Common Screen Resolutions

Optimize for

• Notebook: 1280x800 (many consumer notebooks)
• Netbook: 1024x600
• Desktop: 1440x900 / 1680x1050 (19"- und 22"-Widescreen-TFTs)
• iPad: 768x1024

Notebooks

• 1280x800 (13.3"-15.4", 16:10)
• 1440x900 (15.4", 16:10)
• 1680x1050 (15.4"+, 16:10)
• older notebooks cf. Desktops (1024, 1280, ...)

Desktops

• 1440x900 (19", 16:10)
• 1680x1050 (22", 16:10)
• 1920x1080 (23", 16:9)
• 1920x1200 (24", 16:10)
• 1024x768 (17", 4:3)
• 1280x1024 (19", 5:4)
• 1600x1200 (21", 4:3)

Netbooks

• 720x480 (7")
• 1024x600 (8.9")

Also use liquid layouts if you're awesome.