Truss Pitch Calculator
Convert roof pitch, rise, angle, top chord length, heel height, overhang projection, and truss layout counts for common wood roof truss profiles.
⚙Real truss layout presets
📐Pitch, rise, and layout inputs
Best when the plan set already gives a pitch such as 6/12.
Measure between the outside faces of the supporting walls or bearing points.
Enter 6 for a 6/12 pitch, 7.5 for a 7.5/12 pitch, and so on.
Vertical rise from plate line to peak before heel height.
Use when matching an existing rafter or digital angle finder reading.
Measured along one sloped chord from bearing to peak, excluding overhang.
Energy heels raise the actual peak and change shipping height.
Used only for practical chord stock allowance, not for final engineering design.
Calculated pitch
Roof angle
Rise to peak
One top chord
Truss count
Pitch class
Full breakdown
🏗Truss profile and pitch comparison grid
📊Reference tables
| Pitch | Angle | Rise on 24 ft span | Typical truss use |
|---|---|---|---|
| 2/12 | 9.5° | 2.0 ft | Porch, patio cover, low-slope metal roof |
| 3/12 | 14.0° | 3.0 ft | Shed, utility building, simple mono truss |
| 4/12 | 18.4° | 4.0 ft | Garage, shop, economical common truss |
| 6/12 | 26.6° | 6.0 ft | Residential Fink or Howe truss |
| 8/12 | 33.7° | 8.0 ft | Attic truss, steeper snow-shedding roofs |
| 10/12 | 39.8° | 10.0 ft | Steep roof, gambrel segment, bonus-room roof |
| Input source | Formula used | Best use | Field caution |
|---|---|---|---|
| Rise per 12 | angle = atan(pitch / 12) | New truss submittal or plan conversion | Use inches of rise per 12 inches of horizontal run. |
| Known rise | pitch = rise / half-span x 12 | Checking a drawn peak height | Do not include raised heel unless peak height includes it. |
| Roof angle | pitch = tan(angle) x 12 | Matching an existing roof plane | Measure along the roof plane, not fascia trim. |
| Top chord | rise = sqrt(chord² - run²) | Reverse-checking a measured chord | Chord must be longer than the horizontal run. |
| Spacing | Common span range | Layout effect | Where it appears |
|---|---|---|---|
| 12 in o.c. | High load zones | More trusses and tighter sheathing support | Heavy snow or specialty roofs |
| 16 in o.c. | Moderate roof loads | Balances count and deck support | Custom residential framing |
| 19.2 in o.c. | Engineered layouts | Five spaces per 8 ft sheet module | Production framing layouts |
| 24 in o.c. | Common roof trusses | Fewer trusses with rated sheathing spans | Garages, homes, shops |
| Chord depth | Actual depth | Typical pitch range | Planning note |
|---|---|---|---|
| 2x4 | 3.5 in | Short common spans | Often used on modest Fink trusses with normal loads. |
| 2x6 | 5.5 in | Medium spans | Common for raised heels, snow loads, and attic clearance. |
| 2x8 | 7.25 in | Longer spans | Gives more bearing and connector room in deep trusses. |
| 2x10 | 9.25 in | Special profiles | Usually design-driven rather than pitch-driven. |
💡Pitch calculation tips
If you don’t know what’s creating the sloping surface you’re measuring, there’s no way to accurately measure a roof despite a day of measuring. A truss pitch calculator isn’t just a mathematical assistant; it’s a tool for protection from expensive framing error. By turning unclear angles into real measurements, you’ll be able to see length of top chord in wood required before ever placing an order.
Pitch is typically stated as the number of vertical inches for every twelve horizontal inches. You’ll see it as 6:12 or 4:12, etc… So pitch is also known as “rise over run,” which is basicly a ratio. It’s commonly used that way by building trades, but most people simply view pitch as the visible steepness of roof.
How a Truss Pitch Calculator Helps You Build Your Roof
So here’s what that means: The calculator take that number from you and immediately calculates the angle. Why does it matter? Because there are limits to how much certain roofing and sheathing material can slope. In your head, a 6 on twelve pitch sounds moderate enough, but in geometry terms it describe an angle that measures out to be twenty-six degrees. That require a specific thickness of deck and spacing between fastener.
The table on the page puts that relationship in perspective so you don’t have to perform any trigonometry in your head…. That’s where things get real interesting: overhangs and chord length. For example, you could measure out how much wall space you have to cover. But then there’s the part sticking out past wall that protects your siding from the rain. If you’re not accounting for horizontal distance of the overhang, you’ll wind up with a bunch of rafters that fall short of the fascia board by several inches.
Once you enter width of your roof and how deep you want your eaves, the calculator do all the math for you, saving you the headache of trying to figure out what coefficients are or how to do conversions. It accounts for the fact that the hypotenuse is ALWAYS greater than horizontal run.
Another variable that catches a lot of DIYers (and even some pros) off guard is heel height. The heel is part of the truss that sits down onto the plate. A standard heel have very little space for insulation around the outside wall. Raising the heel will raise the bottom cord above the top of the wall plate, giving more depth for insulation and improving how well it save energy. But it doesn’t change the pitch of the truss at all. And it raise the overall height of the building by a bunch. Keep this in mind if you are calculating attic headroom or checking crane lift clearance during installation.
The next thing to consider is what your plans are for under the roof. For a typical shed or garage, a basic Fink truss will suffice. For a real attic where you can use space, you’re going to want a type of attic truss with its vertical web member or a scissor design for a vaulted ceiling. The profiles alter both the internal loading path and necessary size of the top chord lumber.
For residential applications, 24 inches between trusses is typical. Heavier snow loads may require closer spacing. They may also require deeper dimensional lumber, such as twelve-inch deep, or even engineered glulam beam.
Planning a roof is all about numbers, which are easy to lose track of. These tools standardize them for you. You input the variables you know (the span, and the rise you want), and out comes the rest: the peak height, chord length, and an estimate of the number of truss needed. So you can check if your plan will work within the lot dimensions before handing off plans to an engineer. The breakdown section show the impact of the pitch, explaining how small differences change the total height and volume of materials. In other words, it help strike a balance between practical considerations. Say, shipping limits or zoning setbacks, and aesthetics.
In short, roof framing is a lesson in planning ahead and being precise. You need foresight because you don’t want any headaches on the job site, and you need precision because getting it right on paper makes all the difference. You want to know exactly where the ridge sits. You want to know how long the tails has to be. You want to know if those trusses is going to clear the foundation walls.
This calculator does that for you. It runs the math, so it take things like these ratios and spits out real construction data that you can carry into the field. It makes sure that the numbers in your head are the same than the numbers that make up what you’re building. When the material limits and the geometry align, the roof stay up and the water stays out. Until people learn to trust the calculations more then their eyeballs, that’s the part they get wrong.
