Herman Miller Cosm Low Back vs X-Chair X3

Side by side from official specifications, sourced prices and User Insights. No written comparison exists for this pair yet.

Herman Miller

Herman Miller Cosm Low Back

$1,345 – $1,820

X-Chair

X-Chair X3

$979

20.5 lb

lighter: Herman Miller Cosm Low Back weighs less than X-Chair X3 (official specs)

Differences at a glance

Herman Miller Cosm Low BackX-Chair X3

Price: $1,345 – $1,820$979
Seat height: 14.8–21.4 in (37.6–54.4 cm)17.69–22 in
Seat depth: 15.9 in (40.4 cm)16.75–19.25 in
Load capacity: 350 lb (158.8 kg)275 lb (125 kg)
Arms: Leaf Arms; Height-Adjustable Arms; Fixed Arms; No Arms; Arm Height: 7.3–11.7"4-Dimensional armrests come standard (up, down, side-to-side, front-to-back); option to upgrade to FS 360 rotational armrests; Armrest Height 5.875in - 8.875in
Warranty: 12-year, 3-shift warranty, with limited exceptions5 years (all parts and materials); 15 years (non-moving metal components, chair frame)

Which is cheaper, the Herman Miller Cosm Low Back or the X-Chair X3?

The X-Chair X3 is cheaper to start: $979 versus $1,345 for the Herman Miller Cosm Low Back at the brand stores (Oct 2026).

Which has a higher weight capacity?

The Herman Miller Cosm Low Back, rated for 350 lb versus 275 lb for the X-Chair X3.

What do owners mention most?

Recline and tilt for the Herman Miller Cosm Low Back, and comfort for the X-Chair X3, based on review summaries.