Asus Zenfone 9 review: specs, battery & used prices

Summary

The Asus Zenfone 9 is the 2022 compact flagship that shrank flagship silicon into a 5.9-inch, 169 g body: a Snapdragon 8 Plus Gen 1, a stabilised 50 MP main camera, and IP68 sealing. Launched at $800, 6/128 GB units now sell for around $259 with a five-sale sample — one of the cheapest routes into a genuinely small high-end phone.

Display and design

The 5.9-inch OLED runs at 120 Hz with an 800-nit peak — screen quality 61/100 on our axis. Compactness scores 98/100, among the very best we track: this is a one-handed phone without a midrange chip inside. IP68 protection is standard, unusual for a small device.

Performance

The Snapdragon 8 Plus Gen 1 was the efficient correction to 2022's hot flagships, and our gaming score of 32/100 keeps modern titles playable with settings trimmed. Everyday responsiveness scores 90/100 — the small body never translated into a small-feeling UI.

Camera

The camera story is the 50 MP main sensor with Asus's gimbal-style stabilisation, producing unusually steady handheld video and confident low-light stills for the size; the 12 MP ultrawide completes the pair, and there is no telephoto. Video records to 8K at 24 fps. Our camera score of 33/100 reflects the two-lens simplicity, not weak main-sensor output.

Battery and charging

The 4,300 mAh battery earns a 26/100 battery-life score — a full day for moderate use, no more — and 30 W charging scores 12/100, among the slower routines in the catalog. The small chassis sets these limits; overnight charging is the rhythm.

Verdict

At around $259 used, the Zenfone 9 is the compact specialist's pick: flagship platform, IP68, and a stabilised main camera in a body nothing else in the class matches, with resale confidence at 100/100. Battery and charging speed are the price of the size. The Zenfone 10 refined the formula a year later; the Xperia 5 II is the other established small-flagship route in our catalog.