Building & Measurement Calculators
These are the layout tools — the ones you use with a tape measure in one hand. Convert a footprint into roof squares, work out whether a staircase fits the code, turn a cut list into board feet, add up the square footage of an awkward floor plan. The formulas are shown on the page so you can check them yourself, and code-related numbers tell you where to confirm with your local building department.
Quick answer: This category holds 9 free calculators. Each one takes your measurements and unit prices and returns an order quantity or cost estimate in your browser — nothing is uploaded and no account is needed.
Square Footage Calculator
Add up rooms and shapes to get total square feet, with an optional waste allowance included.
Square Footage Cost Calculator
Multiply a square footage figure by your own price per square foot to get project cost.
Lumber Calculator
Count studs, joists or boards and get board feet, total linear feet and a lumber cost range.
Board Foot Calculator
Work out board feet from thickness, width and length for hardwood sold by the board foot.
Roof Pitch Calculator
Turn roof rise over 12 inches of run into degrees, slope percentage and an area multiplier.
Rafter Length Calculator
Get common rafter length from building width, roof pitch and overhang, plus ridge and count.
Shingle Calculator
Turn roof area or footprint and pitch into squares, bundles, underlayment, ridge cap and nails.
Stair Calculator
Turn a total rise into riser count, riser height, tread run, stringer length and code notes.
Retaining Wall Calculator
Get blocks, caps, base and drainage gravel, and a cost range for a block retaining wall.