Everyday Life⏱ 4 min read
How to Calculate Square Footage (and Square Metres) of Any Space
Whether you're buying flooring, carpet, or comparing rental prices, accurate area calculation is essential. Here's how to measure any room shape — including L-shapes, alcoves, and awkward spaces.
Measuring square footage (or square metres) correctly can save you from ordering too little flooring or overpaying for a property based on incorrect quoted sizes. Here's a complete practical guide.
Square Footage vs Square Metres
1 square metre = 10.764 square feet
1 square foot = 0.0929 square metres
Convert sq ft → sq m: divide by 10.764
Convert sq m → sq ft: multiply by 10.764
Example: 350 sq ft apartment
= 350 ÷ 10.764 = 32.5 m²
Basic Rectangle or Square Room
Area = Length × Width
Example: 4.5m × 3.8m room
= 17.1 m² (or 184 sq ft)
L-Shaped Rooms
Method: divide into two rectangles, add areas together.
|---4m---|
_____| |
| \ A |
| B \ |
|_______|_____|
3m 2.5m
Measure the full outer dimensions:
Total area = Area A + Area B
Or: total outer rectangle − missing corner
= (6m × 4m) − (3m × 1.5m) = 24 − 4.5 = 19.5 m²
Always sketch the room and label measurements before calculating.
Rooms With Alcoves and Bay Windows
Add alcoves and bay windows to the main rectangle:
Main room: 4m × 3.5m = 14 m²
Alcove: 1.2m × 0.8m = 0.96 m²
Bay window recess: 2m × 0.6m = 1.2 m²
Total: 14 + 0.96 + 1.2 = 16.16 m²
For flooring: include these areas — they need covering.
For wall area: measure each wall individually.
Triangular Spaces
Area = 0.5 × Base × Height
Loft conversion triangular section: base 4m, height 2m
= 0.5 × 4 × 2 = 4 m²
For Flooring: Add 10% Wastage
Actual order = Calculated area × 1.10
Flooring is cut from fixed-width rolls or boards.
Wastage from cuts, pattern matching, and irregular rooms
is typically 8–15%.
For diagonal laying pattern: add 15% instead of 10%
For large pattern repeat: add the repeat length waste separately
How Property Floorplans Are Measured
In the UK, residential property floor area is typically measured to the internal faces of the external walls (gross internal area or GIA). This includes all rooms, hallways, and built-in storage, but excludes garages and external walls. Estate agents must follow RICS measuring standards — but errors are common. For any major purchase, having an independent survey that includes floor area measurement is worthwhile.
Internal area check: measure every room individually,
add together, and compare to the advertised floor area.
A 5–10% discrepancy is worth querying with the agent.