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Board Foot & Timber Volume Calculator

Enter the thickness, width, length and quantity for each size of timber and get the total board feet, the volume in cubic metres, and the cost at your price. Add a row for every size on your cutting list, in millimetres and metres or in inches and feet.

Board feet

01. Boards to measure

4.1 ea41.2 bd ft

02. Waste & price

A board foot is a fixed volume of about 0.00236 m³ - one cubic metre is roughly 424 board feet. Add a row for each size, enter how many of each, and the total board feet, the volume and - if you set a price - the cost all add up below. Timber is figured at its nominal size, so enter a 45 × 90 as 45 by 90. Leave the price at 0 to skip the cost.

Total board feet
41.2bd ft

Volume (m³)

0.097 m³

Pieces

10

41.2 bd ft ≈ 0.097 m³.

Guide & worked example

How this calculator works

A board foot is a measure of timber volume: the amount of wood in a piece 1 inch thick, 12 inches wide and 1 foot long, which is 144 cubic inches. Because it is a volume, it captures thickness, width and length all at once - the way sawmills and timber yards price rough and hardwood stock. The classic shop formula works in inches and feet:

board feet (one piece) = thickness_in × width_in × length_ft ÷ 12
row total              = board feet per piece × quantity
total                  = sum of every row
to order               = total × (1 + waste %)
cost                   = board feet to order × price per board foot

1 board foot = 144 cubic inches = 0.00236 m³      1 m³ ≈ 423.8 board feet
1 cubic foot = 12 board feet

Enter the nominal size you buy - a 2×4 is figured as 2 by 4, even though its actual size is 1½ × 3½ in - and add a row for each different size on your cutting list. The calculator totals the board feet, shows the volume in cubic feet or cubic metres, and, if you give it a price per board foot, the cost. For the formula behind it, see how to calculate board feet.

Worked example

This example follows the unit system you pick in the calculator above.

Ten 45 × 90 mm studs at 2.4 m, plus four 19 × 140 mm shelves at 3 m, at $6 per board foot:

  1. One stud: 0.045 × 0.090 × 2.4 = 0.00972 m³ → ×423.78 = 4.12 bd ft.
  2. Ten studs: 4.12 × 10 = 41.2 bd ft.
  3. One shelf: 0.019 × 0.140 × 3 = 0.00798 m³ → 3.38 bd ft; four shelves = 13.5 bd ft.
  4. Total: 41.2 + 13.5 = 54.7 bd ft ≈ 0.129 m³.
  5. Cost: 54.7 × $6 = $328 (add a waste allowance to order a little extra).

Board feet by common timber size

The board feet in one piece depends only on its thickness, width and length. This table lists the figure for common sizes, so you can multiply by your quantity in your head or check the calculator:

Nominal sizeLengthBoard feet (each)
1 × 48 ft2.67
1 × 68 ft4.00
1 × 88 ft5.33
2 × 48 ft5.33
2 × 410 ft6.67
2 × 68 ft8.00
2 × 88 ft10.67
2 × 1010 ft16.67
4 × 48 ft10.67

Hardwood is often sold in quarter thicknesses: 4/4 is one inch, 8/4 is two inches. Enter the thickness in inches (4/4 = 1, 5/4 = 1.25, 8/4 = 2) and the calculator handles the rest - see what 4/4, 5/4 and 8/4 mean for the full system.

How timber is sold where you are

In New Zealand, timber is sold by the lineal metre, with framing to NZS 3604. Whichever way it is priced, the board feet and the cubic-metre volume the calculator gives are the same physical amount of wood - 1 m³ is about 423.8 board feet - so you can take the figure to a yard that quotes either way.

One thing to watch is size: timber steps from the call (nominal) size down through gauged to dressed - a 100 mm call board is 94 mm gauged and 90 mm dressed. Enter the size you order at the yard in the calculator above so the volume matches what you actually buy. For the detail, see New Zealand call, gauged and dressed timber sizes.

Board feet, linear feet and cubic metres

These three measure different things, and mixing them up is the usual source of an under-order:

  • Board feet is a volume - thickness × width × length. It is how rough and hardwood timber is priced, and what you compare across sizes.
  • Linear (running) feet is just length. A board sold “by the foot” is sold by linear feet, regardless of its cross-section. A foot of 1×12 is one board foot; a foot of 1×6 is half a board foot.
  • Cubic metres is the metric volume. Timber yards outside North America price by the m³ - the calculator shows it alongside the board feet so you can order either way.

For the plain-English version, see what is a board foot.

Tips for ordering timber

  • Order to the nominal size and let the calculator add a waste allowance - rough stock, defects and cutting around knots all eat into a board.
  • For a long cutting list, add one row per size rather than averaging - a few wide, thick pieces carry far more board feet than a pile of thin ones.
  • Hardwood priced per board foot is usually rough-sawn and oversize; softwood at the home centre is sold per piece at the dressed size but still figured in nominal board feet.
  • Buy a little extra length where you can - it is cheaper to trim a long board than to splice a short one.
  • This tool sizes the quantity, volume and cost, not the structural design - take member sizes and spans from your plan or local building code.

Frequently asked questions

01

How do you calculate board feet?

A board foot is a unit of timber volume - about 0.00236 m³, or 423.8 board feet to the cubic metre. Working in metres, multiply thickness × width × length to get the volume in cubic metres, then multiply by 423.8. A 45 × 90 mm stud at 2.4 m is 0.045 × 0.090 × 2.4 = 0.00972 m³, about 4.1 board feet, so ten of them are roughly 41 board feet. The calculator adds up every size on your cutting list and shows the cubic-metre volume alongside.

02

What is a board foot?

A board foot is a unit of timber volume, not length or area. It equals about 0.00236 m³ - the volume of a board roughly 25 mm thick and 300 mm square, or any piece with the same volume. It is the unit North American mills and hardwood suppliers price by, and you will still meet it on imported and figured hardwood. One cubic metre is about 423.8 board feet.

03

Do I use nominal or actual size for board feet?

Use the nominal size - the size the timber is sold as. A 45 × 90 is figured at 45 × 90 even though dressed (DAR) timber finishes a few millimetres under, and board-foot pricing follows the nominal size. The calculator just multiplies the dimensions you enter, so type the size you order at the yard. For rough-sawn or imported hardwood, enter the sawn size before it is dressed.

04

How do I convert board feet to cubic metres?

Divide board feet by 423.776, or multiply by 0.00236. So 100 board feet is about 0.236 m³, and 1 m³ is about 423.8 board feet. The calculator shows both at once: enter your sizes and read the cubic-metre volume for a yard that sells timber by the m³, or the board feet for a supplier that quotes that way.

05

How much does timber cost per board foot?

It depends entirely on the species and grade - construction softwood is at the low end, while figured hardwoods cost many times more. Rather than guess a figure, put your own price per board foot into the calculator and it multiplies it by the board feet to order (waste included) for a total. Leave the price at zero if you only want the quantity.

06

How do I work out board feet for a whole cutting list?

Add a row for each different size. Enter the thickness, width, length and how many of that size, and the calculator works out the board feet for the row and adds every row into a total. A waste allowance bumps the figure so you order a little extra for offcuts and defects, and the volume and cost update with it.

07

Is a board foot the same as a lineal metre?

No. A lineal (or running) metre is just length - one metre of a board, whatever its cross-section. A board foot is a volume that takes thickness and width into account too. A metre of 45 × 90 timber works out to fewer board feet than a metre of 45 × 140, even though both are one lineal metre. Use lineal metres when timber is sold by length and board feet when it is sold by volume.

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