Square Footage Calculator

The square footage calculator totals area across any number of rooms or shapes, in a single combined figure, converting between imperial and metric units and pricing the result against a per-unit cost. Each room is independent, so shapes, units, and quantities can mix freely within one calculation.

• Shape. Twelve options cover Rectangle, Square, Circle, Oval or Ellipse, Triangle, Trapezoid, Rectangle Border, Circle Border, Annulus, L-Shape, Irregular Polygon, and Direct Area for a value already measured elsewhere.
• Dimensions and units. Fractions such as 3/8 and decimals are both accepted. Each dimension carries its own unit, from microinches through kilometers, so a single room can combine feet and inches without a manual conversion.
• Irregular Polygon. The boundary enters as x,y coordinate pairs, one per line, walking the perimeter in order; the shoelace formula finds the enclosed area for any convex or concave outline, which covers survey data or an irregular lot boundary that no standard shape fits.
• Quantity. Multiplies a room's area before it joins the total, for repeat identical spaces such as four matching panels or three identical tiles.
• Cost. Optional; a currency, a cost per unit area, and a pricing area unit multiply against the combined area for a project total.

Results report as a per-room breakdown alongside the combined total, across square feet, square inches, square yards, square meters, square centimeters, square millimeters, square kilometers, square miles, square micrometers, square microns, square microinches, acres, and hectares.

A rectangle border 10 feet by 8 feet with a 1 foot border has an area of (10 plus 2) times (8 plus 2), minus 10 times 8, which is 120 minus 80, or 40 square feet: the area of the border ring alone, without the inner rectangle it surrounds.

Each shape uses standard geometric formulas. All inputs are converted to meters first, calculated in square meters, and then converted to every supported area unit.

• Rectangle and Square: Area = Length × Width (Square uses Side × Side)
• Circle: Area = π × (Diameter ÷ 2)²
• Oval or Ellipse: Area = π × (Major ÷ 2) × (Minor ÷ 2)
• Annulus: Area = π × ((Outer ÷ 2)² − (Inner ÷ 2)²)
• Rectangle Border: Area = (L + 2B)(W + 2B) − LW
• Triangle (Heron): Area = √[ s × (s − a) × (s − b) × (s − c) ], where s = (a + b + c) ÷ 2
• Trapezoid: Area = ((Base1 + Base2) ÷ 2) × Height
• L-Shape: Area = (Overall L × Overall W) − (Cutout L × Cutout W)
• Irregular Polygon (Shoelace): Area = ½ |Σ (xᵢ · yᵢ₊₁ − xᵢ₊₁ · yᵢ)|

Accurate area numbers drive material budgets, schedules, and quotes across trades, design tasks, and planning workflows. A multi-room layout assembles whole-project totals without juggling several single-shape tools.

Building footprints, walls, ceilings, and roof sections size precisely from combined rectangle, L-Shape, and Trapezoid sections, without rounding a real floor plan down to one simple shape. Takeoffs assembled this way reduce overbuying, schedule crews against accurate coverage numbers, and present clear breakdowns to clients across multiple rooms or zones in a single estimate.

Carpet, tile, laminate, hardwood, and vinyl plank areas size room by room, with borders for thresholds and stair nosing included and totals converted to square meters or square yards for international quotes. The quantity field covers repeat installations across identical units, and the pricing area unit adjusts to compare suppliers that quote in different conventions.

Patios, walkways, lawns, mulch beds, and decorative rings size from the Circle, Oval, Annulus, and Irregular Polygon shapes, with pavers, sod, gravel, edging, and topsoil estimated for plots measured in acres or hectares. An irregular lot boundary from survey data enters as x and y coordinate pairs, with the shoelace formula computing the enclosed area.

Wall and fence coverage, including triangular gables and trapezoidal sections, sizes with each surface entered as its own room, for primer, paint, sealant, or stain quantities across one or more coats. Unit costs adjust to compare premium and standard product options side by side without re-entering any measurement.

Room sizes for listings, appraisals, and inspections check against floor plans, with irregular lot boundaries captured and clear area breakdowns presented to buyers, tenants, and contractors. Numbers convert between imperial and metric units to match the conventions used in each market or jurisdiction.