SIHOO M18 vs M57: Which Should You Choose? (October 2026)

On this page (8 sections)

1. SIHOO M18 vs M57: what are the main differences?
2. Which chair fits your height and desk?
3. How do the M18 and M57 compare on lumbar support?
4. Which chair gives you more room to move?
5. Are the M18's 2D or M57's 3D armrests a better fit?
6. Is the M57 seat material different from the M18?
7. Which chair is easier to assemble and maintain?
8. Should you choose the SIHOO M18 or M57?

Choose the SIHOO M18 for a simpler set of adjustments, or the M57 for 3D armrests and a defined recline range. Both chairs have mesh backs, headrests and adjustable lumbar support, but the M57 gives you more ways to fine-tune your position.

The M18's recommended height range is 5 ft 6 in to 6 ft 2 in. The M57's details don't provide a matching range, so check your fit carefully before choosing.

SIHOO M18 vs M57: what are the main differences?

The M57 has more specified adjustment options, while the M18 gives a recommended user height range. Both are mesh-back chairs with lumbar support and headrests.

The M18 has seat height, headrest, lumbar and back support adjustments, plus 2D armrests. It includes tilt and adjustable recline features, but no recline angle range is specified.

The M57 has 3D armrests, a headrest that tilts and lifts, and lumbar support that adjusts in height and depth. Its recline range is stated as 90° to 126°.

Both seat materials deserve a closer look. The M18 has sponge listed as its fill material, while the M57 is described with a waterfall-edge seat but its seat fill isn't specified here.

Which chair fits your height and desk?

The M18 has a clearer fit reference if you're between 5 ft 6 in and 6 ft 2 in. For either chair, compare its dimensions with your desk, room and preferred sitting position.

The M18 is recommended for that height range. This is a starting point, not a guarantee that the chair will feel right for your legs, torso or desk height.

The M57's seat measures 25.59 inches wide and 30.31 inches deep in its listed dimensions. The M18's overall dimensions are given as 27.5 x 21 x 11 inches, but that entry doesn't label the order of those measurements consistently.

Measure your desk and the space where the chair will move. For a deeper fit checklist, see how to choose an ergonomic office chair.

SIHOO M18 vs M57 for shorter and taller users

Use the M18's stated height range as a useful first screen, then confirm seat and desk fit. The M57 doesn't have a stated recommended height range in the details available here.

If you fall outside the M18 range, that alone doesn't tell you the M57 will fit better. Check the seat height range and other fit details with the seller before ordering, since those measurements aren't included here.

Consider where your feet rest and whether the seat supports your thighs without pressing behind your knees. A chair that can be adjusted is only useful when its adjustment range suits your body and desk.

How do the M18 and M57 compare on lumbar support?

Both chairs offer adjustable lumbar support; the M57 specifies adjustment in height and depth. Pick the M57 if changing both positions matters to you.

The M18 includes adjustable lumbar support and back support adjustment. Its details don't say whether the lumbar support moves in depth.

The M57's lumbar support shifts in height and depth to fit the curve of the lower back. That gives you more stated control, though more adjustment doesn't guarantee a better fit for every person.

Set the lumbar support so it meets your lower back without pushing you forward. If you use a separate cushion, our guide to choosing a lumbar pillow for an office chair explains what to consider.

Which chair gives you more room to move?

The M57 gives you a specific recline range, from 90° to 126°. The M18 lists tilt and adjustable recline, but doesn't state an angle range.

That makes the M57 easier to compare if you want to lean back during breaks. The chair also swivels, and its headrest tilts and lifts.

The M18 also has tilt and adjustable recline features, so it isn't limited to a fixed upright posture. The available details don't say how far it reclines or how its tilt locks work.

If you rarely recline, those differences may matter less than height fit and armrest position. If you shift posture often, the M57's stated range gives you a clearer starting point.

Are the M18's 2D or M57's 3D armrests a better fit?

The M57 has more armrest adjustment directions, with 3D armrests versus the M18's 2D armrests. Choose based on how closely you need to align the armrests with your arms and desk.

The M18's 2D armrests cover basic positioning, while the M57 adds another adjustment direction. The available information doesn't define the exact movement dimensions for either chair.

Check whether the armrests can tuck under your desk and whether they let your shoulders stay relaxed. If your desk is too high, armrest movement alone won't fix the setup.

The M18 may be enough if you mainly need arm support at a consistent desk height. The M57 offers more options if you regularly change arm position.

Is the M57 seat material different from the M18?

The M18 specifies sponge fill, while the M57's seat fill isn't specified here. The M57 does describe a waterfall-edge seat designed to support the thighs and improve circulation.

Both chairs have mesh backs, so they share a breathable back material. The M57's back is described as split, and the M18 has flexible mesh.

Don't assume that the M57's waterfall edge means its cushion feels softer or firmer. If seat feel is your priority, check the exact model in person or confirm the material and return terms before ordering.

Which chair is easier to assemble and maintain?

The M18 has a stated 8-step assembly process, while the M57 requires assembly. Both chairs include a 3-year warranty, based on their stated support terms.

SIHOO describes the M18 as simple to assemble with instructions in 8 steps. The M57's details say assembly is required but don't give a step count.

The M18's stated support terms include free returns and refunds within 30 days for faults or quality issues, plus replacement parts during the 3-year warranty period. The M57's terms describe a 3-year warranty, 30-day returns and free replacement parts if needed.

Confirm the terms that apply in your region before buying. To compare more options from the brand, browse our guide to the best SIHOO ergonomic office chairs.

Should you choose the SIHOO M18 or M57?

Choose the M18 if its stated height range suits you and 2D armrests cover your needs; choose the M57 if you want 3D armrests and a specified recline range. Both offer mesh backs, adjustable lumbar support and headrests.

The M18 is the more direct match when you want a clear height recommendation and a straightforward set of adjustments. Read our SIHOO M18 review for a closer look at that model.

The M57 is worth considering if you want lumbar depth adjustment and more armrest positioning. If neither seems like the right fit, compare the SIHOO Doro C300 Pro review and SIHOO Doro C300 review for other options.

For a simple decision rule, pick the M18 when your height falls within its recommended range and its adjustment set is enough. Pick the M57 when its extra armrest movement and stated recline range better match how you work.

Frequently asked questions

Is the SIHOO M18 or M57 better?

The M18 is a fit for people who want adjustable lumbar support, a headrest and 2D armrests with a stated recommended height range of 5 ft 6 in to 6 ft 2 in. The M57 adds 3D armrests, lumbar depth adjustment and a stated 90° to 126° recline range.

Does the SIHOO M57 have a different seat material from the M18?

The M57's seat has a waterfall edge and is described as supporting the thighs, while the M18 has a sponge fill listed for its seat. The available M57 details don't name its seat fill, so compare the chair in person if seat material is a deciding factor.

Which chair has more adjustable armrests?

The M57 has 3D armrests, while the M18 has 2D armrests. If you need more ways to position your arms, the M57 has the broader adjustment description; check that its movement range works with your desk and preferred sitting position.

Are both SIHOO chairs suitable for long workdays?

Both chairs include adjustable lumbar support and headrests, and both have mesh backs. The M57 specifies a recline range from 90° to 126°, while the M18 includes tilt and adjustable recline features without a stated angle range.

Comfort still depends on your fit and setup.