Construction Guru User's Guide

Getting Started

Construction Guru is a professional construction calculator with three modules: Core, Framing, and Tools. Switch between them using the tabs at the top of the screen.

• 30-day free trial gives you full access to everything
• After the trial, Core stays free; Framing and Tools require a one-time $19.99 purchase
• All settings are in the gear icon (top right)

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Core Module

The Core module handles everyday construction math: dimensions, area, volume, right-angle solving, and unit conversions.

Number Entry

Type numbers with the keypad. Use the unit keys along the bottom of the function rows to assign units:

• ft - feet
• in - inches
• / - fraction
• m - meters
• mm - millimeters
• yd - yards (in Core function row)

Example: To enter 5 feet 6-1/2 inches, type: 5 ft 6 . 5 in or 5 ft 6 in / 1 / 2

The secondary display line always shows alternate formats (decimal, metric equivalent).

Right-Angle Solver

Store any two of these values, and the calculator solves the rest:

Key	What It Stores
Length	First dimension
Width	Second dimension
Height	Third dimension
Area	Calculates Length x Width
Volume	Calculates Length x Width x Height

For right-angle problems, use the Framing module’s Pitch, Rise, Run, and Diagonal keys.

Store-Value Keys

Keys like Length, Width, and Height work as latch/unlatch toggles:

1. Enter a value, then press the key to store it
2. The key shows the stored value on its face
3. Press the key again (with nothing new entered) to clear it

Double-Clear

• Press C once - clears current entry
• Press C twice (on empty display) - clears all stored function values (Length, Width, Height, Rise, Run, Diagonal, Pitch)

Convert Key

Press Convert with a value displayed to see it interpreted as every unit type.

Triangle Solver

Press Triangle to open the guided triangle solver. Enter any 3 values (sides or angles) and it solves the rest.

Supported modes (auto-detected):

• SSS - 3 sides known
• SAS - 2 sides + included angle
• ASA - 2 angles + included side
• AAS - 2 angles + non-included side
• SSA - 2 sides + non-included angle (may have 2 solutions)

Toggle Right Triangle to lock one angle at 90 degrees.

Results include all sides, all angles, area, perimeter, and heights. The diagram updates live as you enter values.

Plus/Minus Key

Press +/- to negate the current value. Useful for calculating differences and offsets.

Memory (9 Slots)

• M+ then a digit (1-9) - stores the current value in that slot
• MR then a digit (1-9) - recalls the value from that slot
• Press C to cancel if you pressed M+ or MR by accident

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Framing Module

The Framing module provides specialized construction calculators for framing, roofing, stairs, and fencing. Each function key opens a guided calculator with live-updating results.

Right-Angle Solver Keys

Key	What It Stores
Pitch	Roof pitch (rise per 12 units of run)
Rise	Vertical dimension
Run	Horizontal dimension
Diagonal	Slope distance (hypotenuse)

Enter any two and the calculator solves the remaining values, showing:

• Rise, Run, Diagonal (in feet-inches-fractions)
• Angle (degrees, minutes, seconds)
• Pitch (rise/12 format)
• Grade percentage

Rafter Calculator

Calculates common rafter dimensions including bird’s mouth cuts.

Inputs:

• Building Span (full width wall-to-wall)
• Pitch (rise per 12)
• Overhang (horizontal projection past the wall)
• Ridge Thickness
• Rafter Size (2x6, 2x8, 2x10, 2x12)
• Plate Width (2x4 or 2x6)
• Building Length and Rafter OC Spacing (optional, for material counts)

Results:

• Run, Rise, Rafter Length, Total Length with overhang
• Bird’s Mouth: Seat Cut, Plumb Cut, HAP (Height Above Plate)
• Overhang tail length
• Plumb angle for saw settings
• Material counts (rafter count, standard board length, ridge board)
• Step-by-step cutting guide

Code Check: Warns if HAP is less than 3-1/2” (limits insulation depth at eave).

Hip/Valley Rafter Calculator

Calculates hip or valley rafter geometry.

Inputs:

• Building Span, Pitch, Overhang, Ridge Thickness
• Rafter Size, Plate Width
• Hip or Valley selection
• Jack OC Spacing

Results:

• Hip/Valley run, rise, and total length
• Cheek cut angle (compound miter at ridge)
• Backing angle
• Jack rafter lengths at each OC position
• Bird’s mouth dimensions

Stair Calculator

Designs code-compliant stairs with optional landing.

Inputs:

• Floor-to-Floor Rise
• Tread Depth and Thickness
• Floor Thickness (for headroom calculation)
• Stair Width
• Building Code: IRC (residential) or IBC (commercial)
• Add Landing toggle

Results:

• Riser count and actual riser height
• Tread count and total run
• Stringer length (or per-flight lengths if landing)
• Stringer drop (trim from bottom)
• Throat depth
• Incline angle
• Minimum stairwell opening (headroom clearance)
• Material counts: stringers, treads, risers
• Handrail length

Code Limits:

	IRC (Residential)	IBC (Commercial)
Max Riser Height	7-3/4”	7”
Min Tread Depth	10”	11”
Max Flight Rise	12’ 3”	12’ 0”
Min Headroom	6’ 8”	6’ 8”

If total rise exceeds the maximum flight rise, the calculator automatically splits into two flights with a landing.

Stud Calculator

Calculates stud count and materials for wall framing.

Inputs:

• Wall Length and Height
• Spacing: 12”, 16”, 19.2”, or 24” OC
• Add End Stud toggle

Results:

• Stud count
• Actual OC spacing
• Board feet (2x4 at wall height)
• Drywall sheets needed (4x8)
• Top/bottom plate guidance (IRC R602.3.2)

Floor Joist Calculator

Calculates joist layout with code compliance.

Inputs:

• Joist Span, Room Width
• Spacing: 12”, 16”, 19.2”, 24” OC
• Joist Size: 2x6, 2x8, 2x10, 2x12
• Center Beam toggle
• Lumber Species

Results:

• Joist count and actual OC spacing
• Max allowable span per IRC Table R502.3.1(1)
• Code compliance badge

Baluster Calculator

Calculates baluster spacing to meet code.

Inputs:

• Railing Length
• Baluster Width
• Post Width
• Start/End Post toggles

Results:

• Baluster count
• Gap between balusters
• Code compliance (4” max gap per IRC R312)

Fence Project Planner

Plans multi-run fence projects with gates, shared corners, and material estimates.

Inputs:

• Fence Type: Picket, Panel, or Privacy
• Fence Height
• Post Spacing, Rail Count
• Picket Width and Gap (or Panel Width)
• Post Sizes (line and gate)
• Concrete Mode: QuickSet bags, Post Foam, or None

Fence Shapes:

• Straight, L-Shape, U-Shape, U-Return, Rectangle, or Custom

Per-Run Features:

• Named runs with individual lengths
• Gates (pedestrian or vehicle) with width and position
• Shared corner posts between runs

Results:

• Post count (adjusted for shared corners and gates)
• Picket or panel count
• Rail length (total linear feet)
• Concrete bag count
• Board feet totals
• Overhead plan-view diagram

Compound Miter Calculator

Calculates saw settings for crown moulding.

Inputs:

• Spring Angle (angle moulding sits at, typically 45 degrees)
• Corner Angle (angle between walls, typically 90 degrees)

Results:

• Miter angle (set on saw)
• Bevel angle (table tilt)
• Reference table for common corner angles

Rake Wall Calculator

Calculates stud lengths for gable-end walls.

Inputs:

• Wall Span, Pitch
• Spacing: 16” or 24” OC
• Starting Height
• Centered toggle

Results:

• Individual stud lengths at each position
• Total stud count
• Peak height
• Total board feet

Roofing Estimator

Estimates roofing materials.

Inputs:

• Building Length and Width
• Pitch
• Roof Shape: Gable, Hip, Gambrel, Shed, or Flat
• Waste percentage
• Overhang
• Underlayment type

Results:

• Roof area (plan and actual after slope)
• Shingle squares and bundles
• Decking sheets (4x8)
• Underlayment rolls
• Starter strip, ridge cap, and drip edge (linear feet)

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Tools Module

Trigonometry

Six trig function keys for angle and ratio calculations:

• sin, cos, tan - enter angle in degrees, get ratio
• asin, acos, atan - enter ratio, get angle in degrees

Example: 30 sin = 0.5 Example: 0.5 asin = 30

Board Feet Calculator

Press BdFt to open the board feet calculator.

Inputs:

• Thickness (nominal, inches)
• Width (nominal)
• Length (feet)
• Quantity
• Price per board foot (optional)

Formula: Board Feet = (Thickness x Width x Length) / 144

Circle & Arc Calculator

Press Arc to calculate circle and arc measurements.

Inputs:

• Radius
• Central Angle (0-360 degrees)

Results:

• Arc length, chord, sagitta
• Sector area, segment area
• Full circle: diameter, circumference

Percentage and Square Root

• % - percentage calculations
• sqrt - square root of displayed value

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Settings

Open Settings with the gear icon in the top right.

Units

• Default Units - Imperial, Metric, or Mixed
• Field Default Unit - what bare numbers mean in dimension fields (feet, inches, yards, or none)
• Fraction Resolution - precision for fractional display: 1/4”, 1/8”, 1/16”, 1/32”, or 1/64”

When a result falls between fraction marks, the display shows a rounding indicator:

• Strong (e.g., “strong 3/16”) means the actual value is slightly over the displayed fraction
• Shy (e.g., “shy 3/16”) means it’s slightly under

Appearance

Choose from 4 color themes and 6 button styles:

Themes:

• Classic - traditional navy and orange
• Blueprint - technical drawing aesthetic with subtle grid
• Dark Pro - dark mode for indoor/evening use
• Fieldwork - high-contrast earth tones for outdoor visibility

Button Styles:

• Tactile - chunky 3D keys with depth
• Physical - realistic calculator buttons
• Sculpted - beveled edges
• Raised - subtle elevation
• Soft - gentle shadow
• Flat - completely flat

Themes and button styles can be mixed independently.

General

• Keep Screen On - prevents screen lock while measuring on-site (uses more battery)

Purchase

• Shows trial status and days remaining
• Unlock Full Access button with price
• Restore Purchase for reinstalls or new devices

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Paperless Tape

The tape records your calculation history during a session.

• Tap Tape (N) below the display to expand/collapse
• Each entry shows the expression and result
• Tap the recall button on any entry to load that value back
• Share the full tape as text
• Tape holds up to 20 entries (oldest drops off)
• Tape clears when you close the app

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Sharing Results

Every guided calculator includes:

• Copy Results - copies calculation summary as text to your clipboard
• Share Card - generates a professional-looking image card with diagram, inputs, results, and code compliance badges

Share cards include a navy header with the calculator name, a visual diagram, all results, and a “Generated by Construction Guru” footer. They’re designed to look professional when shared with clients, contractors, or building inspectors.

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Tips and Shortcuts

• Double-tap the result to quickly copy it to clipboard
• Fraction grid - press / to see a quick-select grid of common fractions (1/2, 1/4, 3/8, etc.)
• F/D toggle - press the in key on a displayed result to toggle between fractional and decimal inches
• Convert - quickly see any value in every unit system
• Auto-save - guided calculators save your inputs when you close them and restore when you reopen
• Clear button in guided calculators resets all inputs to zero

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Quick Examples

Example 1: Add Feet and Inches

25 ft + 23 ft 8 in =

Result: 48’ 8” (with secondary display showing 584” | 14,833.6 mm)

Example 2: Find a Rafter Length

1. Switch to Framing module
2. Press Rise, enter 6 ft
3. Press Run, enter 12 ft
4. Display shows: Diagonal = 13’ 5-1/16”, Pitch = 6/12, Angle = 26.57 degrees

Example 3: Design Code-Compliant Stairs

1. Switch to Framing module
2. Tap Stair
3. Enter Floor-to-Floor Rise: 9 ft 2 in
4. Select IRC (residential)
5. Results update instantly with riser count, heights, and code badge
6. Tap Share Card to send to your crew

Example 4: Calculate Board Feet

1. Switch to Tools module
2. Tap BdFt
3. Enter: 2” thick, 6” wide, 8’ long, quantity 24
4. Results: 192 board feet, plus cost if price entered

Example 5: Store and Recall a Measurement

1. Calculate a value (e.g., a diagonal = 13’ 5-1/16”)
2. Press M+ then 3 (stores in slot 3)
3. Do other calculations
4. Press MR then 3 (recalls the stored value)
5. Continue calculating with the recalled value

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Keyboard Reference

Core Module Keys

Row	Keys
Function 1	Length, Width, Height, Area, Volume
Function 2	yd, Convert, Triangle, +/-
Units	ft, in, /, m, mm
Numbers	7 8 9 / C
	4 5 6 x Backspace
	1 2 3 - MR
	0 . = + M+

Framing Module Keys

Row	Keys
Function 1	Pitch, Rise, Run, Diagonal, Rafter
Function 2	Hip/Val, Miter, Rake, Roofing
Function 3	Stair, Baluster, Studs, Joists, Fence
Units	ft, in, /, m, mm

Tools Module Keys

Row	Keys
Function 1	sin, cos, tan, asin, acos, atan
Function 2	BdFt, Arc, %, sqrt, +/-
Units	ft, in, /, m, mm