Enter Dimensions
Examples: 10.5, 3, 0 is allowed. Negative numbers are not.
Formula
Result
Enter dimensions to calculate the area.
What is a Rectangle?
A rectangle is a four-sided shape (a quadrilateral) with four right angles (90°). A key property is that its opposite sides are equal in length and parallel to each other. A square is a special type of rectangle where all four sides are equal.
What is Area?
Area is the measure of the two-dimensional space a shape occupies. It's quantified in "square units" (like square meters or square feet). For a rectangle, you can think of the area as the total number of 1x1 unit squares that can fit inside it. The calculator above finds this value by multiplying the length and width.
Calculate from Diagonal and One Side
If you know the length of a rectangle's diagonal and one of its sides, you can find the area. The diagonal and two adjacent sides form a right-angled triangle. Using the Pythagorean theorem (a² + b² = c²), you can find the length of the missing side and then calculate the area.
Home & DIY Projects
Calculating area is essential for home improvement. Whether you're buying flooring, painting a wall, or tiling a bathroom, you need to know the area to purchase the correct amount of material. This avoids waste and ensures you don't run out mid-project. For a wall that is 8 ft high and 12 ft long, you would need enough paint to cover 96 ft².
Real Estate
In real estate, property size is almost always listed in square feet or square meters. This "square footage" is a primary factor in determining a property's value. It's calculated by measuring the length and width of each room and summing the areas. This gives buyers a standardized way to compare the size of different homes.
Gardening & Landscaping
When planning a garden, knowing the area of a rectangular plot helps determine how many seeds or plants you can fit. It's also crucial for calculating the amount of fertilizer, soil, or mulch needed to cover the area. For example, if a bag of fertilizer covers 50 m², you can figure out exactly how many bags to buy for your 20 m² garden bed.