Perimeter Definition Our free online perimeter calculator allows you to quickly and easily calculate the perimeter of any square, rectangle, or rhombus. The tool also can take the height and width in one unit, such as inches, and output a different unit, such as meters. Also check out other similar calculators like the Square Footage Calculator. The Process The process is simple. 1. Type the height into the “Height” field. 2. Type the width into the “Width” field. 3. Select the unit used for the height and width measurements in the convenient Input Units drop-down box. 4. Select the unit you wish to use in the Output Units drop-down box. 5. Click “Calculate.” Your result will display on the screen. 6. Click “Back” to return to the initial screen for your next calculation. Important Notes Be sure to use the same measurement units in both the “Width” and “Height” fields. Don’t measure the width in feet and the height in centimeters For best results, measure as precisely as possible. Remember the old adage, “Garbage in, garbage out.” The calculator output is precise to two decimal points. This means that for best precision, you should use the smallest unit for output. For example, a width of 6.417 feet (6 feet 5 inches) and height of 8.417 feet (8 feet 5 inches) gives a perimeter that is rounded to 29.67 feet. If you multiply that out, it comes to 356.04 inches. If you change the output unit to inches, the calculation comes to 356.02 inches. The difference is small, but might have an impact on your finished result.

How to Calculate Perimeter Let's be honest - sometimes the best perimeter calculator is the one that is easy to use and doesn't require us to even know what the perimeter formula is in the first place! But if you want to know the exact formula for calculating perimeter then please check out the "Formula" box above.