An armchair has five main parts: the frame, the seat, the back, the arms and the base. Each one affects how the chair feels after an hour of reading, how it looks from across the room and how well it copes with daily use. This guide goes through them one by one, with the typical dimensions to check before you choose a model from our armchair collection or ask for custom dimensions.
Every Sitdesign armchair is handmade in our own factory in Büyükçekmece, Istanbul, so the notes below also describe what goes inside our own pieces.
The frame: kiln-dried beech
The frame is the part you never see, and it decides whether a chair stays square and quiet. Our upholstered frames are made of kiln-dried beech. Beech is a dense hardwood that holds dowels, screws and staples firmly, which matters where the arms and back meet the seat rail. Those joints take most of the load when someone leans back or pushes up to stand.
Kiln-drying lowers the moisture content of the timber before it is cut. Wood that is still drying after assembly can shrink and twist, which loosens joints and causes creaks. A common test for any armchair is to lift one front corner: a stiff frame rises as one piece, while a weak one flexes and the opposite leg stays on the floor.
The seat: HR foam over springs
Comfort starts with the seat construction. Our armchairs have sprung seating with high-resilience (HR) foam on top. The springs give a supportive base that spreads your weight; the HR foam recovers its shape quickly after you stand up, so the seat keeps its line instead of forming a hollow where someone always sits.
Three seat dimensions are worth measuring:
- Seat height: typically 40–45 cm from the floor to the top of the cushion. Lower seats of 38–42 cm feel more relaxed; higher ones are easier to get out of.
- Seat depth: a usable depth of 50–55 cm suits reading and conversation; 55–65 cm suits a lounge chair, usually with a back cushion.
- Seat width: 50–60 cm between the arms is common for one person; a wider seat lets you sit sideways or tuck your legs up.
As a rough rule, your feet should rest flat on the floor with your thighs close to horizontal. If you are much taller or shorter than average, this is where custom dimensions on request make the most difference.
The back: height, angle and shape
The back sets both posture and silhouette. A low back, with an overall chair height of around 70–80 cm, keeps sight lines open in a living room and sits well next to a sofa. A high back of 95–110 cm supports the head and shoulders and creates a more enclosed reading corner.
The angle between seat and back is the second variable. Around 100–105 degrees gives an upright position for reading or a desk-side chair; 105–115 degrees is more relaxed. A back can be fixed and tightly upholstered, or carry a loose cushion that you can plump and turn. Some designs join the back and arms into one continuous shell, sometimes upholstered in a contrasting colour, like the armchair we showed at İSMOB 2016 at TÜYAP.
The arms: height and width
Arms carry your elbows and help you stand up, so their height matters more than their shape. A common range is 18–25 cm above the compressed seat, or about 55–65 cm from the floor. Lower arms suit a relaxed chair; higher arms make a chair feel more enclosing.
Arm width changes the footprint. Slim arms of 8–12 cm keep an armchair compact; broad, padded arms of 15–25 cm add comfort and presence, but they also add overall width without adding seat space. When a floor plan is tight, compare the overall width with the seat width: two chairs with the same 85 cm footprint can offer very different sitting space. The same logic applies to sofas, as we explain in The Anatomy of a Sofa.
The base: legs, plinth or skirt
The base decides how heavy the chair looks. Exposed legs that raise the body 12–18 cm off the floor show more floor, make a small room look larger and let you clean underneath. A plinth or upholstered base close to the floor gives a more solid, grounded look and suits a chair placed against a wall or in a large room. If you use a robot vacuum, check the leg height: many need about 10 cm of clearance.
Look at the overall size as well. A typical lounge armchair is 75–95 cm wide and 80–95 cm deep. Allow roughly 45–60 cm between the chair and a coffee table, so you can reach a cup and still walk past.
The cover: leather or fabric
The upholstery is the part you touch every day. We use genuine leather only, in 76 colours across 12 colour families, and Italian leathers form our top leather group. Fabric upholstery is also possible, and we accept customer's own material (COM). Our leather materials page explains the options, and we send leather samples on request so you can compare them in your own light.
To see how these parts come together in finished models, compare the Jackson armchair and the Lichfield armchair. Look at the seat height, the arm width and the base of each, and note which proportions suit your room and the way you sit.
If you have a model in mind, or a measurement that has to fit, send us the room size and the dimensions you need. Upholstered pieces take 3–4 weeks to make. Contact us for leather samples and a quote.
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