Dining room · table sizing
Dining table size calculator.
Enter how many people need to sit, the shape and your room. The calculator uses 24 in of table per person to give the minimum length (or round diameter), then the largest table your room allows with 36 in of clearance on each side. Inches and feet or centimetres and metres. Runs in your browser; nothing is sent or stored.
Seats and room
Table size
Worked example
Six people, a rectangular table 36 in wide, 24 in per person and a 14 x 12 ft (168 x 144 in) room. Seating on the long sides only: 6 / 2 = 3 people per side, so length = 3 x 24 = 72 in (6 ft). The room limit is 168 - 72 = 96 in long by 144 - 72 = 72 in wide, so a 72 x 36 in table fits. A round table for six needs 6 x 24 / pi = 45.8 in across, and the room allows 72 in.
Method
Plain arithmetic. Rectangular: the people on each long side = the seats not at the ends, divided by two and rounded up; length = that number x the space per person. Round: the table edge is the circle circumference, so diameter = seats x space per person / pi (this is the geometry of the 24 in rule, not a figure the guides print). Room limit: the largest table is the room length and width minus 72 in, which is 36 in of clearance on each side (the Ash Deco 72 in rule).
Rules of thumb. The 24 in per person comes from Pop Maison and The Furniture Mall, who both say at least 24 in. Ash Deco explains the 36 in as about 18 to 24 in for a chair to pull back plus 12 to 18 in for someone to walk behind it; allow more where the space is also a walkway. Pop Maison also publishes round table size ranges by number of seats, which are wider than the minimum this tool computes.
Rule of thumb, not a standard. These are design rules of thumb from published decorating guides, not building codes or standards. Treat the result as a starting point and tape it out in the room before you buy or drill. Results are shown in both imperial and metric. Conversions use 1 in = 2.54 cm and 1 ft = 0.3048 m.
Sources, each opened 2026-10-08:
- What Size Dining Table Do I Need (Pop Maison): at least 24 in of table per person and round table size ranges by seats.
- Dining Table Size Guide: Will It Fit Your Room? (72" Rule) (Ash Deco): max table = room - 72 in, 36 in of clearance each side.
- What Size Dining Table Do I Need? | The Furniture Mall (The Furniture Mall): 24 in per person and 36 in between table and walls or furniture.
- NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically (NIST): lists 1 inch = 2.54 cm, 1 foot = 0.3048 m and 1 footcandle = 10.76391 lux.
Frequently asked questions
How much table space does each person need?
Pop Maison recommends at least 24 in per person and The Furniture Mall says the same. The calculator uses 24 in by default; you can change it if you want a more generous or tighter setting.
How much clearance should I leave around the table?
Ash Deco gives a 72 in rule: the table can be at most the room length and width minus 72 in, because you need 36 in of clearance on each side, made up of about 18 to 24 in for the chair to pull back and 12 to 18 in to walk behind. The Furniture Mall also gives a minimum of 36 in to walls or furniture.
How big should a round dining table be?
The calculator divides seats x space per person by pi, which is a minimum from the circle circumference. Pop Maison lists larger ranges, for example 44 to 52 in across for up to six and 54 to 72 in for up to eight, so treat the result as a minimum.
How wide should a rectangular dining table be?
The cited guides do not set one required width. You enter your own and the calculator only checks it against the room.
How are seats at the ends counted?
If you choose one person at each end, those two seats are taken out of the side count and the remaining people are split across the two long sides. The end seats assume the table is at least one space per person wide.