Roof Truss Height Calculator

Calculator inputs

Use rise over run, such as 6 over 12.

Unit System

Building Span

Pitch Rise

Pitch Run

Heel Height

Overhang

Building Length

Truss Spacing

Decimal Precision

Reset

Formula used

Half Span = Span ÷ 2

Roof Rise = Half Span × (Pitch Rise ÷ Pitch Run)

Total Truss Height = Roof Rise + Heel Height

Slope Angle = arctan(Pitch Rise ÷ Pitch Run) × 180 ÷ π

Common Rafter Length = √(Half Span² + Roof Rise²)

Top Chord Length = √((Half Span + Overhang)² + ((Half Span + Overhang) × Pitch Ratio)²)

Approximate Roof Surface = 2 × Top Chord Length × Building Length

Estimated Truss Count = floor(Building Length ÷ Spacing) + 1

This calculator uses simplified geometric relationships for planning. It is helpful for estimating height, rise, angle, member length, and approximate roof coverage before detailed design review.

How to use this calculator

Choose feet or meters.
Enter the full building span from wall to wall.
Enter the roof pitch as rise over run.
Provide heel height and overhang values.
Optionally add building length and spacing for extra outputs.
Select the number of decimals you want.
Click the calculate button to show the result above the form.
Use the CSV and PDF buttons to export the report.

Example data table

#	Span (ft)	Pitch	Heel (ft)	Overhang (ft)	Rise (ft)	Total Height (ft)	Angle (°)	Rafter Length (ft)
1	24.00	6:12	0.50	1.00	6.00	6.50	26.57	13.42
2	30.00	8:12	0.75	1.50	10.00	10.75	33.69	18.03
3	36.00	4:12	0.50	1.00	6.00	6.50	18.43	18.97
4	40.00	10:12	1.00	2.00	16.67	17.67	39.81	26.03

These sample rows are for illustration and quick comparison.

FAQs

1) What is roof truss height?

Roof truss height is the vertical distance from the bearing point or heel reference to the ridge peak. It helps size the attic space, determine roof appearance, and estimate framing members.

2) How does pitch affect the height?

A steeper pitch increases rise for the same span, which raises the ridge and increases truss height. Lower pitch reduces height and usually shortens the vertical rise.

3) Does overhang change the truss height?

Overhang usually does not change the ridge height itself. It extends the top chord beyond the wall line and affects member length, eave position, and roof surface estimates.

4) Why is heel height included?

Heel height adds vertical space at the wall plate. It is useful for insulation depth, ventilation planning, and more accurate overall truss geometry in many practical roof layouts.

5) Can I use this for metric projects?

Yes. Switch the unit selector to meters and enter all linear dimensions consistently in meters. The pitch ratio stays unitless because rise and run use the same base unit.

6) Is this enough for structural approval?

No. This tool is for estimating and planning. Final truss design should be checked against loading, connections, local code requirements, material grade, and engineered drawings.

7) What spacing value should I enter?

Enter the center-to-center distance between trusses along the building length. Common spacing values depend on design practice, loading, sheathing, and local construction standards.

8) Why are rafter length and top chord length different?

Common rafter length measures ridge to wall geometry. Top chord length can include overhang, so it may be longer. That makes the two numbers different in many layouts.