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A2 · Woodworking calculator

Timber Length, Volume & Cost Calculator

Turn a quantity of equal finished pieces into a checked stock-length estimate, purchased timber volume and optional cost. Structural sizing remains outside this calculator.

Free to use · no account needed · calculations stay in this browser · formula reviewed 4 September 2026

Enter finished pieces and stock

Use actual section sizes and one repeated finished length. The stock check includes kerf and trim but does not choose structural timber.

Usable stock length removes trim at both ends. Equal-piece fit includes kerf between adjacent pieces. Purchased volume uses the full stock length and entered section.

Example result using the values shown

Finished length
5.76 m
Length with allowance
6.34 m
Equal pieces per stock length
3
Stock lengths to plan for
3
Purchased length
7.20 m
Purchased volume
0.0301 m³
Estimated cost
£25.50

Three 720 mm pieces fit each trimmed stock length with two 3.2 mm kerfs. Defects and the final cutting sequence still need a workshop check.

  • 8 equal pieces at 720 mm; 95 × 44 mm section.
  • 2400 mm stock; 3.2 mm kerf; 10 mm end trim; 10% allowance.

Use this as a stock estimate for equal pieces

  1. Enter the finished length and number of identical pieces.
  2. Enter actual stock length and section dimensions.
  3. Add measured kerf, deliberate end trim and a named allowance.
  4. Check defects, machining and the real cutting sequence before buying.

This calculator does not size joists, rafters, studs, beams, decking or other structural members.

Worked example

Eight 720 mm pieces total 5.76 m. A 10% allowance gives 6.336 m. After 10 mm trim at each end, a 2400 mm stock length holds three pieces with two 3.2 mm kerfs, so three stock lengths are needed. At 95 × 44 mm, the gross purchased volume is 0.030096 m³.

Blank stock check

Section_____ × _____ mm
Finished pieces_____ × _____ mm
Stock length_____ mm
Kerf / end trim / defects____________________