Carpenter Calculators

How to use these carpenter estimates

These tools cover different tasks. Choose the measurement unit first and use the same unit throughout each calculation. Results are planning estimates; check timber sizes and actual stock before purchasing or cutting.

Board feet: a worked example

The nominal board-foot formula is thickness in inches × width in inches × length in feet ÷ 12. For a board measured as 1 in × 6 in × 8 ft, the result is 1 × 6 × 8 ÷ 12 = 4 board feet. Multiply by the number of boards to estimate total volume-based quantity. Actual lumber may be sold using local nominal or finished dimensions, so confirm the seller's pricing method.

Cut lists: why the result is only a starting point

The cut-list estimate adds all requested lengths and applies your chosen waste allowance, then divides by stock length. It does not arrange cuts on individual boards. Saw-blade kerf, grain direction, knots, defects, minimum offcut sizes and whether a cut can be rotated can change the number of stock pieces required. Plan the actual cutting pattern before buying expensive material.

Room material estimates

The room tool assumes a rectangular room and identical rectangular pieces. It does not account for pattern alignment, openings, grout, joint gaps, edge trimming or different pieces around corners. For tile flooring, use the dedicated Tile Calculator, which includes a separate wastage allowance.

Staircase estimates are not a design

The staircase result estimates riser count and approximate horizontal run from the inputs. It does not check headroom, landings, handrails, code limits, structural support or the available floor opening. Have a qualified professional verify the complete stair layout against applicable local requirements before construction.