Square Footage Calculator

How Many Square Feet Is a 15x20 Room?

A 15 × 20 ft room is 300 square feet — 27.87 square metres, or 33.33 square yards.

Multiply the two sides together: 15 × 20 = 300. In metric that is 4.57 m × 6.1 m = 27.87 m².

Scale drawing of a 15 by 20 ft room on a one-ft grid 15 ft 20 ft
A 15 × 20 ft room drawn to scale. Each grid square is one square foot.
Every unit you might be asked for.
UnitArea
sq ft300
27.87
sq yd33.33
sq in43,200
acres0.006887

What fits in a 15x20 room

Counted as a plain grid layout in whichever direction packs more in, with no walkways and no diagonal placement — so treat each figure as the floor, not the ceiling.

ItemFootprintHow many fitFloor used
King bed6.3 × 6.7 ft684%
Queen bed5 × 6.7 ft9100%
Full (double) bed4.5 × 6.3 ft984%
Twin bed3.2 × 6.3 ft1279%
Three-seat sofa3.2 × 7 ft1289%
Dining table (seats 6)3 × 6 ft1590%
Office desk2.5 × 5 ft24100%
Parking space9 × 18 ft154%
Compact car6 × 15 ft390%
Ping-pong table5 × 9 ft690%
8×10 area rug8 × 10 ft253%
Yoga mat2 × 5.7 ft2179%

How a 15 × 20 ft room lays out

At 1.3:1 this is the proportion most rooms are actually built to — long enough to give furniture a clear front and back, square enough that neither wall dominates the arrangement.

Two sofas 3 ft 2 in deep, facing each other across the 15 ft width, leave 8 ft 8 in between them — room for a coffee table and a walkway on both sides of it. The 20 ft wall takes a 7 ft three-seat sofa and still leaves 13 ft, so a second seating piece or a full run of storage fits on the same wall.

A footprint this size and shape is typically a studio apartment, a living room, or an open-plan living and dining room — typical ranges rather than a rule, and ballpark rather than sourced, like the figures above (see the methodology page).

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Materials for 300 square feet

Quantities include each material's usual waste allowance and round up to whole units, because you cannot buy part of a box.

MaterialSq ft to buyQuantity
Carpet330 (+10%)28 roll feet
Drywall330 (+10%)11 sheets
Flooring (laminate/vinyl)330 (+10%)17 boxes
Hardwood Flooring330 (+10%)15 boxes
Paint315 (+5%)1 gallon
Tile330 (+10%)22 boxes

Working with a 15x20 room

A 15 by 20 foot room is 300 square feet of floor, which is 27.87 square metres, 33.33 square yards, or 0.0069 of an acre. The arithmetic is a single multiplication — 15 × 20 — and every other figure on this page follows from it.

The walls are a different number. The perimeter of a 15 × 20 room is 70 feet, so with a standard 8 ft ceiling the four walls come to about 560 square feet before you deduct anything. Take off roughly 21 square feet for each door and 15 for each window: one door and two windows brings it to about 509 square feet, which at 375 square feet to the gallon is 2 gallons of paint per coat, or 4 for the two coats a colour change needs.

For flooring or tile, add the waste factor before you order rather than after. At the usual 10% allowance a 300 square foot floor needs 330 square feet of material bought, and a diagonal or herringbone lay pushes that to 345. The table above rounds each material up to whole boxes and sheets, because that is the smallest unit anyone will sell you.

If your room is not quite these dimensions, the calculator below gives the exact figure — or pick a shape from the calculator index if the room is not a plain rectangle. To add this room into a whole-house figure, use the multi-room calculator.

Measuring a different room

Change the numbers below and the live preview redraws this room to scale — or drag the drawing's handles to resize it. Switch to the drawing grid to sketch a room that is not a plain rectangle.

Live scale preview

The shape is drawn to scale and relabelled as you type.

Rectangle drawn to scale, 300 sq ft 15 ft20 ft 300 sq ft Grid: 1 square = 2 ft

An example to start from. Drag a handle or type a measurement and it becomes yours.

Frequently asked questions

How many square feet is a 15x20 room?

A 15 by 20 foot room is 300 square feet. Multiply the two sides together — 15 × 20 — and that is the floor area. The same figure is shown above in square metres, square yards and acres, along with a to-scale drawing and the quantity of each material a room this size needs.

What can fit in a room this size?

The table above counts how many of each item fit as a plain grid, laid whichever way round packs more in, with no walkways and no diagonal placement. Treat every figure as a floor rather than a ceiling: it tells you the room is physically large enough, not that the layout would be comfortable. A usable room generally needs 30 to 36 inches of clearance on at least one side of each piece of furniture.

Is this the floor area or the wall area?

The floor area. Wall area is a different calculation: multiply each wall's width by the ceiling height and add them together, then subtract the doors and windows. For a 15 by 20 room with an 8 ft ceiling, the four walls come to about (15 + 20) × 2 × 8 square feet before any deductions.

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