Square Footage & Room Area Calculator
Add up rooms and plots of any shape in sq ft, m², gaj or acres.
Rooms and areas
Cost optional
Breakdown
| Item | Shape | Each | × | Area |
|---|
About the Square Footage & Room Area Calculator
Work out the area of a room, a whole floor or a plot of land. Add each part as a rectangle, an L-shape, a triangle (from its base and height or from its three sides), a circle or semicircle, a trapezoid, a four-sided plot measured by its sides and one diagonal, a regular polygon or a list of corner coordinates. Sizes can be typed in metres or in feet and inches, items can be repeated or subtracted, and the total is shown in square feet, square metres, square yards (gaj), acres, hectares, cents and gunthas — with a cost at your rate.
Each item is drawn as you type, so you can see that the shape matches what you measured.
How to use it
- Pick Metric or US for the default units — you can still type any length with its unit, such as
12' 6"or3.8 m. - For each room or part of the plot, choose the shape and enter its sizes. Use How many for identical rooms and tick Subtract for a courtyard, a stair opening or another part to take away.
- For an irregular plot, measure all four sides and one diagonal and use Four sides + diagonal, or split it into triangles; with a survey sketch or site plan, type the corner coordinates in order.
- Read the total in the unit you need, add a rate per sq ft, m², sq yd or acre for the cost, and copy or download the list.
Examples
14 m² = 150.69 sq ft = 16.74 sq yd (gaj)
6 × 5 − 2 × 2 = 26 m² = 279.86 sq ft
2 × 168 − 9 = 327 sq ft = 30.38 m²
Two triangles of 600 m² each (Heron) = 1,200 m² = 0.2965 acres = 29.65 cents = 11.86 gunthas
Shoelace formula: 400 m² = 4,305.56 sq ft
Formulas
- Rectangle: length × width. L-shape: overall length × overall width − the missing corner.
- Triangle: base × height ÷ 2, or from three sides by Heron’s formula √(s(s − a)(s − b)(s − c)) with s = half the perimeter.
- Circle: π × diameter² ÷ 4; a semicircle is half of that.
- Trapezoid: (side 1 + side 2) ÷ 2 × the height between them.
- Four sides + diagonal: the diagonal splits the plot into two triangles whose areas come from their three sides — the usual way to measure a plot with a tape. The two triangles are taken to be on opposite sides of the diagonal.
- Regular polygon: n × side² ÷ (4 × tan(180° ÷ n)).
- Corner coordinates: the shoelace formula ½ |Σ (xᵢ yᵢ₊₁ − xᵢ₊₁ yᵢ)| for the corners in order.
Units
1 ft = 0.3048 m exactly, so 1 sq ft = 0.09290304 m² and 1 m² = 10.7639 sq ft. A gaj is a square yard (9 sq ft = 0.83612736 m²); an acre is 43,560 sq ft (4,046.86 m²); a cent (used in Kerala and Tamil Nadu) is 1/100 acre = 435.6 sq ft; a guntha (used in Maharashtra, Karnataka and Telangana) is 1/40 acre = 1,089 sq ft; a hectare is 10,000 m². Units such as the bigha, which differ from state to state, are not used.
Measuring tips
Measure each wall at floor level and in two places — rooms are rarely perfect rectangles. For an irregular room, split it into rectangles and triangles. For property, check whether a figure is carpet, built-up or super built-up area: they are measured differently, and this calculator gives the area of exactly what you enter.
Limitations
- Corner coordinates are treated as points on a flat plane; for large tracts measured as latitude and longitude use a surveyor’s area, not this tool.
- Curved walls other than circles and semicircles need to be split into straight pieces.
- "Four sides + diagonal" assumes the plot does not fold back on itself; very irregular plots need more measurements.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
How do I calculate the square footage of a room?
Multiply the length by the width in feet. A 12 ft × 14 ft room is 168 sq ft. With feet and inches, type them as they are — 12' 6" is 12.5 ft — and the calculator converts them.
How do I find the area of an L-shaped room?
Measure the overall length and width as if the room were a full rectangle, then the length and width of the missing corner, and choose L-shape. Or add the room as two rectangles.
How many square feet are in one gaj?
Nine. A gaj is a square yard, and a yard is 3 feet, so 1 gaj = 3 × 3 = 9 sq ft, and a 100-gaj plot is 900 sq ft.
How do I measure an irregular plot?
Measure the four sides and one diagonal (corner to opposite corner) and use Four sides + diagonal. For plots with more corners, split them into triangles along diagonals, or enter the corner coordinates from a site plan.
How many square metres is 1,000 sq ft?
1,000 × 0.09290304 = 92.90 m².