Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Calculate area in square feet for a rectangle, L-shaped room, or circle.
This calculator finds the area of a space in square feet, supporting three real room shapes rather than assuming every space is a simple rectangle: a plain rectangle, an L-shaped room (two rectangular sections combined), and a circle.
Pick your shape. For a rectangle, enter length and width. For an L-shaped room, enter the main rectangle's length and width, plus a second section's length and width (measure the room as two overlapping rectangles that together cover the whole floor plan). For a circle, enter the radius (half the diameter).
Rectangle: Area = Length × Width
L-Shape: Area = (Length1 × Width1) + (Length2 × Width2)
Circle: Area = π × Radius²
The L-shape calculation treats the room as two separate rectangles whose areas add together -- the most common way to break down an irregular room into pieces you can actually measure with a tape.
Use this for flooring, carpet, or paint quantity estimates, real-estate listing area calculations, or any project priced or planned by square footage. For flooring specifically, the Flooring Calculator builds on this same area math with material-specific waste factors and box/carton counts.
The two-rectangle method can be done in more than one way, and each gives the same total if the room is measured properly. Imagine a hypothetical L-shaped room whose overall bounding box is 16 feet by 12 feet, with a 6 by 8 foot corner missing. The bounding box has 192 sqft, and removing the missing corner leaves 192 minus 48, which is 144 sqft. That matches splitting it into a 12 by 10 rectangle and a 6 by 4 nook as in the example above. If two methods disagree, recheck the measurements.
Decide up front whether closets, alcoves, hallways, and stairs count. For flooring, you usually include closets that will get the same floor. For paint, wall area is a different question, since paint depends on wall height and openings, not floor area. For real-estate or appraisal purposes, there may be a required standard for what counts as living area, so check with an appraiser or local rules.
For a circular patio or a round room, the tool needs the radius, which is half of the diameter. A hypothetical 10 foot diameter circle has a 5 foot radius and an area of about 78.5 sqft. For a half-round bay or alcove, calculate a full circle and halve it, then add that to the rest of the room as another section.
The floor area is the amount to cover, not the amount to purchase. Cutting, pattern matching, and mistakes require extra material, so flooring is commonly ordered with a margin above the measured area. Ask the manufacturer or installer for the right percentage for your layout.
Break it into rectangular sections you can measure separately (like the L-shape option here), calculate each section's area, and add them together -- this works for most real room layouts, even ones more complex than a simple L.
Measure the radius -- the distance from the center to the edge -- not the full diameter across. If you only have the diameter, divide it by 2 before entering it here.
Generally yes for interior room area, though real-estate listings sometimes follow specific regional measurement standards (like measuring to the exterior wall) that can differ slightly from a simple interior room calculation.
Split it into a rectangle and a triangle. The triangle area is half the base times the height. Add the two areas together.
Include it if it will receive the same flooring or if you want the total area. Keep it separate if you are pricing different materials.
Yes. Enter values like 10.5 for ten and a half feet. Convert inches to decimals by dividing by 12.