Standard Sizes for Custom and DIY Furniture Builds: Seating
Designing your own furniture is easy… Any idea or “dream” piece can be a reality including knock-off variations of designs from catalog retailers. Most retailers will provide dimensions of the piece with consistent sizes straight across the board regarding table heights, seat heights, etc. I have compiled a list of standard sizes for custom and DIY furniture builds (for seating) based on the furniture industry so that the piece you create looks like it came straight off of a showroom floor!
In order for a dining table to be a comfortable height when seated, the chair has to also be at the right height. The perfect seat is 18″ from the floor to the top of the seat. The width can vary, however, depending on the style of the chair but the seat is usually 18″ to 22″ square. The back can be whatever height is desired to 22″ from the seat (which stops at about shoulder height for the average person) to no back at all (a bench). The angle of the back is also important to the comfort of the chair. In a dining chair, the angle is generally 5°.
Sofas & Loveseats
These are usually the most comfortable seats in the house but still have the same seat height as a regular chair which is 18″ from the floor to the top of the seat or cushion. (Always keep the thickness of the cushion in mind when designing an upholstered chair, sofa or loveseat!)
The back, however, can be one of three angles: 5° for a more formal setting, 10° for everyday seating and 15° for the ultimate in comfort. The back height should be enough that one can easily lean back and relax without straining: generally measuring 22″ from the top of the seat cushion to the top of the back.
The arm height is critical, too. The arms have to be at height that will be comfortable without being awkward, and is generally 26″ to 28″ from the floor to the top of the arm (or 8″ to 10″ above the top of the cushion).
There is a standard for the length of the sofa but I say if you’re designing it yourself, it is a matter of personal preference and how it will fit in your space. The seat depth ranges from 22″ to 24″ from the front to the front face of the back.
The length of a bench is entirely up to the designer or builder. It may be a bench for a dining table, for an entryway or for a front porch, so the length just has to fit the space. The seat height is the standard 18″ from the floor to the top of the seat with the overall seat depth ranging from 14″ to 16″.
Conversational seating can be classified as wingback chairs, recliners, club chairs, side chairs, etc. Each of these styles will also have an 18″ seat height from the floor to the top of the seat cushion. They will also vary in width and depth from 22″ square to 24″ square, depending on the desired level of comfort.
The back height will vary with the style of the chair: wingback chairs and recliners are generally 30″ from the top of the seat cushion to the top of the back (so that the head can rest comfortably on the back), club chairs have a back that will sit much lower which is generally 18″ from the top of the seat to the top of the back (about shoulder blade height), and side chairs will measure 22″ to 25″ from the top of the seat to the top of the back.
I have created a handy spreadsheet listing the seating type with the corresponding seat height, seat width and depth, back height, etc. for the standard sizes for custom and DIY furniture builds (for seating only) to keep as a reference when designing custom furniture. Have questions? Leave a comment below!