Measure across the widest part of your hips and thighs while sitting down, then add 2–3cm. That total is your seat width. If the number lands between two standard sizes, go up rather than down — but only by one size.
Seat width is the distance between the inside faces of the two armrests, not the width of the whole chair. A 45cm seat on a self-propelled wheelchair usually means an overall width closer to 62–65cm, which is the number that matters for doorways.
How to measure, step by step
- Sit on a firm, flat chair — a dining chair, not a soft sofa. Feet flat on the floor, knees at about a right angle.
- Wear normal clothes. If the chair will be used outdoors in winter, wear the coat you'd actually wear.
- Measure across the widest point of your hips or thighs, whichever is wider, with a tape held horizontally and level. Don't pull it tight — rest it against the body.
- Add 2–3cm. That's roughly a flat hand's thickness of clearance on each side, so you're not pressed against the armrests.
- Round to the nearest available size. If you're between sizes, choose the larger one.
A quick sanity check once the chair arrives: you should be able to slide a flat hand down each side between your hip and the armrest, but not make a fist.
Wheelchair seat width chart
New Zealand suppliers quote seat widths in both centimetres and inches, and the two don't always line up neatly. These are the common sizes:
| Seat width | Imperial | Suits hip measurement of roughly |
|---|---|---|
| 40cm | 16" | up to 37cm — petite adult |
| 43cm | 17" | up to 40cm — small adult |
| 45–46cm | 18" | up to 43cm — average adult (the most common size) |
| 50–51cm | 20" | up to 48cm — larger adult |
| 56cm | 22" | up to 53cm — bariatric / heavy-duty |
Children's chairs use 30cm (12") and 35cm (14") seats. Sizing a child's wheelchair is a job for an occupational therapist — growth, posture and seating support all come into it, and a chair that merely fits isn't the same as one that fits properly.
What goes wrong if the seat is too narrow
- Pressure on the outside of the hips and thighs, which is a common site for pressure areas
- Rubbing and bruising against the armrests or side panels
- Genuinely difficult transfers — getting in and out becomes a squeeze
- No room for a coat, a cushion, or the person's own hands beside them
What goes wrong if the seat is too wide
- Leaning. With nothing to sit against, people slump to one side, and over months that becomes a fixed posture
- Harder to self-propel. The rear wheels sit further out, so the shoulders work at a wider, weaker angle — a real cause of shoulder pain
- Doorways. Every extra centimetre of seat width is an extra centimetre of overall width
- Heavier and bulkier to lift into a car
Too wide is the more common mistake, and people rarely connect the resulting shoulder pain or slouch back to the chair.
Five things that change the fit
- A cushion adds width. Most wheelchair cushions are made to the seat size, but a bulky pressure-relief cushion can effectively narrow the space you sit in. If you know you'll use one, mention it when you're choosing a size.
- Winter clothing. A heavy coat can add 4–5cm. Measure in it if the chair is mainly for outdoor use.
- Body shape changes. Weight loss or gain, swelling, and post-surgery changes all matter. If a big change is expected, say so before ordering.
- Doorways come first. Measure the narrowest doorway in the house, and the bathroom especially. Compare that with the chair's overall width and leave at least 2cm spare.
- Seat depth and height matter too. Seat depth should leave a 2–3 finger gap behind the knee. Seat height should let the feet rest flat on the footplates with thighs supported along their length.
Seat width on our wheelchairs
Most of our range is offered in more than one seat width. The Freiheit Freedom Manual comes in 40cm, 45cm and 50cm; the X-Lite Manual and X-Lite Transit in 43cm and 46cm; the Vermeiren Jazz in 46cm and 50cm. For larger users the Titan Heavy-Duty is available in 510mm and 560mm.
Seat width isn't the only decision — read our guide to transit vs self-propelled wheelchairs as well.
Does the same measuring apply to lift chairs and shower chairs?
The principle does — measure the widest point across the hips while seated — but the allowances differ. Lift chairs are measured between the arms and are generally chosen to fit more snugly than a wheelchair, because side support is part of what makes standing up easier. Our lift chair guide covers sizing alongside motor choice.
Wheelchair seat width FAQs
How do I measure for a wheelchair seat width?
Sit on a firm chair with your feet flat on the floor, and measure across the widest part of your hips or thighs with a tape held level. Don't pull it tight. Add 2–3cm to that measurement and round to the nearest available seat width, going up rather than down if you're between sizes.
What is the standard wheelchair seat width?
In New Zealand the most common adult size is 45–46cm (18 inches), which suits hips measuring up to about 43cm. Standard sizes run from 40cm (16") for a petite adult through to 56cm (22") for heavy-duty and bariatric chairs.
Is it better for a wheelchair seat to be too wide or too narrow?
Neither is good, but slightly too wide is usually safer than too narrow, because a narrow seat presses on the hips and raises the risk of pressure areas. Don't overdo it — a seat more than about 5cm too wide causes leaning, poor posture, shoulder strain when self-propelling, and trouble getting through doorways.
Does seat width mean the total width of the wheelchair?
No. Seat width is measured between the inside faces of the armrests. The overall width of the chair is larger — on a self-propelled wheelchair, typically 17–20cm more once the rear wheels and handrims are counted. Use the overall width when you're checking whether the chair fits through your doorways.
How much room should there be between my hips and the wheelchair armrests?
About 1–1.5cm each side, so roughly 2–3cm in total. A good check is that you can slide a flat hand down each side between your hip and the armrest, but not a closed fist.
What wheelchair seat width do I need for a 100kg person?
Weight alone doesn't determine seat width — body shape does. Two people at 100kg can need quite different seats. Measure across the hips while seated and add 2–3cm. Do check the chair's weight rating separately: standard wheelchairs are commonly rated to 100–115kg, so at 100kg you may want a heavy-duty frame for durability even if a standard seat width fits.
Shop our full range of wheelchairs →
Not sure which size to order? Contact our NZ team with your measurement and we'll tell you honestly which chair fits — it's a lot cheaper than returning one. Every order comes with fast NZ delivery, a 30-day returns policy and local after-sales support.