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Rectangle Calculator

Rectangle area, perimeter, and diagonal. A square is the case length = width.

Rated 4.7 out of 5 based on 340 reviews

Results

How to use Rectangle Calculator

  1. Enter length, width. Leave a field blank only when the page says the value is missing.
  2. Read the result rows under the form. Errors appear in the status line. Nothing is uploaded.
  3. Rounding follows IEEE floating point in this browser unless the page says it uses integers or BigInt.

Rectangle Calculator

Area

ComputesRectangle area, perimeter, and diagonal. A square is the case length = width.
IncludesArea
IncludesPerimeter
IncludesDiagonal
Enginegeometry
UploadNone
AdviceArithmetic only

What Rectangle Calculator is

Area = lw. Perimeter = 2(l+w). Diagonal = √(l²+w²).

The formula runs in this tab. CZNull does not receive the numbers.

How this page computes

The diagonal is Pythagoras; see Pythagorean. A 3D box is not this page.

Entities and related jobs

Rectangle area, perimeter, and diagonal. A square is the case length = width. Named features: Area, Perimeter, Diagonal.

See also Pythagorean Theorem Calculator, Triangle Calculator, Circle Calculator.

Use cases

Rooms, screens, and sheet goods. This page assumes right angles. Paint coverage and 3D boxes are not computed here.

Limits

Invalid input appears in the status line. IEEE floating point applies unless a row says otherwise. CZNull does not receive the numbers.

Rectangle Calculator questions

Does this page upload my numbers?
No. The formula runs in the page you opened. CZNull does not receive the values.
What does Rectangle Calculator compute?
Area = lw.
Why is this its own URL?
Search queries name this job. Nearby modes stay on their own pages so inputs do not mix. Related calculators are linked below Rectangle Calculator.
8 by 3?
Area 24, perimeter 22, diagonal √73.
3D box?
No.
Can I treat the result as official?
No. Rounding and real-world rules can differ. Use the page to check the arithmetic.