Calculate the Grade Slope, Roof Pitch, Angle and Length of Rafter using this roof pitch calculator. A useful and handy tool for civil engineer and construction workers.

The ratio of the rise to run (horizontal span) of the roof is known as Roof pitch. It is also known as inclination angle.

It is necessary to determine the roof pitch and slope of your new roof. This will help you in finding how much water/snow falls off the roof and type of roofing materials.

When planning for expansion and installing skylights knowing the pitch of your roof is helpful.

**How to use Roof Pitch Calculator?**

Steps to use roof pitch calculator are given below:

- To start, measure length of run (half of roof span) using measure tape.
- Then, measure the rise of roof. Please follow above given figure for better understanding.
- Enter the details in above calculator and result will be shown.

**How to Calculate Roof Pitch Manually?**

You can calculate roof pitch, grade slope, rafter length and declination angle by yourself If you do not want to depend on this roof pitch calculator. The formulas to calculate roof pitch, grade slope, rafter length and declination angle have been mentioned below with examples.

For all the examples we will consider the rise = 10 ft and run = 20 ft respectively.

**Roof Pitch Formula :**

Pitch = rise/(run/12)

Pitch = 10/(20/12)

Pitch = 6/12

**Slope Formula :**

Grade Slope = (rise/run) x 100

slope = (10/20) x 100

slope = 50%

**Angle Formula :**

Angle = atan(rise/run)

Angle = atan(10/20)

Angle = 26.5650 Deg

**Rafter Length Formula :**

(Rafter)^{2} = (Rise)^{2} + (Run)^{2}

(Rafter)^{2 }= (10)^{2 }+ (20)^{2}

Rafter = 22.36 ft

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