When comparing three-seater sofas, separate overall width from the width available for sitting. Armrests and the frame take up room, so a longer sofa may not give you more space to sit. First narrow the options to sizes that fit your room, then compare seat width, depth, height, and how you actually sit.
Look for separate seat measurements
| Measurement | What it helps answer | What the number cannot tell you |
|---|---|---|
| Overall width, depth, and height | How much room will the sofa occupy? | Will three people feel comfortably spaced? |
| Seat width | How wide is the seating area? | Will each person have the space they want? |
| Seat depth | How deep is the seat from front to back? | Will the position suit you when leaning back? |
| Seat height | How high is the seat surface? | How far will the cushion compress under you? |
For an example, look at the specifications for the Korean market: IKEA's KIVIK three-seat sofa in Grann/Bomstad black, article 805.195.26, lists overall width 227 cm, depth 95 cm, and height 83 cm. Its seat dimensions are listed separately: width 180 cm, depth 60 cm, and height 45 cm. These figures apply to this particular version. IKEA Korea KIVIK 805.195.26 dimensions
The difference between its overall width and seat width is 227 − 180 = 47 cm. That is the difference between two published measurements. It does not establish that each armrest is exactly 23.5 cm wide: the structure and measurement locations would need confirmation.
We have used this sofa to show how to read the measurements; it is not a buying recommendation. Do not assume that another fabric, configuration, or regional version is identical. Availability, delivery, returns, and warranty in your country have not been checked here.
Can a longer sofa have a narrower seat?
The following candidates are invented for comparison. They are not actual product specifications or offers.
| Measurement | Fictional A | Fictional B |
|---|---|---|
| Overall width | 200 cm | 220 cm |
| Seat width | 168 cm | 165 cm |
| Difference between overall and seat width | 32 cm | 55 cm |
| Seat width divided by three | 56 cm | 55 cm |
B is 20 cm longer overall, but its seat is 3 cm narrower. So choosing B just because it looks bigger on the outside could leave three people with less seat space than expected.
Dividing the seat width by the number of people gives you a length to compare. It cannot tell you whether everyone will be comfortable. People need different amounts of space; the center cushion and the way someone leans on an arm also matter. The calculation does not establish a suitable seating capacity or guarantee comfort.
Wide arms are not automatically wasted space either. A wide armrest may be just what you want to lean on while reading. Decide whether maximizing seat width or having a particular armrest arrangement matters more to you.
Decide how your household will sit
Write down whether people usually sit side by side or whether one person mainly stretches out. Choose one or two situations that reflect ordinary use:
- Two people sit at opposite ends with the middle left free.
- Three people watch a screen at the same time.
- One person puts their legs up while another sits alongside.
- Someone reads while leaning against the back and an armrest.
If you already have a sofa or chairs, observe the positions people find comfortable. Separate “we need more seating space” from “one cushion feels uncomfortable.” Before replacing the whole sofa, ask whether the manufacturer offers an appropriate inspection or replacement part.
If you already have enough seating and a larger sofa would only narrow the walkway, a purchase can wait. Knowing what you want to change—such as “three of us cannot sit together comfortably”—helps you decide what to look for.
Try the seat depth in your usual sitting position
A deeper seat is not always a better fit. Try sitting the way you would at home. This guide does not suggest that there is one correct seat depth for everyone of a particular height.
If you can visit a store, try the positions you expect to use and record the following.
| Situation | What to note |
|---|---|
| Sitting with your back supported | Where the cushion meets your back; whether you keep shifting your legs |
| Taking your usual reading position | Whether the armrest works for you; whether another cushion is needed |
| Sitting alongside other people | Center-seat shape and the space each person occupies |
| Sitting down and standing up | Whether you can move comfortably and place your hands where you need support |
Use comparable conditions across candidates. If one needs extra cushions, record “works with these cushions” rather than treating it as an identical setup. A short store visit does not establish long-term durability or health benefits.
When buying online, ask where the seat-depth measurement starts and ends, whether the back cushions are in place, and whether options change the dimensions. If you cannot get an answer, leave the measurement unconfirmed instead of trying to work out an exact length from a photograph.
Decide what the sofa must fit before scoring your options
Check these three requirements to narrow down your choices:
- Placement: The full width and depth fit the usable space at home.
- Use: The seat dimensions and intended sitting arrangement have been checked, or the necessary questions have been answered.
- Configuration: The model, upholstery, legs, and cushions you checked match the order.
A sofa that fails the placement requirement is unsuitable for that location even if the seat width looks appealing. Check access separately with our furniture fit and delivery checklist. The seating comparison here does not establish that a sofa can reach the room.
Request costs for the same configuration. Check whether the quote includes the sofa, chosen cover or legs, delivery, assembly, and removal of existing furniture. Do not assume a fixed delivery charge or free removal without checking the destination and order terms.
On the product page, begin by writing down overall width and seat width separately, then investigate depth and your sitting arrangement. If a measurement is missing, mark it as a question for the seller.
Sources checked: September 8, 2026. AI assisted drafting and English localization from our Korean article. The guide uses published dimensions and original hypothetical comparisons. We did not test seating comfort or long-term durability.