Square Footage Calculator

Introduction

Calq.’s Square Footage Calculator helps you quickly measure the area of rooms, yards, and projects. It handles rectangles, triangles, and circles; then adds them up for a total area. It is ideal for homeowners, renters, real estate agents, contractors, landscapers, and DIYers planning flooring, painting, turf, mulch, pavers, and more. The tool uses feet (ft) and inches (in) as primary units, and also supports meters (m) and yards (yd).

How it works

Choose your unit system: feet/inches, meters, or yards.
Select a shape: rectangle, triangle, or circle.
Enter the shape’s dimensions:
- Rectangle: length and width
- Triangle: base and height (height must be perpendicular to the base)
- Circle: radius (half the diameter)
Add the shape. Repeat for as many areas as you have.
If you have cutouts (for example, a stairwell or island), measure them and subtract their area from your total.
Review the results: area per shape and the combined total. Totals appear in square feet and are also shown in square meters, square yards, and acres.

Inputs explained

Unit system
- Feet and inches (default): best for most U.S. projects.
- Meters: common in technical specs or imported products.
- Yards: often used for carpet and landscaping.
Shape type
- Rectangle: most rooms, patios, decks, and straight walls.
- Triangle: gables, roof sections, bay-window segments, and odd corners.
- Circle: round patios, planters, curved bays. For semicircles and quarter circles, use the circle formula with half or quarter of the result.
Dimensions
- Length and width (rectangle), base and perpendicular height (triangle), radius (circle).
- Inches are converted to feet automatically (12 in = 1 ft). If you have a diameter, divide by 2 to get the radius.
Multiple areas
- Add each distinct area as its own shape. The calculator sums everything to a grand total.

Results and interpretation

Area per shape: shows how much each room or feature contributes to the total. Useful for allocating materials by room.
Total area in square feet (sq ft): the main result for most U.S. projects.
Total area in square meters (sq m): helpful for products sold in metric.
Total area in square yards (sq yd): useful for carpet, sod, and some landscaping.
Total area in acres: helpful for lots and larger parcels (1 acre = 43,560 sq ft).
Rounding: small rounding differences can occur; measure carefully and add a sensible waste factor for ordering materials.

Method and assumptions

Core formulas
- Rectangle area = length × width
- Triangle area = 0.5 × base × height (height is perpendicular to base)
- Circle area = π × r² (π ≈ 3.14159; r is radius)
Composite shapes
- Complex spaces are approximated by splitting into rectangles, triangles, and circles. Sum all parts to get the total. Subtract cutouts separately.
Unit conversions (internal)
- The calculator converts all inputs to feet, computes area, then converts results:
  - 1 ft = 12 in
  - 1 yd = 3 ft → 1 sq yd = 9 sq ft
  - 1 m = 3.28084 ft → 1 sq m = 10.7639 sq ft
  - 1 acre = 43,560 sq ft
Scope and limits
- This tool computes area, not volume. For materials sold by volume (e.g., mulch in cubic yards), you will also need depth.
- Results reflect your measurements; building codes, appraisal standards, and listing rules vary by region.

Real-world uses in real estate, construction, and home improvement

Flooring and tile: estimate sq ft or sq yd for hardwood, laminate, tile, carpet, and underlayment. Add waste for cuts and pattern matching.
Painting: for floors and ceilings, use area directly. For walls, compute wall area as height × perimeter (minus windows/doors). Coverage per gallon varies by paint and surface; check the product label.
Landscaping: plan turf, pavers, gravel, and planting beds. Convert to acres for larger lots.
Real estate: estimate home square footage for planning. Definitions of gross living area (GLA) and whether to include garages, basements, or porches vary. Consult local guidelines for official measurements.

Tips and strategies

Measure twice: use a tape measure or laser distance meter. Record feet and inches separately to reduce conversion mistakes.
Break it down: divide irregular rooms into simple shapes. Use triangles for corners and circles for curved bays.
Use perpendicular height for triangles: do not use a sloped edge as the height unless it is perpendicular to the base.
Convert diameter to radius: radius = diameter ÷ 2. For a semicircle, area = 0.5 × π × r²; for a quarter circle, area = 0.25 × π × r².
Subtract cutouts: closets you are not flooring, stair openings, islands, and fireplaces can be removed from the total.
Plan for waste:
- Tile and LVP: often 10% (up to 15% for diagonal or complex layouts).
- Hardwood: 10-15% depending on board width and pattern.
- Carpet: discuss seam layout with your installer to optimize waste.
- Paint: coverage varies widely; add extra for multiple coats, porous surfaces, and touch-ups.
Keep records: sketch a quick plan with dimensions. Label each shape so you can cross-check quantities with suppliers.

Example calculations

Example 1: rectangular room (flooring)

Room size: 12 ft 6 in by 15 ft.
Convert to decimal feet: 12 ft 6 in = 12.5 ft.
Area = 12.5 ft × 15 ft = 187.5 sq ft.
Conversions:
- Square meters: 187.5 ÷ 10.7639 ≈ 17.42 sq m
- Square yards: 187.5 ÷ 9 ≈ 20.83 sq yd
- Acres: 187.5 ÷ 43,560 ≈ 0.0043 acres
Ordering tip: with 10% waste, plan for about 206.25 sq ft (round up to the nearest box size).

Example 2: patio with mixed shapes

Rectangle: 18 ft by 12 ft → 18 × 12 = 216.00 sq ft
Triangle bump-out: base 8 ft, height 6 ft → 0.5 × 8 × 6 = 24.00 sq ft
Circular planter: radius 2.5 ft → π × 2.5² ≈ 19.63 sq ft
Total patio area = 216.00 + 24.00 + 19.63 ≈ 259.63 sq ft
Conversions:
- Square meters: 259.63 ÷ 10.7639 ≈ 24.12 sq m
- Square yards: 259.63 ÷ 9 ≈ 28.85 sq yd
- Acres: 259.63 ÷ 43,560 ≈ 0.0060 acres

Frequently asked questions

Can I enter inches?
Yes. Enter feet and inches separately, or convert inches to feet (inches ÷ 12). For example, 8 inches = 0.667 feet.
What if I have a diameter instead of a radius?
Divide the diameter by 2 to get the radius. Then use circle area = π × r². For semicircles or quarter circles, multiply by 0.5 or 0.25.
How accurate are the results?
Accuracy depends on your measurements. The calculator uses standard formulas, π ≈ 3.14159, and industry-standard unit conversions. Expect small rounding differences.
Should I include closets, hallways, or stairs?
For flooring and cleaning, usually yes. For real estate listings or appraisals, local rules vary on what counts as square footage. When in doubt, check local guidance.
How much extra material should I buy?
It depends on the product and layout. A common rule of thumb is 5-15% waste. Confirm recommendations with your supplier or installer.
Can I use this for wall painting?
Yes, but compute wall area as height × (sum of wall lengths), and subtract doors and windows. The floor’s square footage is not the same as wall area.

Summary

The Square Footage Calculator turns real-world measurements into clear area totals for planning, budgeting, and ordering materials. Enter rectangles, triangles, and circles, then see per-shape results and totals in square feet, square meters, square yards, and acres. Use the calculator above with your measurements to plan your next flooring, painting, or landscaping project more confidently.

Disclaimer

This calculator provides general estimates for planning purposes and is not professional advice. Measurement standards and rules vary by region and purpose (construction, appraisal, permitting). Always verify requirements with your local authority, supplier, or licensed professional.