Converting Q (Kyu) and Points: How Many pt Is 13 Q? How Many Q Is 10 pt? Font Size Units (Q, H, pt, Gōsū, px, mm) with Tables, Leading and Type Area Calculations

The short answer: 13 Q is about 9.21 pt, and 10 pt is about 14.11 Q

Q (kyu) and points (pt) are both units of length used for font sizes. One Q is exactly 0.25 mm, and the point used in DTP is 1/72 inch, which is 25.4 ÷ 72 = about 0.3528 mm. Since the only difference is the length of one unit, you can always convert between them by going through millimetres.

For mental math, it is enough to remember “Q is 1.4 times pt, and pt is 0.7 times Q”. For 9 pt, 9 × 1.4 = 12.6, so about 13 Q (exactly 12.7 Q); for 13 Q, 13 × 0.7 = 9.1, so about 9 pt (exactly 9.21 pt). If you also remember “4 Q = 1 mm”, “20 Q = 5 mm” and “40 Q = 1 cm”, you can see the real size from a Q value straight away.

How many font size units are there? Q, H, pt, gōsū, px and mm

In Japanese printing and design, at least six units are used for font sizes: Q and H from the phototypesetting era, gōsū from the letterpress era, DTP points, web px, and millimetres. All of them are lengths, so lining up how many millimetres one unit is makes the relationships clear.

The “Q” of kyu stands for quarter: one Q is a quarter of a millimetre. H (ha, literally “teeth”) is said to come from the gear mechanism that advanced the photographic paper in phototypesetting machines, and it is the same 0.25 mm as Q. Because 4 Q make exactly 1 mm, the unit fits well with Japanese print work, where dimensions are thought of in millimetres, and Q and H are still widely used in typesetting specifications for books and magazines.

Points, on the other hand, originally had different lengths depending on the country and era. The point used on today's computers is the DTP point (PostScript point), exactly 1/72 inch. It differs by about 0.39% from the American point of the metal-type era (the JIS point, 0.3514 mm); at 72 pt, that is 25.4 mm versus about 25.3 mm. The Didot point used for European type (about 0.376 mm) is larger still, so when you read “pt” in an old document, check which point it means.

Q ⇔ point conversion tables (7–100 Q and 6–72 pt)

This table converts Q sizes common in phototypesetting and DTP into points, mm and CSS px. The px value is the size on screen at 100% zoom. “Nearest gōsū” is the Japanese gōsū size whose point value is closest.

The reverse table looks up Q from points. Use it to compare a size chosen in Illustrator or Word with a manuscript specified in Q.

Points and Q do not divide evenly into each other, so you get decimals such as 9 pt = 12.7 Q. If you need the exact specified size, the reliable way is to set your app to the same unit. In InDesign you can set type size to Q and leading to H under Preferences > Units & Increments, and in Illustrator you can switch the type unit to Q under Preferences > Units.

Japanese gōsū and Chinese zihao: No. 5 is 10.5 pt, and Chinese “small 4” is 12 pt

Gōsū (“number sizes”) is the Japanese way of naming font sizes from the letterpress era. The larger the number, the smaller the type, and JIS Z 8305 assigns each size a point value. The default font size of 10.5 pt in Japanese Word comes from the size of No. 5 (gogō).

The gōsū mm values are calculated with the 0.3514 mm JIS point. Word and similar apps treat the same numbers as DTP points, so Word's 10.5 pt is about 3.70 mm, about 0.01 mm larger than metal-type No. 5 (about 3.69 mm). It is not a difference you need to worry about for everyday documents.

In the Chinese versions of Word and WPS, font sizes are chosen by zihao. The names look like the Japanese gōsū, but there are in-between sizes such as xiaosi (“small 4”) and xiaowu (“small 5”), and some point values differ from the Japanese sizes. If a Chinese official document or thesis format says “body text in xiaosi”, it means 12 pt.

The Japanese gōsū and Chinese zihao share the same point value only for the initial size (42 pt), No. 3 (16 pt), No. 4 (14 pt) and No. 5 (10.5 pt). Nos. 1, 2, 6, 7 and 8 have different values, so a document that says “No. 2” means a different size depending on which country it comes from (Japanese No. 2 is 21 pt; Chinese No. 2 is 22 pt).

Web px and print pt: 16 px is 12 pt, and 10 pt is about 49 pixels at 350 dpi

A CSS px is not a physical dot on the screen but a length defined as 1/96 inch. A point is 1/72 inch, so 1 pt = 96 ÷ 72 = 4/3 px and 1 px = 0.75 pt. The browser default text size of 16 px is the same as 12 pt (about 4.23 mm, about 16.9 Q).

That said, if you measure 16 px text on a phone or computer screen with a ruler, it will not necessarily be exactly 4.23 mm, because devices scale the display to suit the viewing distance. Think of the px–pt conversion as the correspondence between sizes “when printed” and “in the design data”.

In print images (flyers or comic and zine pages made in Photoshop or illustration apps), you need to think of text size in pixels. The pixel count is “mm ÷ 25.4 × dpi”. For example, 10 pt text (about 3.53 mm) in a 350 dpi image is 3.53 ÷ 25.4 × 350 = about 48.6 pixels.

If you add text after fixing the image resolution, it becomes harder to check the finished size. What dpi printing needs, and how to work out pixel counts, are explained in detail in the difference between image resolution and dpi.

Calculating leading, line gap and character pitch: at 13 Q with 21 H leading, the gap is 2 mm and line-height is about 1.615

The spacing between lines affects readability as much as the font size does. Two terms that are easy to mix up here are leading (line feed) and line gap. Leading is the distance from the top of one line's characters to the top of the next line's characters. The line gap is the empty space between the characters of the two lines.

In Japanese phototypesetting specifications, font size is written in Q and leading in H. Both are 0.25 mm, so you can subtract one from the other directly; that is the convenience of Q and H. The idea is the same when you set type in points: the “Leading” field in Illustrator and InDesign holds the leading, not the line gap.

For Japanese body text, leading is often 1.5 to 1.8 times the font size (a gap of half to 80% of the character size), and wider leading reads better the longer the lines are in horizontal text. The common CSS line-height of around 1.7 on the web follows the same idea. If the gap is too narrow, the eye has trouble moving to the next line; if it is too wide, paragraphs stop looking like units.

The spacing from one character to the next (character pitch) equals the font size in solid setting, with nothing tightened. Tracking in InDesign and Illustrator is in units of 1/1000 em, so setting 50 on 13 Q (3.25 mm) text widens the spacing by about 0.16 mm, and 100 by about 0.33 mm. To widen the pitch by 1 H (0.25 mm), use a tracking of about 77.

Calculating the type area: the formula from characters per line and lines

The type area (hanzura) is the rectangle on the page that holds the body text. When making a novel, a zine or a company newsletter in Japanese, it is common to decide characters per line and lines first, such as “13 Q, 38 characters × 16 lines”, and then work out the type area and margins from that. The type area can be calculated with the following formulas.

For example, vertical text at 13 Q, solid setting, 21 H leading, 38 characters × 16 lines has a line length (the height of the type area) of 37 × 3.25 + 3.25 = 123.5 mm and a length across lines (the width of the type area) of 15 × 5.25 + 3.25 = 82 mm, giving 608 characters per page. Centred on a bunko page (A6, 105 × 148 mm), the margins are 11.5 mm left and right and 12.25 mm top and bottom.

In vertical two-column setting, the columns are stacked top and bottom. One column is 19 × 3.25 + 3.25 = 65 mm tall, so two columns plus a 7.5 mm gap make 65 × 2 + 7.5 = 137.5 mm. In horizontal two-column setting, the columns sit side by side and the gap goes into the width.

Working out how many characters × lines fit from the paper and margins

Sometimes it is the other way round: the paper size and margins are fixed, and you want to know how many characters and lines fit. In that case, subtract the top, bottom, gutter (binding side) and fore-edge (outer side) margins from the paper, and count how many characters fit in what remains.

The last A4 example uses the same conditions as Japanese Word's default page setup (35 mm top, 30 mm bottom, 30 mm left and right, 10.5 pt), and the calculation also gives 40 characters × 36 lines. Raising the A6 example from 13 Q, 21 H to 14 Q, 22 H gives 34 characters × 15 lines (510 characters), about 14% fewer characters per page. Since making the type just 1 Q larger can change the page count, for a book with a fixed number of pages it is safest to decide the font size and leading first and then adjust the amount of text.

Once the page count is fixed, you can also calculate the cover's spine width from the paper thickness. See how to calculate a zine's spine width for details. How to make 400-character manuscript paper, where each character gets its own square, is covered in how to print Japanese manuscript paper.

Typical font sizes by use: body text, business cards, flyers and the web

There is no single correct font size, but knowing the commonly used ranges helps you judge whether a specification is large or small. The table below gives general guidelines for Japanese print; they vary with the typeface, the readers and the page size.

Materials for older readers and notices read from a distance often use 12 pt (about 17 Q) or more even for body text. Conversely, below 6 pt (about 8.5 Q) the thin horizontal strokes of Mincho (serif) typefaces tend to fade and become hard to read, so about 7 pt is a sensible minimum even for fine print.

Note that font size is not the height of the characters themselves but the size of the square frame they sit in (the virtual body). The actual shapes of kanji and kana (the face) are a bit smaller than that frame, and Latin capitals and digits are shorter still. This is why the same 13 Q can look larger or smaller depending on the typeface. The same thinking applies when a single character is several centimetres tall, as on fan boards or posters; see also letter size guidelines for fan boards.

Common mistakes with Q and points

• Thinking Q and H are different lengths: both are 0.25 mm. Q is simply used for character size and H for the length of advances
• Entering the line gap in the leading field: if you mean “8 H gap” and enter 8 H as the leading, the lines overlap. Leading = font size + line gap
• Swapping Q and pt with the same number: turning 13 Q into 13 pt makes the type about 1.41 times larger; turning 10 pt into 10 Q makes it about 0.71 times the size
• Putting a px value straight into a pt field: 16 px is 12 pt. When reusing numbers from a web design mockup for print, multiply by 0.75
• Mixing up Japanese and Chinese number sizes: some share a name but differ in size, such as No. 2 (Japan 21 pt, China 22 pt) and No. 6 (Japan 8 pt, China 7.5 pt)
• Judging size by how it looks on screen: screens are scaled, so always check print font sizes by printing at actual size

Even when you think you printed at actual size, a printer's “fit to page” setting may have shrunk it. When checking font sizes on paper, first make sure it printed at 100%. How to fix this is explained in why prints come out smaller and how to fix it.

FAQ

How many points is 13 Q?

13 Q is 13 × 0.25 = 3.25 mm, which is about 9.21 pt in DTP points (about 0.3528 mm). Multiplying Q by about 0.709 gives points. For mental math, “Q × 0.7” gives about 9.1 pt.

How many Q (kyu) is 10 pt?

10 pt is about 3.53 mm, or about 14.11 Q. Multiplying points by about 1.411 gives Q. 9 pt is about 12.7 Q, 12 pt is about 16.9 Q, and 10.5 pt (the Japanese Word default) is about 14.8 Q.

What is the difference between Q (kyu) and H (ha)?

Both are the same length, 0.25 mm. Q is used for character size and H for advances such as leading and character pitch. “13 Q, 21 H” means a 3.25 mm character size and 5.25 mm leading, with an 8 H (2 mm) line gap.

What is the difference between leading and line gap?

Leading is the distance from the top of one line's characters to the top of the next line's. The line gap is the space between the characters, found as line gap = leading − font size. CSS line-height is leading divided by font size: about 1.615 for 13 Q with 21 H leading.

How many mm is Word's 10.5 pt?

About 3.70 mm (about 14.8 Q). 10.5 pt corresponds to the gōsū size No. 5; calculated with the JIS point (0.3514 mm), metal-type No. 5 is about 3.69 mm. With Japanese Word's default page setup (A4, 35 mm top, 30 mm bottom, 30 mm left and right), you get 40 characters × 36 lines.

How many points is 16 px?

12 pt. A CSS px is 1/96 inch and a point is 1/72 inch, so multiplying px by 0.75 gives pt. 16 px is about 4.23 mm, or about 16.9 Q.

What Q size is bunko paperback body text?

Usually around 12–13 Q (about 8.5–9.2 pt), with leading around 20–22 H. For vertical text at 13 Q, 21 H, 38 characters × 16 lines, the type area is 82 × 123.5 mm; centred on a bunko page (105 × 148 mm), that leaves margins of 11.5 mm left and right and 12.25 mm top and bottom.