PITCHWRIGHT

Pitchwright Framing Calculator

Rafters, hips, jacks, stairs, board feet, sheets and concrete. Offline.

Free to try for 7 days, then unlock Pro once. No subscription.

Pitchwright on an Android phone: Common rafter

What it does

Pitchwright is a construction calculator for carpenters, framers, roofers, deck builders and remodelers. It works like a hardware calculator: a green chassis, real keys and a clear LCD, with each answer labelled so you know what you are reading. Enter dimensions the way you read them off the tape, in feet, inches and fractions or in metric.

Roof framing

Rise, run, diagonal and pitch: enter any two and solve the rest
Pitch as x in 12, or from an angle in degrees
Common rafter length, less half the ridge
Plumb and level cut angles
Regular hip or valley length, hip run and hip plumb angle
Jack rafters at 16, 24 or any spacing, each step shorter by the common difference
Rafter tail from the overhang, and the rafter with tail

Stairs

Riser count, riser height, tread count and tread depth from the total rise
Total run, stringer length, stair angle and the 2R + T check
Set a desired riser or a fixed tread
Limits from the US residential code (IRC) or the Dutch building code, with a warning when a tread falls short

Lumber and materials

Board feet from thickness × width × length, or cubic metres
Stud count for a wall at the stored spacing
Whole 4 x 8 sheets, roofing squares and 8 x 16 blocks for an area
Concrete volume in cubic yards, cubic feet and cubic metres, and bags of 80, 60 and 40 lb (25 kg in metric) with a waste allowance

Trim and layout

Crown moulding miter and bevel for 38 and 45 degree spring angles, at any corner
Circles: diameter, circumference and area
Polygon side length and miter for 3 to 64 sides
Arcs and arches from a chord or angle: arc length, height and radius

Works the way you do

Feet-inch-fractions, and millimetres and metres throughout
A results strip shows every solved value at once
10 memories, a tape of your calculations, reference tables and a key guide
Large keys you can hit with gloves on

Worked examples

Common rafter. 6:12 pitch, 12 ft run -> common rafter 13-5 (then less ridge).
Stair layout. 10'-1" rise, 15'-5" run -> 16 risers of 7 9/16, 15 treads.
Hip valley. 6:12 pitch, 12 ft run -> hip or valley 18-0.
Jack rafters. Jacks at 16 in OC on 6:12 -> common difference 17 7/8.
Crown miter. Crown, 38 degree spring on a 90 degree corner -> miter 31.62.
Metric rafter. Metric: 30 degree pitch, 4 m run -> rafter 4619 mm.

How it's calculated

Every trade key and the formula behind it, as shown in the app's key guide. A second legend is the shifted function.

Pitch °Pitch / Cut angles: Stores the typed pitch as x in 12, or solves pitch = rise ÷ run; shifted gives the plumb cut atan(pitch ÷ 12) and level cut 90° − plumb.
Rise Hip/VRise / Hip or valley: Stores the typed rise, or solves it from two of run, diagonal and pitch; shifted gives the regular hip or valley = run × √(2 + (pitch ÷ 12)²).
Run JackRun / Jack rafters: Stores the typed run, or solves it from two of rise, diagonal and pitch; shifted steps through jack rafters, each shorter by spacing × √(1 + (pitch ÷ 12)²).
Diag TailDiagonal / Rafter tail: Diagonal or common rafter = run × √(1 + (pitch ÷ 12)²), then less half the ridge; shifted stores the typed overhang or gives the tail = overhang × the same factor.
Stair TreadStairs / Tread and code: Lays out a stair for the stored rise: risers = rise ÷ desired riser, rounded and kept within the code; a typed length sets the desired riser. Shifted sets the tread or switches code.
BdFt CrownBoard feet / Crown moulding: Board feet = thickness × width × length ÷ 144 cubic inches, or cubic metres under metric; shifted gives crown mitre and bevel for the typed or stored corner.
OC StudsOn-centre spacing / Stud count: Stores the typed spacing, or steps through 16, 24 and 12 inches (400, 600, 300 mm); shifted gives studs = ⌈wall ÷ spacing⌉ + 1 for the typed wall length.
Area SheetsArea / Sheets and blocks: Stores the typed area; shifted gives whole sheets = ⌈area ÷ sheet⌉, roofing squares = area ÷ 100 square feet and blocks.
Conc BagsConcrete volume / Concrete bags: Stores the typed volume, or area × a typed thickness, in cubic yards or metres; shifted gives bags = volume ÷ bag yield plus the typed waste percent.
Circle ArcCircle / Arc: A typed length sets the radius, a plain number the polygon sides; then side = 2R × sin(180° ÷ n), diameter, circumference and area. Shifted solves an arc from a chord or angle.

Results are computed from the formulas shown for each function and are provided for reference only. Verify all dimensions before cutting or building, and confirm stair and structural requirements against the code in force and the authority having jurisdiction. The developer accepts no liability for loss or damage arising from use.

Get Pitchwright

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In het Nederlands

Sporen, hoekkepers, trappen, houtvolume, platen en beton. Offline.

Pitchwright is een bouwrekenmachine voor timmerlieden, dakdekkers, terrasbouwers en verbouwers. Hij werkt als een echte rekenmachine: een groene behuizing, echte toetsen en een helder LCD-scherm, met bij elk antwoord een label zodat u weet wat u leest. Voer maten in zoals u ze van de rolmaat afleest, metrisch of in voet, inch en breuken.

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