Square Footage Calculator
Calculate area for rooms, floors, and land
How to use this calculator
Calculating square footage is straightforward with our tool. Follow these simple steps to get accurate area measurements for any space:
- Select your shape: Choose from rectangle, circle, triangle, or trapezoid depending on the area you need to measure.
- Enter your dimensions: Input the length, width, radius, or other measurements as required. You can select different units for each measurement.
- Click calculate: Press the calculate button to instantly see your results in multiple units including square feet, square meters, square yards, and acres.
- For irregular rooms: Break the space into smaller regular shapes, calculate each separately, and add the results together.
The calculator automatically converts between units, so you can measure in feet but view results in meters if needed for international projects or material ordering.
Understanding square footage measurements
Square footage is the most common area measurement used in the United States for real estate, construction, and home improvement projects. Understanding how to calculate and use square footage is essential for homeowners, contractors, and anyone involved in property transactions.
Why square footage matters
Accurate square footage calculations affect many aspects of homeownership and construction. Real estate prices are often quoted per square foot, making it crucial for comparing property values. Insurance premiums, property taxes, and heating and cooling costs all depend on the size of your space. When planning renovations, knowing your square footage helps you estimate material costs and labor requirements.
Measuring different spaces
Rooms rarely have perfectly simple shapes. Most homes contain a mix of rectangular rooms, closets, bay windows, and odd angles. The key to accurate measurement is breaking complex spaces into simpler geometric shapes. A room with a bay window, for instance, can be measured as a main rectangle plus a triangle or trapezoid for the window alcove.
Common measurement mistakes
One frequent error is confusing linear feet with square feet. Linear feet measure length only, while square feet measure area. A 100 linear foot roll of flooring is not the same as 100 square feet of coverage. Another common mistake is forgetting to account for closets, alcoves, or built-in features when measuring rooms. Always measure the total floor area, then subtract any areas that will not receive the treatment you are planning.
Gross versus net square footage
In real estate, you may encounter both gross and net square footage. Gross square footage includes all enclosed space measured from the exterior walls. Net square footage, also called livable or usable square footage, excludes walls, stairwells, and other non-usable areas. Most residential listings use gross square footage, while commercial properties often distinguish between the two.
Square footage examples
Example 1: Measuring a bedroom for carpet
Sarah needs to carpet her master bedroom, which measures 14 feet by 12 feet, plus a 3 foot by 4 foot closet alcove. The main room is 14 x 12 = 168 square feet. The alcove adds 3 x 4 = 12 square feet. Total area: 180 square feet. Adding 10% for waste, she should order at least 198 square feet of carpet. When purchasing, she rounds up to the next available roll size to ensure complete coverage.
Example 2: Calculating an L-shaped room
Tom needs to measure his L-shaped living and dining area for hardwood flooring. He divides the space into two rectangles: the main living area is 20 feet by 15 feet (300 square feet), and the dining nook extends 10 feet by 8 feet (80 square feet). Total area: 300 + 80 = 380 square feet. With a 10% waste allowance for the wood floor installation, Tom orders 418 square feet of hardwood planks.
Example 3: Whole house calculation
Maria wants to know the total square footage of her single-story home for insurance purposes. She measures each room: living room (18 x 14 = 252 sq ft), kitchen (12 x 10 = 120 sq ft), master bedroom (15 x 12 = 180 sq ft), second bedroom (12 x 10 = 120 sq ft), bathroom (8 x 6 = 48 sq ft), hallway (15 x 4 = 60 sq ft), and entry (6 x 5 = 30 sq ft). Total living space: 810 square feet. Her detached garage (20 x 22 = 440 sq ft) is listed separately since it is not heated living space.
Example 4: Pricing a home by square footage
A home is listed at $450,000 and measures 2,250 square feet. To find the price per square foot: $450,000 divided by 2,250 = $200 per square foot. A comparable home nearby sold for $380,000 at 2,000 square feet, which equals $190 per square foot. This comparison suggests the listed home may be slightly overpriced for the neighborhood, though factors like condition, upgrades, and lot size also affect value.
The calculation formulas
Rectangle or square: Area = Length x Width
Circle: Area = pi x radius squared (3.14159 x r x r)
Triangle: Area = 0.5 x Base x Height
Trapezoid: Area = 0.5 x (Side A + Side B) x Height
These formulas work with any unit of measurement, but ensure all measurements use the same unit before calculating. The result will be in square units of whatever you started with.
Frequently Asked Questions
How do I measure irregular rooms?
Irregular rooms can be measured by dividing them into smaller regular shapes. Start by identifying the largest rectangular portion of the room and measure that first. Then measure any alcoves, bay windows, closets, or bump-outs separately. Calculate the area of each section individually, then add all the areas together for the total square footage. For L-shaped rooms, imagine a line that would divide the space into two rectangles, measure each rectangle, and combine the results. This method works for any room shape, no matter how complex.
Should I include closets and hallways in square footage?
Yes, closets and hallways are typically included in the total square footage of a home. When measuring for real estate purposes, all finished and enclosed spaces count toward the total. This includes walk-in closets, reach-in closets, hallways, foyers, and entryways. However, for specific projects like flooring, you may want to measure these areas separately since they might require different materials or installation methods. Unfinished spaces like garages and unheated storage areas are usually counted separately from the main living area.
How do I calculate square footage from a floor plan?
When calculating square footage from a floor plan, check the scale provided on the drawing. Most architectural plans include a scale such as 1/4 inch equals 1 foot. Use a ruler to measure the dimensions on the plan, then multiply by the scale factor to get actual measurements. For example, if a room measures 3 inches long on a 1/4 inch scale plan, the actual length is 12 feet (3 divided by 0.25). Once you have the actual dimensions, multiply length by width for each room. Digital floor plans often include dimension labels, making calculations more straightforward.
What are average home sizes by type?
Home sizes vary considerably by type and location. Single-family homes in the United States average about 2,300 square feet, though this has increased from under 1,000 square feet in the 1950s. Apartments and condos typically range from 500 to 1,200 square feet, with studios averaging around 500 square feet and two-bedroom units around 900 square feet. Townhouses usually fall between 1,000 and 2,000 square feet. Tiny homes, a growing trend, are defined as under 400 square feet. McMansions, a term for oversized suburban homes, often exceed 3,000 square feet.
What is the difference between square feet and square meters?
Square feet and square meters are both units of area, but they belong to different measurement systems. Square feet are part of the imperial system used primarily in the United States, while square meters are part of the metric system used in most other countries. One square meter equals approximately 10.764 square feet, and one square foot equals approximately 0.0929 square meters. When comparing international property listings or working with imported materials, you may need to convert between these units. The metric system is also commonly used in scientific and engineering contexts.
What does price per square foot mean?
Price per square foot is a standardized way to compare real estate values across properties of different sizes. Calculate it by dividing the total price by the total square footage. For example, a 2,000 square foot home priced at $400,000 has a price per square foot of $200. This metric allows meaningful comparisons between a 1,500 square foot house and a 3,000 square foot house in the same area. However, price per square foot varies significantly by location, condition, features, and market conditions. Use it as one factor among many when evaluating property value.
How do I measure for flooring versus painting?
Flooring measurements focus on floor area only, while painting measurements require calculating wall area and often ceiling area. For flooring, measure the length and width of each room at floor level, accounting for any closets or alcoves you want to cover. For painting, measure the perimeter of each room and multiply by wall height to get total wall area, then subtract the area of windows and doors. Ceilings require the same floor area calculation. Paint coverage is measured in square feet per gallon, typically 350-400 square feet per gallon for one coat, so you can estimate how much paint to buy.
Does garage and basement square footage count?
Garages are almost never included in the living square footage of a home because they are not finished living space. Basements depend on whether they are finished and how they are accessed. A finished basement with direct interior access, normal ceiling height (at least 7 feet), and proper egress may be counted as living space in some markets, but many appraisers list it separately as "below-grade" square footage. Unfinished basements, root cellars, and crawl spaces are not counted. Different regions and real estate markets have varying standards, so check local conventions when comparing properties.
Measurement tips
Tools you will need
For accurate measurements, gather these essential tools: a 25-foot tape measure with a locking mechanism, a notepad and pencil for recording dimensions, a calculator or smartphone for quick math, and optionally a laser distance measurer for large spaces. Laser measurers can measure up to 100 feet instantly and are especially useful for high ceilings or long hallways where holding a tape measure is awkward.
Breaking spaces into rectangles
Most rooms, no matter how irregular, can be broken into a series of rectangles. Start by identifying the largest rectangular area and measure it first. Then measure any additional sections that extend beyond this main rectangle. For bay windows, bump-outs, alcoves, and closets, treat each as a separate rectangle. Draw a rough sketch as you measure, labeling each dimension. This approach prevents confusion and ensures you capture every part of the space.
Double-checking your work
Always measure twice to catch errors before they become expensive mistakes. After measuring length, measure again from the opposite end of the room to confirm. Check that opposing walls are the same length, as older homes often have rooms that are slightly out of square. If measurements differ by more than an inch, use the larger number for material ordering. Having a second person hold the tape can improve accuracy for longer measurements.
Adding waste allowance for materials
When ordering materials like flooring, tile, or carpet, always add a waste factor to your calculated square footage. Standard waste allowances are: 10% for simple rectangular rooms with straight-lay patterns, 15% for diagonal installations or rooms with multiple angles, and 20% for complex patterns or first-time installers. This extra material accounts for cutting waste, mistakes during installation, and future repairs. Keeping leftover materials in storage means you can repair damage without trying to match discontinued products years later.
Did you know?
- The average American home is 2,300 square feet, more than double the 1950s average of 983 square feet.
- New York City apartments average just 866 square feet, among the smallest in the United States.
- The world's largest building by floor space is the New Century Global Center in China at 18.9 million square feet.
- A regulation basketball court is exactly 4,700 square feet, making it a useful reference for visualizing area.
- The term "square footage" is primarily used in the United States, while most other countries use square meters.
Area formulas
- Rectangle: Area = Length x Width
- Circle: Area = pi x r squared
- Triangle: Area = 0.5 x Base x Height
- Trapezoid: Area = 0.5 x (a + b) x Height
Common conversions
- 1 square foot = 144 square inches
- 1 square yard = 9 square feet
- 1 square meter = 10.764 square feet
- 1 acre = 43,560 square feet