The catch
SIHOO M18 Ergonomic Office Chair
You cannot change the seat depth, and the armrests move only up and down.
Side by side
SIHOO M18 vs M57: M57 differs in arm control and seat material, not in basic seat size
Quick verdict
If you want a foam cushion and a lighter chair, M18 fits. M57 brings a mesh seat and more arm positioning, with similar fixed seat dimensions.
Before you buy
Why, and what it costs you
Arm movement changes fit more than seat depth does
The seats are only a fifth of an inch apart, but M57 has extra directions for arm position.
Where this comes from
18.11 minus 17.91 leaves 0.20 inch. M18's arms adjust up and down, and M57 also lists lateral and fore-aft movement.
The catch
SIHOO M57
The mesh is firm. Shorter legs may find the fixed seat depth too long.
SIHOO M18 Ergonomic Office Chair
- Why pick it
- Padding under your thighs is your preference.
- Moving the chair between rooms is easier when it is lighter.
- The catch
- You cannot change the seat depth, and the armrests move only up and down.
SIHOO M57
- Why pick it
- Seat airflow outweighs a foam cushion for you.
- The arm pads need to shift forward, backward or sideways for you.
- The catch
- The mesh is firm. Shorter legs may find the fixed seat depth too long.
We may earn a commission from qualifying Amazon purchases. How we make money
What this page compares
Padded versus mesh seating, arm adjustment, handling weight and fixed seat depth are compared for SIHOO M18 and M57, ahead of choosing a budget task chair.
Which one fits
Pick the situations that sound like you
Like a foam cushion better
The seat on M18 is padded.
- SIHOO M18 Ergonomic Office Chair
- Better fit
- SIHOO M57
- Caution
Need air to flow beneath the seat
On M57 both the seat and the back are mesh.
- SIHOO M18 Ergonomic Office Chair
- Good
- SIHOO M57
- Better fit
Need arm pads that move
With M57 you get 3D arm positioning.
- SIHOO M18 Ergonomic Office Chair
- Caution
- SIHOO M57
- Better fit
Need seat depth that adjusts
Neither depth can change.
- SIHOO M18 Ergonomic Office Chair
- Caution
- SIHOO M57
- Caution
In practice
Differences you will notice
Arm movement changes fit more than seat depth does
The seats are only a fifth of an inch apart, but M57 has extra directions for arm position.
How we worked this out
18.11 minus 17.91 leaves 0.20 inch. M18's arms adjust up and down, and M57 also lists lateral and fore-aft movement.
M18 sheds about seventeen percent of the chair weight
It weighs 7.7 pounds less.
How we worked this out
44.8 minus 37.1 leaves 7.7. Divide that by 44.8 and you get 17.2 percent.
Neither answers a need for depth that adjusts
Similar 20.08-inch listed hip widths and 330-pound ratings leave the fixed seat geometry unchanged.
How we worked this out
Each manufacturer page lists a 20.08-inch maximum hip width and 330 pounds. No seat-depth slider is listed on either.
Option A
SIHOO, M18, Black
M18 Ergonomic Office Chair
Manual controls for lumbar height and depth, an adjustable headrest and a mesh back come with the cushioned seat of this task chair.
- Best for
- An entry-level price for a padded seat and adjustable head support
Facts we checked
- Maximum hip width is 20.08-inch and seat depth is 17.91-inch, as listed by the manufacturer.
- Recline goes as far as 126 degrees.
- Lumbar position can be moved vertically and horizontally, and the headrest both moves vertically and pivots.
- A three-year warranty and a 330-pound maximum load are listed by the manufacturer.
Option B
SIHOO, Black
M57
This budget all-mesh chair has been around a long time. It offers adjustable lumbar, 3D arms, a headrest and a deeper recline.
- Best for
- Medium to taller users who want airflow and head support on a budget
Facts we checked
- Arms with three-dimensional adjustment move up and down, front to back, and pivot
- Lumbar support can be shifted both vertically and horizontally
- A 330 lb maximum load and a 126 degree recline are listed in the official specifications
Spec by spec
Where they really differ
| Spec | SIHOO M18 Ergonomic Office Chair | SIHOO M57 | In practice |
|---|---|---|---|
| Seat material | Foam cushion | Mesh | Seating surface and ventilation both differ. |
| Arm adjustment | Height only | 3D positioning | M57 has more ways to move the pads toward the task. |
| Fixed seat depth | 17.91 inches | 18.11 inches | A small difference in depth is no replacement for a seat slide. |
| Chair weight | 37.1 pounds | 44.8 pounds | M18 weighs less to move. |
| Overall depth | 27 inches | 28 inches | Bare depth needed on M18 is slightly less. |
Trade-offs
What each pick costs you
With SIHOO M18 Ergonomic Office Chair
- You need to assemble it.
With SIHOO M57
- Premium commercial chairs do better on build refinement, caster quality and warranty depth.
Change of plan
When the answer changes
You need an adjustable seat that gets shorter, not a different surface
Neither model fits. Breck's depth adjusts from 15 to 17.25 inches, and it comes with a 325-pound rating and a lower seat-height range.
Decision guide
How to decide
A foam cushion and a lighter chair point to M18. M57 adds a mesh seat and more arm positioning, and its fixed seat dimensions are similar.
In a warm room
The mesh seat on M57 exposes more of the seating surface to airflow. M18 still has a mesh back, so it is not an all-upholstered chair. Go with the surface you already tolerate well, since mesh tension and cushion firmness can feel very different under the thighs.
With a compact keyboard setup
On M57 the arm pads can move toward the desk task and not just rise or lower. That matters if fixed lateral spacing leaves your elbows unsupported. Make sure the arm frame itself clears the desk before you count pad travel as a complete solution.
For shorter sitters
Almost no difference separates the two fixed depths. If either presses behind your knees, switching between them may not fix the problem. Your next comparison should be a chair with a shorter adjustable seat range.
What this page can’t tell you
- We compared published controls and dimensions. Comfort and durability were not tested hands-on.
- Neither chair is offered as a pain treatment, and optional features are not assumed to be included.
By the numbers
What the data shows
What we found across the office chairs we compare, plus the checked facts behind each finding.
How many fit
None of the 32 models checked meets all of “I want solid basics without paying premium prices”, “I like a suspended mesh seat”, “I like a padded seat”, and “I need flexible arm support for my keyboard and devices”, so the pick goes to the closest practical compromise.
0 models fit, out of 32 checkedShow the facts and the math
How we countedThe count uses each product's current fit ratings for “I want solid basics without paying premium prices”, “I like a suspended mesh seat”, “I like a padded seat”, and “I need flexible arm support for my keyboard and devices”. A need with no documented match is not counted.
| Product | Needs it meets | Facts we checked | Sources |
|---|---|---|---|
| SIHOO M18 Ergonomic Office Chair |
|
|
|
| SIHOO M57 |
|
|
Ready to buy
See today’s price and what owners say
Open either model on Amazon for the current price, customer reviews and delivery options.
SIHOO M18 Ergonomic Office Chair
Padding under your thighs is your preference.
See price & reviews on AmazonSIHOO M57
Seat airflow outweighs a foam cushion for you.
See price & reviews on AmazonEach link opens in a new tab.
We may earn a commission from qualifying Amazon purchases. How we make money