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Dining table size calculator

Will this rectangular table fit the usable dining area and the people who sit there?

Before you startMeasure from the nearest fixed obstacle on each side, not automatically from wall to wall.
Step 1

Add your measurements

Compare the exact table with the room left after clearance and a simple seat-length screen.

Example numbers are loaded

Replace each example with your own values. The result on the right updates as you type.

Add the tableUse regular seats and the full top dimensions shown for the exact product.
Measure the usable dining zoneStop at cabinet faces, sideboards, radiators, door swings, islands, or another protected route.
Choose the room around itUse the space your actual chairs and circulation need; the calculator applies it on every side.

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Example resultLooks good on paper

The table passes both first checks

After subtracting 90 cm on every side, the largest rectangular footprint is 260 x 180 cm. The seat-length screen for 6 regular seats is 180 cm.

Change the sample values to turn this into your estimate.
Table entered
180 x 90 cm
Maximum footprint
260 x 180 cm
Seat-length screen
180 cm
Tightest room margin
80 cm
Dining table planning diagramA proportional schematic based on the entered values. It is not a construction drawing.
Proportional planning schematic - verify all dimensions on site.

Before you buy or start work

  • Use the exact full length and widest top dimensions, including an extension leaf.
  • Check usable edge between table legs and test any end seats or armchairs.
  • Tape the table and pulled-out chair positions, then walk the real route behind an occupied chair.
Method

What this result assumes

The table is a rectangle aligned with the usable dining zone.

The seating screen uses about 60 cm of long table edge per regular seat, divided between two long sides.

The same user-selected clearance is applied on all four sides.

Limitations

What it cannot confirm

Table legs, bases, aprons, end seats, armchairs, and individual access needs can reduce usable seating.

Round, oval, angled, and irregular dining zones are not modeled.

An active kitchen or pass-behind route may need more space than the selected uniform clearance.

This is a planning estimate, not a building-code, safety, installation, or delivery guarantee.

Confirm product-specific requirements with the manufacturer, installer, retailer, or qualified trade.

Formula 1.1.0Reviewed 2026-08-04General planning assumptions
Read category methodology
Check table and room

One table has to pass two limits: people and space.

This calculator compares an exact rectangular table with two independent constraints. The room check subtracts the same user-selected clearance from all four sides of the usable dining zone, then compares the table top with the rectangle left over. The seating check compares the table length with a simple allowance of about 60 cm for each regular seat divided between the two long sides.

Neither check is a promise of comfort or capacity. A table can fit the remaining floor rectangle while its legs block chairs, and a shorter table may still seat people at the ends when the manufacturer designed it that way. RoomFact shows the two screens separately so a product seating chart cannot hide a circulation problem and a generous room cannot make an unsuitable base disappear.

Worked example

A six-seat table beside a sideboard

After a sideboard is excluded, the usable dining zone measures 365 cm long by 260 cm wide. The candidate table is 180 x 90 cm, and the household chooses 90 cm of clearance on every side.

Regular seats
6
Table entered
180 x 90 cm
Usable dining zone
365 x 260 cm
Selected clearance
90 cm each side
Seat-length screen
180 cm
How RoomFact reads it

Subtracting 90 cm twice leaves a maximum footprint of 185 x 80 cm. The table length meets the 180 cm seat-length screen and leaves 5 cm along the room, but the 90 cm table width is 10 cm wider than the calculated maximum. RoomFact therefore returns a room-fit review rather than a pass.

  • The conflict comes from width, not seating length. Shopping for a shorter table would not solve this particular result.
  • Reducing the clearance is a deliberate room-use tradeoff, not a mathematical fix. The actual chair and the sideboard route have to prove that smaller distance works.
  • Removing or relocating the sideboard, choosing a narrower top, or changing table orientation creates a new usable zone and should be calculated as a separate scenario.
01

Measure the usable zone from real obstacles

Start with the dining area, then stop each dimension at the nearest surface that people or chairs cannot use. Measure from a sideboard or cabinet face rather than the wall behind it. Include radiator projections, island overhangs, door swings, and any route that must remain open. If the boundary changes along one side, use the tightest relevant rectangle for this calculator and sketch the irregular remainder separately.

Label the long and short directions instead of relying on a room name. The calculator assumes the table length follows the usable-zone length. To test a ninety-degree rotation, swap the zone dimensions and run another result. Do not silently choose whichever orientation passes; the rotated table still has to work with doors, lighting, serving access, and the path into the room.

02

Choose clearance for the activity behind the chair

Retailer guides commonly illustrate roughly 80 to 90 cm between a table and a wall or cabinet for chair use. IKEA illustrates a larger 120 cm condition beside an active kitchen run. Those are planning references, not universal requirements. A deep upholstered chair, frequent pass-behind route, mobility aid, serving pattern, or local accessibility rule can create a different requirement.

The calculator applies one clearance to every side because that keeps the arithmetic understandable. If one side needs more, use that larger number for a conservative first screen or calculate the sides manually. Then place the actual chair at the proposed table edge, sit in it, and have another person perform the real activity behind it. The lived test decides whether the selected clearance is credible.

03

Read the room screen and seat screen separately

The maximum footprint is usable-zone length minus two clearances by usable-zone width minus two clearances. It is a boundary, not a recommended table size. The tightest room margin identifies the smaller surplus; when the table is too large, the result names the controlling length or width shortfall so the next comparison addresses the right dimension.

The seat-length screen uses 60 cm per regular seat and divides the count between two long sides, rounding up for an odd number. It does not award seats at the table ends. That makes the calculation transparent but intentionally simple. A verified manufacturer seating plan may use end chairs, a pedestal, or a different edge allowance; compare that evidence with the result instead of changing the seat count to force a pass.

04

Replace every example with the exact product

Enter the widest top dimension and the longest state you intend to test. For an extendable table, save one result closed and another fully extended. Check where leaves are stored, where extra chairs wait, and whether the extended position blocks a kitchen, doorway, or primary route. A normal-day fit and a guest-day fit are different operating plans, and both can be valid when the tradeoff is explicit.

Tape the complete top outline, then mark leg or pedestal positions from the product drawing. Set the actual chairs at their occupied and pulled-out lines, open nearby doors and drawers, and walk behind a seated person. Confirm delivery access separately. The browser result narrows the shortlist; the exact base, chairs, people, route, and applicable requirements determine the final purchase.