Loan Square Footage Calculator
Four shapes, not just rectangles — and a rooms list that keeps a running total for the whole project, in square feet and square meters, with a cost-per-foot figure when you need a budget.
Rooms / areas list
| Area | Sq ft | Sq m | |
|---|---|---|---|
| Nothing added yet — measure a shape above and tap "Add this area". | |||
List total: 0 sq ft.
How it works
Rectangle: length × width. Triangle: base × height ÷ 2 (the height is the perpendicular distance, not the slanted side). Circle: π × radius². Trapezoid: (A + B) ÷ 2 × height — average the two parallel sides, then multiply by the distance between them. Square meters convert at 1 sq ft = 0.0929 m². The list adds every shape in square feet regardless of the unit you measured in, so a mixed metric/imperial project still totals correctly.
Formula & worked example
Formula: Rectangle: length × width. Triangle: base × height ÷ 2. Circle: π × radius². Trapezoid: (top + bottom) ÷ 2 × height. Metric inputs are converted at 1 m² = 10.7639104 sq ft, and results are also shown in square metres (1 sq ft = 0.09290304 m²).
Worked example: A 12 ft × 10 ft room is 120 sq ft — 11.15 sq m. A circular pad with a 5 ft radius covers π × 25 = 78.54 sq ft.
When to use this
- Flooring, paint or tile shopping where everything is priced per square foot.
- An L-shaped or multi-room space a single length × width gets wrong.
- A landlord, listing or contractor's square-foot claim you want to verify.
- Comparing material quotes that use different per-sq-ft prices.
How to use it, step by step
- Pick the shape — rectangle for most rooms; add shapes for L-shaped spaces.
- Enter dimensions in feet/inches, metres or centimetres.
- Give the piece a name if you are building a list (e.g. 'Kitchen').
- Add a per-sq-ft material cost to turn area into budget.
- Repeat per room and read the running total.
What the inputs mean
| Input | What it is | Typical values |
|---|---|---|
| Length / width | The two sides of the space | Rooms commonly 8–20 ft |
| Radius | For circles: centre to edge | Round patios, rugs, pools |
| Cost per sq ft | Material price for the budget line | Flooring $2–$10; tile $5–$15 installed varies |
Another worked example
An L-shaped living space made of a 14 × 11 ft main area plus an 8 × 6 ft nook totals 154 + 48 = 202 sq ft. At $3.50 per sq ft for flooring material, that is $707.00 before waste — and the nook's 48 sq ft is exactly the part a single-rectangle estimate would have silently dropped.
Frequently asked questions
How do I measure an L-shaped or odd-shaped room?
Break it into rectangles (and triangles or trapezoids where needed), measure each piece, and use the "Add this area to the list" button for each — the list keeps the running project total for you.
How do I convert square feet to square meters?
Multiply square feet by 0.0929 (or divide by 10.764). This calculator always shows both, and you can enter measurements in meters and still get a square-foot total for US materials pricing.
What is the square footage of a 12×12 room?
144 square feet — length times width. A 12 ft × 10 ft room is 120 sq ft, and a circle with a 5 ft radius is about 78.5 sq ft. Try them above.
Does square footage include walls or closets?
For flooring and paint, measure the floor area of each space you will actually cover, closets included if they get the same material. Real-estate listings use different (often exterior-wall) conventions — this tool measures the area you give it.
🏗️ Pouring something on that area?
The Concrete Calculator turns dimensions into cubic yards, bag counts and a costed shopping list.
Should I subtract closets, islands and fixed cabinets?
For flooring, subtract only areas that truly will not be covered — and add waste back on top. For paint, subtract large openings. When in doubt, measure the full rectangle: over-buying one box beats reordering a discontinued line.
How do I measure an irregular room?
Split it into rectangles (and a triangle or two) on paper, measure each, and add them here one at a time with names. The list total is your room — surveyors do exactly this, just with lasers.