Rectangle Calculator
Calculate the area, perimeter, and diagonal of any rectangle from length and width. Free online rectangle properties calculator for construction, geometry, and design projects.
About This Calculator
The Rectangle Calculator computes three essential properties of any rectangle from just its length and width: area, perimeter, and diagonal. Simply enter the dimensions and get all three measurements instantly with a visual comparison chart.
The formulas used are:
- Area: A = l x w
- Perimeter: P = 2(l + w)
- Diagonal: d = sqrt(l^2 + w^2) (based on the Pythagorean theorem)
This all-in-one calculator is perfect for students, teachers, construction workers, architects, and DIY enthusiasts who need quick rectangle measurements for any project.
Common Uses
- Construction: Get area, perimeter, and diagonal for framing and layout
- Flooring: Calculate floor area and room diagonal for material estimates
- Design: Determine all rectangle dimensions for furniture or space planning
- Education: Verify geometry homework and understand rectangle properties
Frequently Asked Questions
How do you find the diagonal of a rectangle?
The diagonal is found using Pythagoras: d = sqrt(l^2 + w^2).
How do you calculate the area of a rectangle?
The area of a rectangle is calculated as A = l x w, where l is the length and w is the width.
What is the perimeter formula for a rectangle?
The perimeter of a rectangle is P = 2(l + w), where l is the length and w is the width.
What properties does this calculator compute?
This calculator computes three properties of any rectangle: area (l x w), perimeter (2(l + w)), and diagonal (sqrt(l^2 + w^2)).
Is this calculator free to use?
Yes, all calculators on Calculy are completely free to use with no registration required.
Can I share my calculation?
Yes, the URL saves your length and width inputs so you can bookmark or share the exact calculation.
What units should I use for length and width?
You can use any consistent unit (inches, feet, cm, meters). The area, perimeter, and diagonal will be in the same unit squared or linear units as your input.
Can I calculate area if I only know the diagonal?
The diagonal alone is not enough to find area. You need either length and width, or the diagonal plus one side to use the Pythagorean theorem to find the missing dimension.