Calculator Servicescalculatorservices.com
Construction

Roof Pitch Calculator

Slope of a roof. Free online Roof Pitch Calculator. Calculate roof pitch online — fast, accurate, mobile-friendly, no signup needed.

Pitch = rise / run (expressed as x-in-12 or degrees).
Pitch (angle°)
26.565051

Derivation

  1. ├── 01Givenrise = 6, run = 12
  2. ├── 02Formula180 × atan(t / a) / π
  3. └── 03Compute Pitch (angle°)26.565051
Did you know?

US roof pitches are traditionally expressed as rise-in-12: a 6/12 roof rises 6 inches for every 12 horizontal.

§01What is

Understanding the Roof Pitch Calculator

The Roof Pitch Calculator computes Pitch (angle°) from 2 inputs: rise (in), run (in). Slope of a roof.

On a construction site, estimates that come in 10% off add up to six-figure overruns. Running the quantities with a calculator instead of a rule-of-thumb gets you closer to the truth with zero extra effort. The Roof Pitch Calculator sits in that toolkit — it slope of a roof. Enter your numbers above and the result updates instantly; every step of the math is shown in the Derivation panel so you can see exactly how the answer was reached.

§02The Formula

How it’s calculated

180 × atan(t / a) / π

Where

rise
Rise (in)
run
Run (in)
§03Practical Example

Step-by-step walkthrough

Scenario

Apply the formula to a realistic set of inputs: Rise (in) = 6, Run (in) = 12.

  1. 01Start by noting the input — Rise (in): 6.
  2. 02Start by noting the input — Run (in): 12.
  3. 03Substitute these values into the formula: 180 × atan(t / a) / π
  4. 04Compute Pitch (angle°): the calculator returns 26.5651.
  5. 05Cross-check the answer by opening the Derivation panel above — every line of math is shown so you can follow the computation end-to-end.
§04Variants

Common Roof Pitch Problems

The formula gets rearranged depending on which variable you need. Here are the patterns you’ll run into in the real world — find the one that matches your problem and follow the worked steps.

01 · PATTERN

Rise (in) halved

rise = 3 (from 6)

Keep every other input at its default and halve the rise (in). See how pitch (angle°) responds.

  1. 01New Rise (in): 3
  2. 02Baseline Pitch (angle°): 26.5651
  3. 03New Pitch (angle°): 14.0362
  4. 04Pitch (angle°) decreases by 47.2% → use this sensitivity to plan for real-world variation.
02 · PATTERN

Rise (in) doubled

rise = 12 (from 6)

Keep every other input at its default and double the rise (in). See how pitch (angle°) responds.

  1. 01New Rise (in): 12
  2. 02Baseline Pitch (angle°): 26.5651
  3. 03New Pitch (angle°): 45
  4. 04Pitch (angle°) increases by 69.4% → use this sensitivity to plan for real-world variation.
03 · PATTERN

Run (in) halved

run = 6 (from 12)

Keep every other input at its default and halve the run (in). See how pitch (angle°) responds.

  1. 01New Run (in): 6
  2. 02Baseline Pitch (angle°): 26.5651
  3. 03New Pitch (angle°): 45
  4. 04Pitch (angle°) increases by 69.4% → use this sensitivity to plan for real-world variation.
04 · PATTERN

Run (in) doubled

run = 24 (from 12)

Keep every other input at its default and double the run (in). See how pitch (angle°) responds.

  1. 01New Run (in): 24
  2. 02Baseline Pitch (angle°): 26.5651
  3. 03New Pitch (angle°): 14.0362
  4. 04Pitch (angle°) decreases by 47.2% → use this sensitivity to plan for real-world variation.
§05FAQ

Frequently asked questions

Yes. The calculator implements the standard formula as documented and returns exact floating-point results. No approximations are used unless noted in the formula.
Your feedback

How useful was this calculator?

Your ratings stay in your browser — they help us learn which tools people actually rely on.

Rate it
Was this helpful?