Size

from	to	note
1 cm	0.3937 in
1 in	2.54 cm
1 cm	28.346 pt	72dpi
1 cm	37.795 px	96dpi
1 in	72.000 pt	72dpi
1 in	96.000 px	96dpi
1 rem	16 px	default

• A4 为 A3 对折大小 - 可以此类推
• DPI - Dots Per Inch - 打印
  • 600 - 归档
  • 300 - 打印
  • 150
  • 72 - 普通
• PPI - Pixels Per Inch - 显示器

  • = 200 - 视网膜屏, HiDPI

• dppx - Device Pixel Per X
  • 1=96dpi
  • 2=192dpi
  • 会跟随缩放变化
  • CSS resolution
  • window.devicePixelRatio
• DPCM - dots per cm
• 银行卡/身份证
  • 8.56 cm × 5.398 cm
  • 85.6 mm × 53.98 mm
  • 3.37 inch × 2.125 inch × 0.0625
  • px - 1011 × 638
  • ISO/IEC 7810 - ID-1

Social	Size	Ratio
FB Page Cover	1640×664 px	1:2.46
FB Shared Image	1200×630 px	1:1.91
FB Event Image	1920×1080 px	16:9
FB Group Header	1640×856 px	1:1.91
Instagram	1080×1080 px	1:1
Insta Story	1080×1920 px	9:16
Youtube Profile	800×800 px	1:1
Youtube Cover	2560×1440 px	16:9
Twitter Profile	400×400 px	1:1
Twitter Header	1500×500 px	3:1

Print	Size	Pixel	pt
A3	297×420 mm
A4	210×297 mm	2480×3508	595.28, 841.89
A5	148×210 mm
B3	353×500 mm
B4	250×353 mm
B5	176×250 mm		498.9, 708.66
JIS B5	182x257 mm
Letter	8.5×11 in
Ledger	11×17 in
Business Card	3.5×2 in

• 1mm=2.83465pt
• 凭证封面
  • 252x148
  • 增票 243mm×142mm
  • A5 212x150
  • 240mm×140mm
  • 245mm×130mm
  • 245mm×150mm
  • 245mm×145mm
• Japanese Industrial Standards (JIS)
• https://github.com/diegomura/react-pdf/blob/master/packages/layout/src/page/getSize.js
• https://papersizes.io/japanese/jb5

Photo	inch	mm	note
Wallet	2×3 in
Enprint	3.5×5 in
-	8×12 in
-	12×18 in
-	16×24 in
-	20×30 in
-	24×36 in
2R	2.5×3.5 in
3R,L,5 寸	3.5×5 in
4R,KG,6 寸	4×6 in	102×152 mm
5R	5×7 in
6R	6×8 in
S8R,A4	8×10 in
10R	10×12 in
1 寸		25 x 35 mm
2 寸证件照		37  x  49 mm
标准 2 寸		37 x 53 mm

• 4R - 标准 135 底片尺寸
• R -> Rect
  • 2,4,6,8,10,12
• S -> Sequre
  • 4,6,8,10
• Cube - 2x3
• Wallet - 3x4
• 日本标准
  • E,L,KG,2L,8P,6P,6PW,4P,4PW
• Photo print sizes

Screen	Size
VGA	640×480 px
XGA	1024×768 px
HD	1280×720 px
-	1366×768 px
-	1440x900
-	1536×864 px
-	1600×900 px
Full HD	1920×1080 px
2K	2048×1080 px
UHD	3840×2160 px
4K	4096×2160 px

• https://gs.statcounter.com/screen-resolution-stats/desktop/worldwide

Mobile	Size
iPhone 4	640×900 px
iPhone 5	640×1136 px
iPhone 6 7 8	750×1334 px
iPhone 6+ 7+ 8+	1080×1920 px
iPhone X	1125×2436

AD	Size
Banner	468×60 px

Size	Screen
2880 x 1800	MBP 15
2560 x 1440	QHD/WQHD

system_profiler SPDisplaysDataType | grep Resolution

• https://screensizemap.com/

CSS Absolute length units

Unit	Name	Equivalent to	cn
cm	Centimeters	1cm = 96px/2.54	厘米
in	Inches	1in = 2.54cm = 96px	英寸
mm	Millimeters	1mm = 1/10th of 1cm	毫米
pc	Picas	1pc = 1/6th of 1in	派卡
pt	Points	1pt = 1/72th of 1in	点
px	Pixels	1px = 1/96th of 1in	像素
Q	Quarter-millimeters	1Q = 1/40th of 1cm	四分之一毫米

• https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Values_and_Units
  • Absolute length units

Resolution

Resolution	Ratio	Quality	low motion	high motion	audio
426x240	16:9	240p	400k	600k	64k
640x360	16:9	360p	700k	900k	96k
640x480	4:3	SD 480p	1000k	1200k	128k
854x480	16:9	480p	1250k	1600k	128k
1280x720	16:9	HD 720p	2500k	3200k	128k
1280x720	16:9	HD 720p 60fps	3500k	4400k	128k
1920x1080	16:9	FHD 1080p	4500k	5300k	192k
1920x1080	16:9	FHD 1080p 60fps	5800k	7400k	192k
3840x2160	16:9	4k	14000k	18200	192k
3840x2160	16:9	4k 60fps	23000k	29500k	192k

Res. Type	Name	Ratio	Size
SD	480p	4:3	640x480
HD	720p	16:9	1280x720
FHD	1080p	16:9	1920x1080
QHD	1440p	16:9	2560x1440
2K	1440p	16:9	2560x1440
4K UHD	2160p	16:9	3840x2160
8K FUHD	4320p	16:9	7680x4320

• 16:9 = 1.77
• SD - Standard Definition
• HD - High Definition
• FHD - Full High Definition
• UHD - Ultra High Definition
• QHD - Quad High Definition
• List of common display resolutions

abbr.	size	notes
ntsc	720x480
pal	720x576
qntsc	352x240
qpal	352x288
sntsc	640x480
spal	768x576
film	352x240
ntsc-film	352x240
sqcif	128x96
qcif	176x144
cif	352x288
4cif	704x576
16cif	1408x1152
qqvga	160x120	1/4 QVGA
qvga	320x240	1/4 VGA
vga	640x480
svga	800x600
xga	1024x768
uxga	1600x1200
qxga	2048x1536
sxga	1280x1024
qsxga	2560x2048
hsxga	5120x4096
wvga	852x480
wxga	1366x768
wsxga	1600x1024
wuxga	1920x1200
woxga	2560x1600
wqsxga	3200x2048
wquxga	3840x2400
whsxga	6400x4096
whuxga	7680x4800
cga	320x200
ega	640x350
hd480	852x480
hd720	1280x720
hd1080	1920x1080
2k	2048x1080
2kflat	1998x1080
2kscope	2048x858
4k	4096x2160
4kflat	3996x2160
4kscope	4096x1716
nhd	640x360
hqvga	240x160
wqvga	400x240
fwqvga	432x240
hvga	480x320	1/2 VGA
qhd	960x540
2kdci	2048x1080
4kdci	4096x2160
uhd2160	3840x2160
uhd4320	7680x4320

• VAG - Video Graphics Array
  • 640x480
• QVGA - Quarter VGA
  • 1/4 VGA

Avatar

• github avatar 460x460
• Instagram
  • avatar 320x320
  • Square 1080x1080
  • Portrait 1080x1350
  • Landscape 1080x566
  • Stories & Reels 1080x1920

Def

// mm
const Size = {
  A1: { width: 594, height: 841 },
  A2: { width: 420, height: 594 },
  A3: { width: 297, height: 420 },
  A4: { width: 210, height: 297 },
  A5: { width: 148, height: 210 },
  A6: { width: 105, height: 148 },
};