but does come up for some stationary.

Size Inches Millimeters Notes
B0 1000 x 1414 39.4 x 55.7  
B1 707 x 1000 27.8 x 39.4  
B2 500 x 707 19.7 x 27.8  
B3 353 x 500 13.9 x 19.7  
B4 250 x 353 9.8 x 13.9  
B5 176 x 250 6.9 x 9.8 Books, some journals
B6 125 x 176 4.9 x 6.9 Books, some journals
B7 88 x 125 3.5 x 4.9 Passports ISO 7810, ID-3
B8 62 x 88 2.4 x 3.5 Playing cards
B9 44 x 62 1.7 x 2.4  
B10 31 x 44 1.2 x 1.7  

C Series

The C series is the geometric mean between the A and B series of the same number. It is used for envelopes. C4 is a bit larger than A4, and can fit a sheet unfolded. A C5 envelope can hold an A4 sheet folded in half, and so forth.

Size Inches Millimeters Notes
C0 36.1 x 5.11 917 x 129.7  
C1 25.51 x 36.1 648 x 917  
C2 18.03 x 25.51 458 x 648  
C3 12.76 x 18.03 324 x 458  
C4 9.02 x 12.76 229 x 324  
C5 6.42 x 9.02 163 x 229  
C6 4.49 x 6.38 114 x 162  
C7 3.19 x 4.49 81 x 114  
C8 2.24 x 3.19 57 x 81  
C9 1.57 x 2.24 40 x 57  
C10 1.1 x 1.57 28 x 40  

North American Paper Sizes

Unlike the ISO standards, the North American sizes have no real rhyme or reason. Rather, they are based on a quixotic choice made by paper makers a long time ago. Generally, you will encounter Letter size, with most “journals,” like Moleskine are roughly half-letter sized.

Size Inches Millimeters Notes
Letter 8.5 x 11. 215.9 x 279.4  
Legal 8.5 x 14. 215.9 x 355.6  
Tabloid/Ledger 11. x 17. 279.4 x 431.8  
Junior Legal 5. x 8. 127. x 23.2  
Half-Letter 5.5 x 8.5 139.7 x 215.9  
Government Letter 8. x 1.5 23.2 x 266.7 Perscribed by Hoover; Reagan went back to “normal” letter.
Executive 7.25 x 1.5 184.15 x 266.7  
Business Card 3.5 x 2. 88.9 x 5.8  

Other Sizes

This covered the most common, general purpose paper sizes. There are some that are unique to different countries, or are proprietary to a specific offering of a planner.

What Do I Use?

In an ideal world, I’d use ISO series exclusively. The logical progression appeals to me, even if I don’t do a lot of reducing or enlarging. As a baseline, the most fountain pen-friendly paper tends to come in ISO series. For writing, I buy A4 and A5 pads, and favor A5 journals. These pads are either A4 before being stapled together (so the page torn out is slightly shorter than A4), or made to give a full A4 page when removed.

However, I live in North America, so the most common sizes of paper are letter and legal. This means most binder and notebook parts (covers, dividers, etc.) are built around this format (typically letter), as it most paper for printers. I have to live in that world.

As a consequence, my personal notebook, based on a combination of Levenger Circa and Staples Arc, is a hybrid. The main parts are North American sized, and a fair amount of things get added that are letter size from my printer. However, for the actual fill, I harvest paper from A4 pad. Often, I need to trim the paper so it fits in with the rest of the notebook.

All of this excludes some of the random pads and paper I have floating around from various give-aways and samples. These tend to be either half-letter or A5.

I’m probably going to incorporate a version of this into the reference section on my stash. But some recent discussion on Facebook, I though it was worth posting on my blog as well.