The roofing calculator estimates the area of a new roof and the cost required to install it. The tool also estimates the roofing material to construct a new roof, as per the US standards. It includes the shingle bundles, squares of roofing material, and rolls of felt.

Our roof calculator can be helpful in many ways while considering a roofing project:

- It can help calculate cost differences among multiple roofing options
- Get an estimate of the roofing project cost before initiating
- Choosing an affordable material type for new roofing, etc.

**> Step 01:** Calculate the area of the house by using the formula “**Length х Width**”

**> Step 02: **Calculate the pitch of the roof

**> Step 03: **Convert the roof pitch to the corresponding angle by using the formulas:

\(Pitch\left(%\right) = \dfrac{x}{12} х 100%\)

\(Pitch\left(deg\right) = arctan[Pitch\left(%\right)]\)

**> Step 04: **Use the formula below to calculate the roof area.

\(\text{Roof Area} = \dfrac{\text{Base Area}}{cos[Pitch\left(deg\right)]}\)

**Data Given:**

- Length of the house = 20 feet
- Width of the house = 15 feet
- Roof pitch = 6/12

Base area = Length × Width

Base area = 20 feet × 15 feet

Base area = 300 square feet

Pitch (%) = (6/12) × 100%

Pitch (%) = 50%

Pitch (deg) = arctan(50%)

Pitch (deg) = 26.57 degrees

Roof area = Base area / cos(Pitch (deg))

Roof area = 300 square feet / cos(26.57 degrees)

Roof area = 333.18 square feet

Therefore, the roof area for the given house is approximately 333.18 square feet. Here, entering the data given in the roof calculator provides area measurements in different units rather than just square feet.

When the shape of the roof is complicated as shown in the following figure, the roof area calculations do not remain simple. Even simple equations are not considerable in the situation.

In this situation, you can divide the whole roof into simple and smaller sections. Now the next step is to calculate areas for these small sections. At last, adding up all the areas together gives a more accurate estimation of the roof area, even when using the roofing calculator above.

- As complex shapes can be prone to human measurement errors, dividing the roof into smaller parts ensures the removal of these errors.
- No matter whether your roof has multiple slopes, gables, dormers, or other features, the approach provides flexibility in estimating roofing area.
- Breaking down complex areas into smaller areas introduces ease of calculation.

Roof pitch gives you an idea of a rise in inches for every 12 inches run. It does not directly affect the roofing area, as it is based on the dimensions of the house (Length х Width). However, the roof pitch impacts the roofing material requirements.

For example; the steeper the roof is, the more surface area it covers, which needs more material to cover it. Conversely, a flatter roof will have a smaller surface area and therefore require less material.

In the United States of America, the concept of roof pitch is used. Whereas in other parts of the world, the roof angle is considered as a deciding factor for the roofing material needs.

Pitch | Angle | Multiplier |
---|---|---|

1/12 | 4.8° | 1.003 |

2/12 | 9.5° | 1.014 |

3/12 | 14.0° | 1.031 |

4/12 | 18.4° | 1.054 |

5/12 | 22.6° | 1.083 |

6/12 | 26.6° | 1.118 |

7/12 | 30.3° | 1.158 |

8/12 | 33.7° | 1.202 |

9/12 | 36.9° | 1.25 |

10/12 | 39.8° | 1.302 |

11/12 | 42.5° | 1.357 |

12/12 | 45.0° | 1.414 |

13/12 | 47.3° | 1.474 |

14/12 | 49.4° | 1.537 |

15/12 | 51.3° | 1.601 |

16/12 | 53.1° | 1.667 |

17/12 | 54.8° | 1.734 |

18/12 | 56.3° | 1.803 |

19/12 | 57.7° | 1.873 |

20/12 | 59.0° | 1.944 |

21/12 | 60.3° | 2.016 |

22/12 | 61.4° | 2.088 |

23/12 | 62.4° | 2.162 |

24/12 | 63.4° | 2.236 |

You should replace your house roof every 20 years.

Following are the considerable signs of a damaged roof:

- Missing Shingles
- Broken, Cracked, or Curling Shingles
- Hail Damage
- Leaky gutters
- Water Damage on Walls or Ceilings
- Problems in the Attic, etc.

**Family Handyman:** Signs of a Damaged Roof

**Forbes:** Roofing Types You Need to Consider