Free construction calculators that show the working.
Roof pitch, stairs, square footage, and feet and inches — each tool solves one problem in full, in the browser, with exact fractions and the formula written out. No signup, no blurred results, nothing held back.
Free online construction calculators
Each one answers its question in full, in the browser. Nothing is blurred, nothing is held back. Use them as they are, or download the app for more: 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. Includes the full 1/12 to 24/12 pitch chart.
/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.
Already know your pitch? The roof pitch chart lists every pitch from 1/12 to 24/12 with its angle, percent grade and rafter factor, and the rafter factor table gives the number you multiply a run by to get the rafter length.
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. One purchase, or a monthly if you would rather.
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.
