Square Footage Calculator UK | Square Metre Calculator 2025
Calculate square metres (m²) and square feet (sq ft) for any room or space. Supports multiple shapes, unit conversions, and material calculations for UK property and construction projects.
Step 1: Select Shape
Step 2: Select Unit
Step 3: Enter Dimensions
Step 3: Enter Dimensions
Step 3: Enter Dimensions
Step 3: Enter Dimensions
Or enter diameter and divide by 2
Step 3: Enter Dimensions (L-Shaped Room)
Step 3: Enter Dimensions
Quick Area Conversion Reference
Essential conversions for UK property measurements:
| Square Metres (m²) | Square Feet (sq ft) | Typical UK Use |
|---|---|---|
| 1 m² | 10.76 sq ft | Small cupboard |
| 5 m² | 53.82 sq ft | Small bathroom |
| 10 m² | 107.64 sq ft | Single bedroom (basic) |
| 15 m² | 161.46 sq ft | Double bedroom |
| 20 m² | 215.28 sq ft | Living room (small) |
| 37 m² | 398.26 sq ft | Studio flat (minimum) |
| 50 m² | 538.20 sq ft | 1-bed flat |
| 70 m² | 753.47 sq ft | 2-bed flat |
| 100 m² | 1,076.39 sq ft | 3-bed house |
UK Room Size Standards & Building Regulations
Minimum and average room sizes according to UK Building Regulations and housing standards:
| Room Type | Minimum (m²) | Minimum (sq ft) | UK Average (m²) | Regulation |
|---|---|---|---|---|
| Single Bedroom | 6.51 m² | 70 sq ft | 7.5 m² | Housing Act 1985 |
| Double Bedroom | 11.15 m² | 120 sq ft | 13.4 m² | Housing Act 1985 |
| Living Room | N/A (guidance only) | N/A | 17.1 m² | HHSRS Guidance |
| Kitchen | 5.5 m² | 59 sq ft | 13.4 m² | HHSRS |
| Bathroom | 2.74 m² | 29.5 sq ft | 4.4 m² | Building Regs Part G |
| Studio Flat (1 person) | 37 m² | 398 sq ft | 40 m² | NDSS (England) |
| 1-Bed Flat (2 persons) | 50 m² | 538 sq ft | 55 m² | NDSS |
| 2-Bed House (3 persons) | 70 m² | 753 sq ft | 75 m² | NDSS |
| 3-Bed House (4 persons) | 84 m² | 904 sq ft | 95 m² | NDSS |
Key: NDSS = Nationally Described Space Standard (England only). HHSRS = Housing Health and Safety Rating System.
Area Calculation Formulas
The mathematical formulas used for calculating area of different shapes:
Rectangle / Square
For squares, this simplifies to Area = Side²
Triangle
Height must be perpendicular to the base (90° angle)
Circle
Where π (pi) = 3.14159... Radius = Diameter ÷ 2
Trapezoid
The two parallel sides are the bases; height is perpendicular distance between them
L-Shaped Room
Split the L-shape into two rectangles and add their areas together
How to Measure an L-Shaped Room
Divide L-shaped rooms into two rectangles, measure each section, then add the areas together.
Flooring & Paint Material Calculator
Use your calculated area to estimate materials needed:
Flooring Calculator
Paint Calculator
(2 × Length + 2 × Width) × Height. Then subtract window and door areas (typical door ≈ 1.9 m², typical window ≈ 1.2 m²).
Understanding UK Property Measurements: GIA vs NIA
GIA - Gross Internal Area
The total internal floor area measured to the internal face of external walls.
- Includes internal walls & partitions
- Includes columns and pillars
- Includes stairwells (each level)
- Used for: Building costs, valuations
NIA - Net Internal Area
The usable floor area excluding structural elements.
- Excludes internal walls
- Excludes structural columns
- Excludes stairwells and lift shafts
- Used for: Rentable space, office let
For EPC certificates: Total Floor Area is measured to the internal surface of external walls, similar to GIA but typically excludes unheated spaces like garages.
7 Essential Tips for Accurate Area Measurement
- Always measure twice: Take measurements at least twice and use the average. Small errors multiply when calculating area.
- Use consistent units: Don't mix metres and feet in the same calculation. Convert everything to one unit first.
- Measure at floor level: Walls aren't always vertical. Measure at skirting board height for floor area, not at eye level.
- Account for alcoves and recesses: Measure main rectangle plus any alcoves, bay windows, or recesses separately.
- Add wastage for materials: Always add 10-20% extra when buying flooring, tiles, or carpet to account for cuts and fitting.
- Check building plans if available: For properties over 10 years old, original building plans may be available from local council.
- Use a laser measure for accuracy: Laser distance measurers (from £20) are more accurate than tape measures for large rooms.
7 Common Area Measurement Mistakes to Avoid
- Measuring external dimensions: Property marketing sometimes uses external measurements which are 10-15% larger than actual internal floor space.
- Forgetting to subtract obstacles: When calculating flooring, remember to subtract fitted wardrobes, kitchen islands, and other permanent fixtures.
- Confusing m² with sq ft: 1 m² = 10.76 sq ft. A "50 sq ft" room is only about 4.6 m² - much smaller than it sounds!
- Not accounting for irregular shapes: Most rooms aren't perfect rectangles. Check for angles, curves, and projections.
- Measuring to wall centres for floorspace: Measure to the face of the wall, not the centre. Only use centre-to-centre for structural calculations.
- Including non-habitable areas: Garages, outbuildings, and conservatories may not count toward habitable floor area for EPC or planning purposes.
- Rounding too early: Keep full decimal precision until the final result to avoid cumulative rounding errors.
Frequently Asked Questions
To convert square metres (m²) to square feet (sq ft), multiply by 10.764. For example, 10 m² = 107.64 sq ft. Conversely, to convert sq ft to m², divide by 10.764 or multiply by 0.0929.
In the UK, property sizes are officially measured in square metres for EPC ratings and building regulations, but square feet is still commonly used by estate agents and in property listings.
Average UK room sizes vary by type:
- Living rooms: 17.1 m² (184 sq ft)
- Master bedrooms: 13.4 m² (144 sq ft)
- Kitchens: 13.4 m² (144 sq ft)
- Bathrooms: 4.4 m² (47 sq ft)
UK Building Regulations require single bedrooms to be at least 6.51 m² (70 sq ft) and double bedrooms at least 11.15 m² (120 sq ft).
In the UK, property size is measured using Gross Internal Area (GIA) or Net Internal Area (NIA).
GIA measures the total internal floor area including all internal walls and partitions. NIA excludes structural walls, stairwell voids, and other non-usable spaces.
For residential property, EPC certificates use the Total Floor Area measured in square metres, which is similar to GIA.
Calculate your room's square footage, then add wastage for cutting and fitting:
- Standard rooms: Add 10% wastage
- Complex shapes: Add 15% wastage
- Diagonal installation: Add 20% wastage
Most flooring is sold in packs covering 1.5-2.5 m². Divide your total area (including wastage) by the pack coverage to find how many packs you need. Always round up.
UK Housing Standards require minimum room sizes:
- Single bedroom: 6.51 m² (70 sq ft) with at least 2.15m width
- Double bedroom: 11.15 m² (120 sq ft)
- Studio apartment (1 person): 37 m² (398 sq ft)
- 1-bed flat (2 persons): 50 m² (538 sq ft)
These standards are enforced through the Housing Health and Safety Rating System (HHSRS) and the Nationally Described Space Standard (NDSS) in England.
For irregular rooms, divide the space into regular shapes:
- L-shaped rooms: Split into two rectangles, calculate each, then add together
- Rooms with alcoves: Calculate main rectangle plus each alcove
- Bay windows: Add main area plus bay (rectangle or triangle depending on style)
- Curved walls: Approximate as a series of triangles or use circle segment formula
For complex shapes, sketch the room on graph paper first to identify the component shapes.
Standard UK paint coverage is approximately:
- Per litre (one coat): 10-12 m²
- Per litre (two coats): 5-6 m²
- 2.5L tin (two coats): 12-15 m²
- 5L tin (two coats): 25-30 m²
Textured surfaces, porous walls, and painting dark over light colours may require more paint. Always check the tin for specific coverage rates.
GIA (Gross Internal Area): Measures the entire internal floor area within external walls, including internal walls, columns, and stairwells.
NIA (Net Internal Area): Excludes these structural elements, measuring only usable floor space.
GIA is typically 10-15% larger than NIA. GIA is used for building costs and valuations, while NIA is better for understanding usable space. RICS (Royal Institution of Chartered Surveyors) provides official measurement standards for UK property.
Official UK Resources
Authoritative sources for UK property measurement and building standards:
RICS Property Measurement
Royal Institution of Chartered Surveyors - official standards for measuring buildings in the UK.
Visit RICS websiteGOV.UK Housing Standards
Official government guidance on Nationally Described Space Standards (NDSS) for new homes.
View Space StandardsPlanning Portal
Official UK government guidance on building regulations, planning permission, and floor space requirements.
Visit Planning PortalEPC Register
Find and understand Energy Performance Certificates, which include official floor area measurements.
Search EPC RegisterLABC (Building Control)
Local Authority Building Control - guidance on building regulations and room size requirements.
Visit LABC websiteWhich? Home Buying Guide
Consumer guidance on understanding property sizes and what to look for when measuring homes.
Visit Which?About This Calculator
This free Square Footage Calculator has been developed specifically for UK users who need to measure and convert floor areas. Whether you're measuring rooms for flooring, calculating wall space for paint, or understanding property sizes for buying or renting, this tool provides accurate calculations using industry-standard formulas.
The calculator supports multiple shapes including rectangles, triangles, circles, L-shaped rooms, and trapezoids. It converts between metric (square metres) and imperial (square feet) measurements, and provides material estimates for flooring and paint projects.
All calculations are performed locally in your browser for instant results. No data is stored or transmitted. This calculator is regularly updated to reflect current UK building regulations and housing standards.
Pro Tips for Accurate Results
- Double-check your input values before calculating
- Use the correct unit format (metric or imperial)
- For complex calculations, break them into smaller steps
- Bookmark this page for quick future access
Understanding Your Results
Our Square Footage Calculator provides:
- Instant calculations - Results appear immediately
- Accurate formulas - Based on official UK standards
- Clear explanations - Understand how results are derived
- 2025/26 updated - Using current rates and regulations
Common Questions
Is this calculator free?
Yes, all our calculators are 100% free to use with no registration required.
Are the results accurate?
Our calculators use verified formulas and are regularly updated for accuracy.
Can I use this on mobile?
Yes, all calculators are fully responsive and work on any device.