Formulas shown · Sources cited
Free construction calculators for the trades
Calculators that show their work, for material takeoffs and code checks: roofing squares, studs and plates, drywall sheets, paint gallons, wire size and voltage drop, pipe offsets, BTUs, tile and gravel.
- Type 12' 6-1/2", 150 in or 3.8 m
- Results update as you type, with no sign-up
- Quantities round up the way a supplier sells them
- NEC, IRC, IPC and IECC tables cited by edition and section
Step 1 · Pick your trade
What are you working on?
Roofing & siding calculators
Roof area, shingle bundles, metal panels and siding squares from a footprint and pitch.
Framing & carpentry calculators
Studs, plates, headers, sheathing, decking and board feet for wall and deck framing.
Drywall calculators
Sheets, joint compound, tape, screws and corner bead for any room.
Painting & wallcovering calculators
Gallons of paint and primer by surface, plus wallpaper rolls.
Electrical calculators
Wire size, voltage drop, box fill, dwelling load and Ohm’s law, with NEC table references.
Plumbing calculators
Pipe offsets, drain slope and water heater sizing for rough-in work.
HVAC & insulation calculators
BTU sizing and insulation quantities by R-value and climate zone.
Flooring & tile calculators
Tiles, boxes, thinset, grout and flooring cartons with pattern waste.
Landscaping & hardscape calculators
Gravel, mulch, topsoil and pavers by the yard and the ton.
Most used
Popular calculators
Reference
Charts and code tables
Look-up tables for the job: the same numbers the calculators use, with the code edition and section they come from.
Guides
Answers behind the numbers
Accuracy
How the numbers are checked
Written spec first
Each calculator starts as a written specification: the sources, the equations, the rounding rules and at least four worked examples solved by hand.
Tests against the examples
The code must reproduce every worked example, and the page you see is tested as built, with the diagram checked for scale.
One source of truth
Chart pages and calculators read the same constants, so a table on this site can never disagree with the tool beside it.
Read the methodology and the corrections log. Found an error? Every page has a report link. Tradesman Calculator is estimates only; confirm quantities with your supplier and requirements with your local code official.