SIHOO M18 Ergonomic Office Chair Review: Worth It? (October 2026)
The SIHOO M18 suits desk users who want adjustable head and lower-back support, with a mesh back for airflow. Choose it if its stated height range matches you and its seat and arm positions work with your desk.
On this page (9 sections)
- What does the SIHOO M18 offer?
- What should you measure before buying the M18?
- How do you set up the M18 for desk work?
- Is the M18's capacity enough for your needs?
- How does the SIHOO M18 compare with alternatives?
- What should you check during assembly and the first few days?
- How should you care for the chair and use it through the day?
- Should you choose the SIHOO M18?
- Sources
The SIHOO M18 is a sensible choice for desk users who want adjustable head and lower-back support, provided the seat fits their legs and the arms work with their desk. Its mesh back also makes it worth considering for a warm home office.
The key buying question is fit: can you sit back, keep your feet supported and reach your keyboard without stretching? Use those checks to decide between the M18, TRALT and FelixKing.
What does the SIHOO M18 offer?
The M18 gives you several points of adjustment for desk work and leaning back. Seat height, headrest, lumbar support and back support can be adjusted, and the chair includes 2D armrests and a tilt function.
SIHOO M18 Ergonomic Chair
- Adjustable headrest
- Adjustable lumbar and back support
- Mesh back
- Stated fit range of 5 ft 6 in to 6 ft 2 in
- 330 lb capacity
The M18 suits desk users who want to position both head and lower-back support. Check seat fit and arm clearance before choosing it for a full workday.
Pros
- Adjustable headrest, lumbar and back support
- Mesh back allows airflow
- 2D armrests
- SIHOO offers free replacement parts during its 3-year warranty period
Cons
- Stated height range excludes some shorter and taller users
- Seat depth adjustment needs confirmation if you require it
Its strongest use case is a desk setup where you want lower-back contact while working and head support during breaks. A headrest is less useful if it pushes your head forward when you type, so its position matters more than its presence.
The mesh back leaves room for airflow, while sponge fill provides the seat cushioning. A breathable back can help in a warm room, but it won't make every surface of the chair feel cool.
SIHOO describes support at the head, back, hips and hands. Those contact points only help when they meet your body comfortably, without forcing your shoulders up or shifting you toward the front edge.
Who is the SIHOO M18 best for?
The M18 best suits someone within SIHOO's 5 ft 6 in to 6 ft 2 in height range who wants to fine-tune support around a regular desk. It's especially worth considering if your current chair leaves your lower back unsupported or has a headrest in the wrong position.
Skip it if you're outside that range and can't confirm a suitable fit. Also look elsewhere if adjustable seat depth is essential, unless you first confirm that the M18 provides the adjustment you need.
What should you measure before buying the M18?
Measure seat fit and desk clearance before counting features. Your height alone cannot show whether the seat supports your thighs or whether the armrests let you pull close enough to work.
Start with a chair you already find comfortable, if you have one. Measure its usable seat width, seat depth and height from the floor to the top of the cushion, noting whether the cushion compresses much when you sit.
Use these checks to turn those measurements into a buying decision:
- Seat depth: Sit against the backrest and check for a small gap behind your knees. A seat that presses into the knee crease can encourage you to slide forward and lose back support.
- Seat width: Leave enough room for your hips without pressure from the arms. Measure the usable space between the armrests as well as the cushion.
- Seat height: Your feet should have firm support while your thighs rest comfortably. If desk height forces you to raise the chair, include a footrest in your setup plan.
- Desk opening: Measure under the desktop, including any drawer or support rail. Check clearance at the chair height you'll actually use.
- Working reach: Make sure you can bring the chair close enough to keep your elbows near your sides. A deep desktop can still put the keyboard too far away.
For a closer explanation of thigh support and leg room, see our guide to office chair seat height and seat depth.
A common mistake is buying a larger chair because it sounds more supportive. Extra depth can work against a shorter user by making it hard to reach the backrest while keeping both feet down.
How do you set up the M18 for desk work?
Set seat height first, then back support, arms and headrest. Work from your feet upward so later adjustments don't hide a poor starting position.
Begin with your feet supported and your hips resting toward the back of the seat. Check the space behind your knees before changing the lumbar support, since sliding forward changes where that support meets your back.
Next, position the lumbar area against your lower-back curve. Use enough contact to support your sitting position without a hard push that makes you arch or move away from the backrest.
Bring the armrests toward a position where your shoulders stay relaxed and your elbows remain near your body. Don't raise your shoulders to reach the pads or lean sideways to use them.
Position the headrest last and check it both upright and while leaning back. It should support you when you want contact, rather than steering your chin down toward your chest during keyboard work.
Our guide to adjusting an office chair explains the setup sequence in more detail.
If you still reach forward, move the keyboard and mouse closer before making another chair adjustment. A chair can't compensate for a screen that's hard to read or a mouse placed beyond comfortable reach.
Is the M18's capacity enough for your needs?
The M18 has a stated capacity of 330 lb, but capacity and seat room are separate checks. Choose a chair that meets your weight needs and gives you usable space between the arms.
Don't read a capacity figure as a promise of comfort or a prediction of service life. Your sitting position, daily use and the fit of the seat all affect whether the chair works for you.
Our guide to office chair weight capacity explains how to compare those numbers without confusing them with seat size.
SIHOO says the M18 passed a BIFMA test and a 1,136 kg static pressure test. The static figure is not a user weight limit and should never replace the chair's stated capacity.
For context on standards and scope, read our guide to what BIFMA means. Neither a standards claim nor a load figure tells you whether the headrest and lumbar support land in the right places.
How does the SIHOO M18 compare with alternatives?
Choose TRALT for a closer look at seat fit or FelixKing for arm clearance. The M18 remains worth considering when positioning both head and back support is your main priority.
When does TRALT make more sense?
TRALT deserves a closer look if you're below the M18's recommended height range. TRALT gives a stated fit range of about 5 ft 4 in to 6 ft 2 in, although leg length still determines whether the seat reaches low enough.
Its seat height adjusts from 17.7 in to 21.7 in, and its lumbar support adjusts in depth. That makes it easier to compare both floor reach and lower-back contact with your current setup.
TRALT also uses a molded foam seat. The brand claims the foam resists flattening, but choose cushion fit and support over promises about how long any seat will retain its feel.
Skip TRALT if its minimum height leaves your feet unsupported or its seat depth crowds the backs of your knees. A stated user height range doesn't override either problem.
When does FelixKing make more sense?
FelixKing suits a shared workspace where the chair's arms sometimes need to move out of the way. Flip-up arms can help you bring the chair toward a desk opening, provided the seat and base also clear it.
It combines a mesh back and foam cushion with adjustable lumbar support, height and tilt. Its stated capacity is 300 lb, lower than the other 2 chairs here.
Skip FelixKing if you need a higher capacity or can't confirm that its seat height fits you. Moving the arms upward solves an arm-clearance problem, but it doesn't solve a seat that's too high or too deep.
For another option within the same brand, see SIHOO M18 vs M57. If upholstery is your main concern, our guide to mesh versus leather office chairs explains the material and care trade-offs.
What should you check during assembly and the first few days?
Follow SIHOO's assembly instructions, then check fit at your actual desk. SIHOO describes an 8-step process, so organize the parts before starting and keep the manual within reach.
Work on a clear surface that protects the chair parts and your floor. Match the hardware to each step, and follow the manual's tightening order rather than forcing a screw that doesn't align.
Before sitting, check that the base, casters, seat and back connections are secure as directed. Try the controls gently so you know how to change height and tilt before settling into a work session.
Our guide to assembling an office chair covers preparation and common assembly mistakes.
During the first few days, change one setting at a time and note what improves. If you adjust the seat, lumbar support and armrests together, it's harder to tell which change helped or caused pressure.
SIHOO offers free replacement parts during its 3-year warranty period. It also offers free returns and refunds within 30 days for faults or other quality-related issues, so check the applicable terms before relying on a return for poor fit.
Keep your order details, manual and any support messages together. Clear photos of a damaged part or a short description of a faulty control can help you explain a problem to support.
How should you care for the chair and use it through the day?
Use gentle cleaning and regular checks to keep the chair ready for work. Follow SIHOO's care directions for cleaners and maintenance, especially around mesh, moving parts and the gas cylinder.
Remove loose dust from the mesh and seat with a soft brush or a suitable vacuum attachment. Avoid catching the mesh with sharp tools or soaking the cushion when dealing with a spill.
Check the casters for trapped hair and debris if rolling becomes uneven. Inspect accessible fasteners as the manual directs, and investigate new movement or noise rather than tightening every part at random.
Don't force a control that has stopped moving or attempt to open the gas cylinder. Contact support when a component no longer works as intended.
During the day, change position and get up regularly instead of trying to hold one posture for hours. Even a well-fitted chair should let you move between work, leaning back and standing breaks.
Should you choose the SIHOO M18?
Choose the SIHOO M18 if its seat fits and you want support you can position around your head and lower back. Before ordering, resolve any uncertainty about seat dimensions, arm clearance and the adjustments you personally need.
Choose TRALT if its known seat measurements and lumbar depth adjustment match your body more closely. Choose FelixKing if moving the arms out of the way is central to how you use the workspace.
If none meets your fit checks, keep comparing rather than accepting poor leg support or cramped seating. Our best ergonomic office chairs for a home office guide is the next place to look.
Sources
SIHOO's M18 information provides the chair features, recommended height range and support terms discussed here.
Frequently asked questions
What height is the SIHOO M18 designed for?
SIHOO recommends the M18 for people from 5 ft 6 in to 6 ft 2 in tall; that range is a starting point, since people of the same height can have different leg and torso lengths. Check foot support, space behind your knees and headrest position before committing.
Does the SIHOO M18 have adjustable lumbar support?
Yes, the SIHOO M18 has adjustable lumbar support, plus adjustments for seat height, headrest and back support. Position the lumbar support against the curve of your lower back without letting it push you toward the seat edge; change one setting at a time so you can judge the result.
How much weight can the SIHOO M18 support?
The SIHOO M18 has a stated capacity of 330 lb; that limit does not tell you how much room the seat provides or whether the armrests will feel restrictive. Check both capacity and seated fit, especially if you need a wider seat or plan to use the chair for long workdays.
Does the SIHOO M18 require assembly?
Yes, the SIHOO M18 requires assembly, which SIHOO describes as an 8-step process. Clear enough floor space to organize the parts, follow the supplied instructions and check each connection before sitting down; keep the manual and spare hardware together so you can refer to them when checking or maintaining the chair.
