Web calculators
Run the number here. Cut with the app.
Five free construction calculators that work in any browser. Each one returns an estimate rounded to 1/16″, keeps nothing you type, and links to the exact 1/64″ result in Span64.
Pick a job
Five web calculators
- 01
Feet Inch Fraction Calculator
Add or subtract two feet-inch-fraction dimensions.
- 02
Board Foot Calculator
Thickness, width and length into board feet and lumber cost.
- 03
Stair Stringer Calculator
Total rise into riser count, riser height, run and stringer.
- 04
Concrete Yards Calculator
Slab volume in cubic yards, bag count and waste allowance.
- 05
Rafter Calculator
Pitch and run into common rafter length, rise and plumb cut.
What the web cannot do
Estimate here, exact in the app.
These pages round to 1/16″ and do one job at a time. They have no Tape, no keypad and nothing is saved between visits. Span64 on iPhone and iPad does the same arithmetic on exact 1/64″ integers, keeps every result on a Tape you can reuse, and needs no signal.