Free construction calculators in feet, inches and fractions.
Add feet and inches, turn a decimal into a tape measure fraction, find a diagonal, convert roof pitch to degrees, lay out stairs and work out square footage. Each tool gives the answer in exact fractions with the formula written out. No signup.
Free online construction calculators
Each one answers its question in full, in the browser, with nothing blurred or locked. The app adds stair code reports, hips and valleys, and a tape that keeps every entry.
/CALCULATORS/ROOF-PITCH/
Roof pitch calculator
Convert any roof pitch to degrees, percent grade, slope ratio, and rafter factor. Add a run and it gives the rafter length.
/CALCULATORS/STAIRS/
Stair calculator
Riser height, tread depth, number of steps, total run, stair angle, and stringer length. Checks limits against IRC 2021.
/CALCULATORS/SQUARE-FOOTAGE/
Square footage calculator
Rooms, walls, floors, and irregular shapes. Enter feet and inches, get sq ft, sq yd, and sq m. Running total included.
/CALCULATORS/FEET-INCHES/
Feet and inches calculator
Add, subtract, multiply, and divide measurements in fractions. Exact to a sixty-fourth, with the working shown.
/CALCULATORS/INCHES-TO-FRACTION/
Inches to fraction calculator
Convert a decimal inch, decimal feet or millimetres to the nearest mark on a tape, from 1/8 to 1/64, with the error shown.
/CALCULATORS/RIGHT-TRIANGLE/
Diagonal calculator
Find a diagonal, a missing side, or how far a corner is out of square, in feet and inches. The 3-4-5 rule, worked out.
Already know your pitch? The roof pitch to degrees chart lists every pitch from 1/12 to 24/12 with its angle, percent grade and pitch factor, and the roof pitch multiplier table gives the rafter, hip and valley multipliers.
Three things these calculators do differently
Exact fractions, not decimals
Fractions are carried at full precision and rounded once, on the way to the screen. A riser of 7-3/16 in is 7-3/16 in from the input to the cut, not 7.1875 rounded twice.
Shows the working
Every result opens into the named formula with your own numbers substituted into it. You can check the arithmetic by eye without trusting the tool.
Every code limit sourced
Code limits are printed with their section number and the margin. You always know which book a number came from and how close you are.
Download the Sawline app for the full jobsite tool
The website answers one question at a time. The app carries the roof and the stair: rafters, hips and valleys, stair stringers with code reports, and area and volume, and it works with no signal.
Roof pitch and rafters
Pitch to degrees, grade and ratio. Any two of rise, run, diagonal and pitch give the other two, and HIP/V gives the hip or valley.
Stair layout and code check
One rise in, the whole flight out. The app sizes the stringer, checks each value against the ruleset, and prints the section number.
Code report with section numbers
Every row names the value, the limit, and the section it came from — including rows that pass. No guessing where a number came from.
What is in the app
Roofs, stairs, and area and volume in one app. Monthly with a 3-day free trial, or a one-time lifetime purchase.
Framing & roofing
Rafters, hips, valleys
Any two of rise, run, diagonal and pitch solve the other two. HIP/V gives the hip or valley length, its plan run, its angle and the backing bevel.
Stairs
Solved, then checked
Run-limited or riser-limited, with "it does not fit" treated as a real answer. Risers, treads, total run, and the stringer's length and angle.
Area and volume
Three dimensions in
Length, width and height give area and volume. A diameter gives a circle's area and circumference.
Built for the jobsite
Works with no signal
Everything runs on the device. Screen stays awake, keys sized for gloves, and an outdoor theme for bright sun.
