How many square feet is a 10x10 room?
100 sq ft 9.3 m² · 3.05 × 3.05 m
A 10 × 10 ft room is 100 sq ft, which is 9.3 m²: multiply the two sides. In metres the room is 3.05 × 3.05 m. A single bedroom by the space standard for new homes (7.5 m² or more). A double bed fits, but the standard counts a double bedroom from 11.5 m².
By the standards the UK uses for new homes, a room this size is a single bedroom: a double bed goes in, but with little floor left round it. As a home office or a child's room it is a comfortable size.
The sum only holds for a true rectangle. Measure both pairs of walls, because few rooms are square, and add an alcove or a bay as its own small rectangle.
Worked out for A plain rectangular room, 10 × 10 ft wall to wall, which is 3.05 × 3.05 m. Change the numbers
The working
- Floor: 3.05 m × 3.05 m = 9.29 m²
- Total 9.29 m² = 100 sq ft (1 m² = 10.76 sq ft)
The rules, and their sources
Average room sizes in homes built since 2010
In LABC Warranty's 2018 analysis of 10,000 listings, the average living room in a home built since 2010 was 17.1 m², against 24.9 m² in the 1970s; the average bedroom was 13.4 m².
A published study Sources: Which? (Garber, 14 Apr 2018), Shrinking homes: the average British house is 20% smaller than in the 1970s (checked 31 October 2026); Statista, Average living room sizes in new British houses 1930–2020 (checked 31 October 2026).
Space standard: bedroom sizes
In the space standard a single bedroom is at least 7.5 m² and 2.15 m wide. A double or twin is at least 11.5 m²; one double is at least 2.75 m wide and every other double at least 2.55 m. A home for two or more has at least one double.
A published standard Source: DCLG, Technical housing standards: nationally described space standard (March 2015, notes added 19 May 2016), Table 1 and paragraph 10 (checked 31 October 2026).
Other room sizes
The same sum for the room sizes people ask about most, in both units.
| Room | Square feet | Square metres |
|---|---|---|
| 10 × 10 ft3.05 × 3.05 m this page | 100 sq ft | 9.3 m² |
| 10 × 12 ft3.05 × 3.66 m | 120 sq ft | 11.2 m² |
| 12 × 12 ft3.66 × 3.66 m | 144 sq ft | 13.4 m² |
| 12 × 14 ft3.66 × 4.27 m | 168 sq ft | 15.6 m² |
| 12 × 15 ft3.66 × 4.57 m | 180 sq ft | 16.7 m² |
| 15 × 15 ft4.57 × 4.57 m | 225 sq ft | 20.9 m² |
| 15 × 20 ft4.57 × 6.1 m | 300 sq ft | 27.9 m² |
Change the numbers
Your sizes will differ. The room size calculator opens with these numbers filled in: change any of them and the answer, the working and the drawing follow.
Editorial notes
Worked out by the Snuug team on 12 November 2026 with the same code as the room size calculator, so the two cannot disagree. Every rule cites its source, with the date we last checked it. A rule designers use is a convention, not a study.
Other sources the calculator draws on:
- The Licensing of Houses in Multiple Occupation (Mandatory Conditions of Licences) (England) Regulations 2018 (SI 2018/616), regulation 2, checked 31 October 2026
- MHCLG, English Housing Survey 2018-19, Size of English homes fact sheet, checked 31 October 2026
- Flooring Hut, What widths do carpets come in?, checked 31 October 2026
- B&Q, Metsä Wood primed MDF square skirting board, 2.4 m, pack of 4, checked 31 October 2026
- MDF Skirting World, The length option (3050 and 4200 mm), checked 31 October 2026
- Howarth Timber (Green, 14 Sep 2026), UK door sizes, checked 31 October 2026