Why this product
The Herman Miller Aeron Size A is the version of the Aeron sized for adults under 5’9” and 170 pounds. Most office chairs come in a single “average male” frame and are then padded or contoured to fit smaller users imperfectly. Herman Miller is one of the very few mainstream office furniture brands that physically tools three different frame sizes for the same chair, the Aeron Size A, B, and C are not the same chair with different upholstery, the frames are different.
That matters more than it sounds. A chair sized for a 5’10” average male body has a seat pan roughly 16.75 inches deep and a backrest about 22 inches tall. For a 5’4” user, that seat pan ends at the calf rather than the back of the knee, leaving the front edge digging into the thighs and the back unsupported by the lumbar curve. Padding does not fix geometry.
For this review I reference the Herman Miller spec sheet, the official sizing chart, and aggregate owner reports across Amazon and the Herman Miller direct listing. The Size A I sat in at the DWR Soho showroom was a graphite frame with fully adjustable arms.
What Herman Miller claims
Herman Miller positions the Size A as the Aeron for “the smaller 10 percent” of adult bodies. The published fit window is 4’10” to 5’9” and up to 170 pounds, with overlap into Size B territory between 5’4” and 5’9”. The seat width is 25.75 inches and the seat pan depth is dimensioned shorter than the Size B by roughly 1.5 inches.
The mechanical specifications are otherwise identical to the Size B. Same 8Z Pellicle mesh, same PostureFit SL lumbar system, same Kinemat tilt, same fully adjustable arm options, same 5-star aluminum base. The gas cylinder is shorter, which is what gives the Size A its lower seat height range of 14.75 to 19 inches versus the Size B’s 16 to 20.5 inches.
Certifications are identical to the Size B, BIFMA X5.1 for durability, GREENGUARD Gold for low emissions, and Cradle to Cradle Silver for recyclability. The 12-year parts-and-labor warranty applies the same way, including in-home authorized service.
Who should buy the Aeron Size A
Buy the Size A if:
- You are 5’9” or shorter, particularly if you are also under 170 pounds.
- You have spent years in chairs where the seat pan dug into the back of your calves or where you could not get the seat low enough for your feet to sit flat on the floor.
- You want the Aeron warranty and breathability without the wider frame.
- You sit eight or more hours a day at a desk.
Skip it if:
- You are over 5’9” or over 170 pounds, the frame will feel narrow and the seat pan will end short. Default to the Aeron Size B or Aeron Size C instead.
- Your budget is under $700, the Branch Ergonomic Chair is a better value at that tier and Branch publishes seat dimensions clearly.
- You need a headrest, no Aeron has one and adding one voids the warranty.
Frame fit: the part most reviews skip
Office chair reviews tend to focus on lumbar support and adjustability, but for petite users the dominant variable is frame geometry. Two measurements matter most: seat pan depth (front-to-back distance from the seat back to the front edge of the seat) and minimum seat height (lowest gas cylinder setting).
Seat pan depth on the Size A is shorter than the Size B. For a 5’4” user that means the back of the knee clears the front edge of the seat by roughly two finger widths when seated against the lumbar, the textbook ergonomic fit. On a Size B at the same posture the front edge digs into the calf, which over time forces the user to slide forward and lose contact with the lumbar pad.
Minimum seat height on the Size A is 14.75 inches versus 16 inches on the Size B. That 1.25-inch difference is what allows a 5’2” user to sit with both feet flat on the floor and thighs roughly parallel to the ground. Sit any higher and the thighs angle down, the pelvis tips forward, and the lumbar curve collapses regardless of how good the lumbar pad is.
8Z Pellicle mesh and PostureFit SL: identical to Size B
The mesh and lumbar system are mechanically identical to the Aeron Size B, just stretched across a smaller frame. The 8Z Pellicle is the suspension fabric Herman Miller has stretched across both the seat and back frame, divided into eight tension zones for differential support. The PostureFit SL is the dual pad lumbar system, one pad supports the sacrum (base of the spine, often ignored in chair design) and one supports the lumbar curve.
Both adjust independently using thumbwheels under the back frame. For petite users the smaller frame puts the lumbar pad in the right place by default, on a Size B the lumbar pad sits too high for many 5’4” users and cannot be adjusted low enough.
Warranty and resale
The 12-year Herman Miller warranty is identical across all three Aeron sizes, parts and labor, in-home authorized service, no exclusions for normal wear. Casters, gas cylinders, arm pads, and the Pellicle mesh are all covered. This is the longest warranty in mainstream office furniture and is the single biggest argument for the Aeron over cheaper alternatives.
Resale value of the Size A is lower than the Size B because the buyer pool is smaller, used Size A frames typically clear 30 to 40 percent of MSRP after 5 years versus 45 to 55 percent for the Size B. If you expect to resell within 3 years, factor that in. If you are buying for a decade of use, it does not matter.
For more on how we evaluate office chairs against BIFMA standards and frame sizing, see our methodology page.
Herman Miller Aeron Size A Graphite vs. the competition
| Product | Our rating | Mesh | Warranty | Min seat height | Price | Verdict |
|---|---|---|---|---|---|---|
| Herman Miller Aeron Size A | ★★★★★ 4.6 | 8Z Pellicle | 12 yr | 14.75 in | $1395 | Top Pick Smaller Frames |
| Herman Miller Aeron Size B | ★★★★★ 4.7 | 8Z Pellicle | 12 yr | 16 in | $1495 | Editor's Choice Premium |
| Steelcase Leap V2 | ★★★★★ 4.6 | Fabric | 12 yr | 15.5 in | $1349 | Top Pick Adjustability |
| Branch Ergonomic Chair | ★★★★☆ 4.3 | Polyester | 7 yr | 16.5 in | $599 | Top Pick Mid-Range |
Full specifications
| Frame size | Size A (small, fits adults under 5'9'' and 170 lb) |
| Seat material | 8Z Pellicle elastomeric mesh |
| Lumbar system | PostureFit SL, dual pad sacral + lumbar |
| Tilt mechanism | Kinemat tilt with optional forward tilt |
| Arm style | Fully adjustable arms (height, width, pivot, depth) |
| Weight capacity | 300 lb (BIFMA X5.1 verified) |
| Seat height range | 14.75 to 19 inches |
| Seat width | 25.75 inches |
| Base | 5-star aluminum, graphite |
| Certifications | BIFMA X5.1, GREENGUARD Gold |
| Warranty | 12 year, parts and labor |
| Country of origin | Assembled in Michigan, USA |
Should you buy the Herman Miller Aeron Size A Graphite?
If you are 5'9'' or shorter and have spent years in office chairs that swallow you, the Aeron Size A is the version that actually fits. The frame is roughly an inch and a half narrower at the shoulders, the seat pan is shorter, and the gas cylinder lowers further. You get the same 8Z Pellicle mesh, PostureFit SL lumbar, and 12-year warranty as the Size B for $100 less. The small adult market is genuinely underserved, and Herman Miller is one of the few makers who builds three real frame sizes.
Frequently asked questions
Is the Aeron Size A worth the premium over the Size B?+
It is not a premium, the Size A is actually $100 less than the Size B at $1,395 vs $1,495. The savings comes from the smaller frame using less material. If you are 5'9'' or under, Size A is both the better fit and the better value.
How do I know if I need Size A or Size B?+
Herman Miller's official sizing chart puts adults under 5'9'' and under 170 lb in Size A territory. Adults 5'4'' to 6'2'' and under 350 lb fit Size B. There is overlap from 5'4'' to 5'9'', within that range Size A is more enveloping while Size B leaves more clearance under the thighs.
Aeron Size A vs Steelcase Leap for petite users: which is better?+
The Aeron Size A wins on raw fit, the Leap V2 only comes in one frame size and the seat pan is dimensioned for an average male body. Petite users routinely report the Leap's seat being too deep, with knees not bending past the front edge. The Aeron Size A's seat pan is roughly an inch shorter and the cylinder is shorter.
Can I add a headrest to the Aeron Size A?+
Herman Miller does not offer a factory headrest for any Aeron size. Third-party headrests exist but installing them voids the 12-year warranty. If you need a headrest, look at the [Steelcase Leap](/reviews/steelcase-leap-onyx) or the [Secretlab TITAN Evo 2022](/reviews/secretlab-titan-evo-2022).
What is the resale value of an Aeron Size A?+
Lower than the Size B. The buyer pool for Size A is smaller because most adults fit Size B, so used Size A chairs typically sell for 30 to 40 percent of MSRP after 5 years versus 45 to 55 percent for the Size B. If resale matters more than fit, default to Size B.
📅 Update log
- May 9, 2026Initial review published with sizing comparison against Size B and Steelcase Leap V2.
Morgan Davis
Morgan Davis writes for The Tested Hub.
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