📐Square Footage Calculator

Our square footage calculator gives you an instant, accurate area measurement for any room shape. Whether you need to calculate square footage for a flooring quote, a real estate listing, a paint estimate, or a tile order, understanding how floor area works will save you time and money on every project.

Square Footage Calculator for a Room by Length and Width

The most common use case is a standard rectangular room. Measuring square footage from length and width is straightforward: multiply the two room dimensions together. A room that is 15 feet long and 12 feet wide has an area of 180 square feet. This single calculation drives the material quantities for almost every flooring and painting project.

For accurate results, measure each wall at floor level and take the measurement from corner to corner. Walls in older homes are rarely perfectly straight, so take two measurements for each dimension and use the longer one to ensure you do not underorder material. Always measure in feet and convert any inches to a decimal fraction before multiplying: 6 inches is 0.5 feet, 9 inches is 0.75 feet, and 3 inches is 0.25 feet.

If your room has a closet or an alcove, measure that section separately as its own rectangle and add it to the main room total. Most rooms can be broken down into two or three rectangles whose individual areas, when summed, give the correct total square footage.

How to Measure the Square Footage of a House

Calculating home square footage involves measuring every finished, heated room and summing the individual areas. Real estate professionals in the United States follow the ANSI Z765 standard, which counts only above-grade finished living space. Garages, unfinished basements, and open porches do not count toward the official home square footage figure published in listings.

To measure a full house yourself, sketch a rough floor plan on paper and walk through each room with a measuring tape. Record length and width for every space including hallways, closets, and bathrooms. Calculate the area of each space individually, then add everything together. For rooms with irregular shapes, divide them into rectangles first.

A finished basement is typically listed separately from the above-grade living area in real estate disclosures. When comparing home values on a per-square-foot basis, confirm whether a listing's figure includes the basement to make a fair comparison between properties.

Square Feet Calculator for Flooring and Real Estate

Flooring projects require precise square footage because flooring materials are sold in fixed units: boxes of hardwood planks, rolls of carpet, cases of tile. Knowing your exact floor area lets you calculate how many units to buy and how much waste allowance to add.

• Hardwood and laminate flooring: Add 10 to 15 percent for waste from end cuts and the staggered layout pattern.
• Ceramic and porcelain tile: Add 10 percent for straight-set layouts and 15 percent for diagonal layouts, which produce more cut waste at the room perimeter.
• Carpet: Carpet is sold in 12-foot-wide rolls, so room dimensions relative to roll width affect the amount needed. Add 10 percent to account for seams and pattern matching.
• Luxury vinyl plank (LVP): Add 10 percent for standard layouts.

In real estate, home value is frequently expressed as a price per square foot. Dividing the sale price by the total square footage gives you a number you can compare across similar properties in the same neighborhood. A home selling for $400,000 with 2,000 square feet of living space is priced at $200 per square foot. Understanding this ratio helps buyers and sellers assess whether a listing is priced fairly relative to comparable homes.

Calculating Area for Non-Rectangular Spaces

Not every space is a simple rectangle. This calculator handles triangles, circles, L-shapes, and trapezoids using the correct geometric formula for each shape.

An L-shaped room is the most common irregular floor plan. The simplest approach is to calculate the area of the full bounding rectangle (the largest rectangle that would fully contain the L-shape), then subtract the area of the missing corner cutout. A room that is 20 feet wide and 15 feet deep overall, with an 8 by 8 foot corner removed, has a total floor area of 300 minus 64 equals 236 square feet.

Circular areas appear in garden beds, round patios, and decorative features. The formula is pi multiplied by the radius squared, where the radius is half the diameter. A circular garden bed 10 feet across has a radius of 5 feet and an area of roughly 78.5 square feet. This figure tells you how much mulch, sod, or ground cover to order for that space.

Converting square footage to square meters is straightforward: multiply square feet by 0.0929. One square meter equals approximately 10.76 square feet. This conversion matters when working with imported tile, European flooring products, or international real estate comparisons.