The ultrabook category was once a synonym for compromised performance in a thin chassis. That changed with the ARM processor revolution. Apple's M-series chips demonstrated that thin and powerful are not mutually exclusive, and Intel and Qualcomm followed with their own responses.
An ultrabook is defined by its constraints: typically under 1.3kg (2.9 lbs) and under 15mm thick, with integrated graphics and a focus on battery life over sustained heavy compute. Within those constraints, the best 2025 ultrabooks are genuinely excellent machines.
For macOS users, the MacBook Air M3 remains the benchmark. It weighs 1.24kg, has no fans, runs silently under any workload short of video rendering, and delivers 15+ hours of real-world battery life. The M3's single-chip design means performance is consistent — there's no throttling because there's no heat buildup.
For Windows users, the Lenovo ThinkPad X1 Carbon Gen 12 and the ASUS Zenbook S 13 OLED are the strongest options. The ThinkPad prioritizes keyboard and durability; the Zenbook prioritizes display quality and design.
What to look for: check the display resolution (1920×1200 minimum — avoid Full HD on anything above 13 inches as the pixel density becomes noticeable), confirm USB-C charging on both sides (not just one), and verify that the claimed battery life was tested at realistic screen brightness (200+ nits, not the manufacturer's 40-nit optimization setting).