This site started as a roof pitch calculator and grew. Today it hosts a small suite of free residential construction calculators covering the math most DIYers and small contractors actually need. None of them require an account or a download. All of them work on phones.
This is a tour of the suite — what each calculator does, when to use it, and how they connect.
Roof pitch calculator (the original)
The main calculator on the home page handles five distinct calculation modes: rise and run to pitch ratio, pitch ratio to angle in degrees, angle to pitch ratio, roof surface area from footprint and pitch, and rafter length from run and pitch. It accepts inches, feet, centimetres, or metres on input. On mobile, it can use the phone's tilt sensor to read the pitch directly off a roof or a rafter.
Use it for: any time you need to convert between pitch formats, calculate roof area for a material order, or measure an existing roof from your phone.
Wall stud calculator
On the wall stud calculator page, you input wall length, stud spacing (12, 16, or 24 inches on center), number of openings, studs per opening, number of corners, studs per corner, and waste factor. The output is total stud count broken into base studs, opening allowances, corner allowances, waste, and total to order.
Use it for: framing any wall — exterior, interior, single-story or stacked. The calculator handles California corners, three-stud corners, and typical residential opening framing.
Siding calculator
The siding calculator handles rectangular wall sections plus gable triangles for any pitch. You input building length, building width, wall height, gable count, roof pitch, total opening area, and waste factor. The output is total siding area broken down by section, with total order quantity in square feet and squares.
Use it for: ordering lap siding, sheet siding, board-and-batten, or any wall finish. The gable triangle math is the part most homeowners miss when calculating manually.
Roof sheathing calculator
For roof sheathing, you input building length and width, roof pitch, roof type (gable, hip, shed), sheet size (4×8, 4×9, or 4×10), waste factor, and optional cost-per-sheet. The output is footprint, slope factor, surface area, base sheet count, waste, total sheets, and estimated material cost if you provided a per-sheet price.
Use it for: ordering plywood or OSB roof decking. The calculator works for any roof type since the underlying math is the same — footprint times slope factor.
Hip roof square footage calculator
Hip roof calculations are the same as gable roofs for surface area (footprint × slope factor) but typically need higher waste factors because of the angled cuts at every plane intersection. The hip-roof calculator outputs surface area, squares, hip rafter length, and recommended bundle count for asphalt shingles.
Use it for: hip roof material orders, especially when you also need the hip rafter length for framing.
Road gradient calculator
A side-tool that accepts rise/run, percent grade, or angle in degrees and converts between all three formats. Includes a classification chart with common road and ramp grade thresholds.
Use it for: driveway design, retaining wall and ramp work, or any time you need to bridge between the road-construction world (percent grades) and the roof-and-framing world (rise/12 and degrees).
LVL beam sizing reference
A first-pass LVL beam sizing tool for residential framing. You input span, load type (header, floor beam, roof beam), tributary width, and snow load (for roof beams). The output is calculated minimum depth, standard depth rounded up, recommended ply count, and a starting size in standard nomenclature.
Use it for: budget-stage estimating and sanity-checking engineering. The tool flags conditions that require an engineer (long spans, heavy tributary widths, deep beams). For any non-prescriptive condition, validate the output with a structural engineer before building.
Roof replacement cost calculator
For estimating a complete roof replacement project: building dimensions, pitch, material (9 options), region (3 cost tiers), complexity (3 levels), and tear-off requirements. Output is roof surface area, squares, and a low/typical/high cost range.
Use it for: budget planning before getting contractor quotes, or sanity-checking quotes you have received. The output is intended to be a defensible budget range, not a final price.
How they connect
The calculators share underlying math. The pitch calculator outputs the slope factor that the sheathing, siding, and cost calculators use as an input. The rafter length calculator output is what you would order if you were stick-framing the roof the sheathing calculator outputs material for. The wall stud calculator output is what frames the building the siding calculator wraps.
In practice, you can sketch a rough project on paper, dimension it, and walk through the calculators in order — pitch, wall studs, siding, sheathing, roofing, cost — to produce a complete budget estimate in under an hour. The accuracy is good enough for early-stage planning. For final material orders, get a contractor quote and compare against the calculator output as a sanity check.