Remember, the input can only be in feet (ft), inches (in), yards (yd), centimetres (cm), millimetres (mm) and metres (m) but never a combination of two different units! Also, we are assuming that the width of the border is even along the length and width of the rectangle.

Inner area = (Length x Width)Total area = (Length + (2 x Width of border)) x (Width + (2 x Width of border))Area of a Rectangle border = Total area – Inner areaLength (drop down ft, in, yd, cm, mm, m)Width (drop down ft, in, yd, cm, mm, m)Border width (drop down ft, in, yd, cm, mm, m)

Price per unit (drop down ft2, in2, yd2, cm2, mm2, m2)

To understand how to calculate square footage we must first begin with the definition of area. An area is the size of a two-dimensional surface. The area of a rectangle is the space contained within a set of lines. To find out the area of a rectangle border, we need to subtract the area of the inner rectangle from the area of the outer rectangle. These lines should be measured in feet (ft) for square footage calculations and if needed, converted to inches (in), yards (yd), centimetres (cm), millimetres (mm) and metres (m).

**The formula:**Inner area = (Length x Width)Total area = (Length + (2 x Width of border)) x (Width + (2 x Width of border))Area of a Rectangle border = Total area – Inner area

**Answer** = (Side length x Side length) square area

**Abbreviations of unit area: ** ft2, in2, yd2, cm2, mm2, m2

**Where do you need it in daily life?**

Our Square Footage Calculator helps you calculate the area required for ceiling mouldings, drop ceilings, roofing shingles, landscaping for a garden, tiling and flooring borders.

**What measurements do you need?**

You need to know the length and the width of the inner rectangle along with the width of the border in either feet (ft), inches (in), yards (yd), centimetres (cm), millimetres (mm) or metres (m).

**What can you calculate with this tool?**

You can calculate the area of the rectangular border in square feet, in square inches, square yards, square centimetres, square millimetres and square meters. Yes, our tool is that awesome.

Our calculator gives you the option of calculating the exact cost of materials. All you have to do is enter the price per unit area and voila, you have the total cost of materials in a single click!

**Conversion factors:**

To convert among square feet, square inches, square yards, square centimetres, square millimetres and square meters you can utilize the following conversion table.

Square feet to square yards | multiply ft2 by 0.11111 to get yd2 |

Square feet to square meters | multiply ft2 by 0.092903 to get m2 |

Square yards to square feet | multiply yd2 by 9 to get ft2 |

Square yards to square meters | multiply yd2 by 0.836127 to get m2 |

Square meters to square feet | multiply m2 by 10.7639 to get ft2 |

Square meters to square yards | multiply m2 by 1.19599 to get yd2 |

Square meters to square millimetres | multiply the m2 value by 1000000 to get mm2 |

Square meters to square centimetres | multiply the m2 value by 10 000 to get cm2 |

Square centimetres to square metres | multiply the cm2 value by 0.0001 to get mm2 |

Square centimetres to square millimetres | multiply the cm2 value by 100 to get mm2 |

Square millimetres to square centimetres | multiply the mm2 value by 0.000001 to get cm2 |

Square millimetres to square metres | multiply the mm2 value by 1000000 to get m2 |