Rectangle Diagonal Calculator

Enter length and width to get diagonal, perimeter, area, ratio, and rounding options quickly here. Download CSV or PDF, share, and double-check work easily.

Calculator Inputs

Use positive numbers only.
Works with decimals and whole values.
Choose the same unit for length and width.
Control result display precision.
Apply rounding to computed values.
Get an extra converted summary section.
Reset

Example Data Table

Length Width Unit Diagonal Perimeter Area Angle (deg) Ratio
34cm5141253.13013:4
1010m14.142140100451:1
8.511in13.90143993.552.431417:22
Values shown with typical rounding for readability.

Formula Used

  • Diagonal: d = √(L² + W²)
  • Perimeter: P = 2(L + W)
  • Area: A = L × W
  • Diagonal angle: θ = arctan(W/L) (in degrees)
  • Unit conversion: convert through meters using fixed factors
These follow the Pythagorean theorem and basic rectangle properties.

How to Use This Calculator

  1. Enter the rectangle length and width.
  2. Select the unit that matches both inputs.
  3. Choose decimals and an optional rounding mode.
  4. Enable step-by-step if you want the workings shown.
  5. Click Calculate; the result appears above the form.
  6. Use Download CSV or Download PDF for exporting.
Tip: Keep inputs in the same unit for a clean ratio.

FAQs

1) What is a rectangle’s diagonal?

It is the straight line joining opposite corners. It forms a right triangle with the length and width, so the diagonal comes from the Pythagorean theorem.

2) Can I use decimals or fractions?

Yes. Enter decimals directly (like 2.75). If you have a fraction, convert it to a decimal first, then choose your preferred rounding and decimals for display.

3) Why does the ratio sometimes look unusual?

Aspect ratio is simplified using scaled integers, which can reflect rounding. Increase decimals or use cleaner inputs to get a more recognizable simplified ratio.

4) Does unit choice change the diagonal?

No, the shape is the same. The diagonal value changes only by unit scale. Use the conversion option to view results in another unit instantly.

5) What does diagonal angle mean?

It is the angle between the diagonal and the length side. It helps in layout, cutting, and design tasks where orientation matters.

6) Are the CSV and PDF exports exact?

Exports include the same rounded values shown on the page. If you need higher precision, increase the decimals before downloading.

7) What if my result is not showing?

Check that both numbers are positive and valid. If you refreshed after calculating, run the calculation again so the latest result is saved for export.

Made for quick geometry checks and classroom practice.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.