Project estimates

Square Footage Calculator

Enter length and width in feet to calculate rectangular area in square feet, square meters, square yards, and acres.

Last reviewed May 17, 2026 by ToolSpilo Editorial Team.

Review method: Area formula, conversion outputs, and irregular-room guidance reviewed against current unit-conversion references.

Calculator tool

How this calculator works

Use the explanation to understand the formula, assumptions, and practical limits behind the calculator result.

What Does the Square Footage Calculator Do?

This calculator finds the area of a rectangular space from length and width. It is useful before flooring, tile, paint, roofing, or other home-project calculations that depend on a reliable area estimate.

Formula Used

Square footage=Length×Width\text{Square footage} = \text{Length} \times \text{Width}

The calculator also converts the same area into square meters, square yards, and acres.

Worked Example

For a room that is 20 ft long and 15 ft wide:

20×15=300 sq ft20 \times 15 = 300\text{ sq ft}

That is about 27.87 m², 33.33 sq yd, or 0.00689 acres.

How to Handle Irregular Rooms

For an L-shaped or irregular space, split the floor into simple rectangles, calculate each rectangle separately, then add the results together. That is usually clearer and more accurate than guessing one large rectangle around the whole outline.

How Should You Use the Result?

Area is often the starting point, not the final purchase amount. Tile, paint, roofing, and concrete projects usually need their own waste factors, coverage rates, or depth assumptions after the square footage is known.

Frequently asked questions

Can I use this for an L-shaped room?

Yes, but not in one step. Divide the shape into rectangles, calculate each rectangle's area, and add them together. That keeps the geometry simple and makes the result easier to verify.

Why is square footage different from linear feet?

Linear feet measure length only. Square feet measure area, so both length and width matter. A 20-foot wall and a 20-square-foot floor are completely different quantities.

Should I round before using the area in another calculator?

Keep the more precise result until the final step when possible. Early rounding can create avoidable drift once the area is multiplied by coats, waste, depth, or material coverage.

Why does a material calculator still need extra inputs after square footage?

Because area alone does not tell you everything. Paint also needs coats and coverage, tile needs tile size and waste, and roofing needs pitch and product coverage.