Board Foot Calculator
Work out lumber the way yards sell it with this board foot calculator. Pick a standard size or type your own, and read the full tally in one result. The tool shows board feet to buy with waste added, the nominal count and the actual wood count side by side, the linear feet, and the cost at your price per board foot. It suits framing studs, deck boards and fine hardwood planks alike.
What the result numbers mean
The order number. It is your full tally plus the waste for your wood type, so milling and defects stay covered.
One board counted at its shelf name size. A 2x4 that runs 8 feet reads 5.33 board feet on this tally.
Per board times your board count, before waste. This is the number a per board foot price multiplies.
The same boards at their dressed size. A 2x4 is really 1.5 by 3.5 inches, so the real wood reads 3.50 board feet.
The plain length of your boards added up. Trim, transport and storage plans read this line.
Add a price per board foot and the tool prices the buy tally. Yards quote this unit, so the math matches the counter.
How do I calculate board feet?
Multiply the thickness in inches by the width in inches by the length in feet. Divide by 12. A 2x4 that runs 8 feet holds 5.33 board feet on the nominal tally, and 3.5 board feet of real wood at its actual size.
How the math works
Choose a standard shelf size or type a custom one. The size goes in at its nominal name, the way the shelf labels it.
Multiply thickness by width by length in feet, then divide by 12. That is the board foot rule every yard uses.
T x W x L / 12Boards dress down smaller than the name. The tool reads the standard dressed size and shows the real wood count beside the nominal one.
Multiply the per board tally by your board count. A cut list of many parts runs part by part, then adds up.
The wood type sets the waste. Softwood needs 10 percent. Domestic hardwood needs 15. Exotic wood needs 20.
Softwood 10, Hardwood 15, Exotic 20Add the yard price per board foot and the order prices out. Compare woods in this unit and the cheap board shows its true cost.
A 2 by 4 stud, 8 feet long
Here is the stud from the quick answer, on a breakdown slip, the way the tool builds it.
Read the slip top to bottom. The nominal tally is the shelf math, and yards price by it. The actual line is the wood you really take home. The waste line covers the milling and the one bad board in the stack.
Common lumber sizes, explained
This board foot calculator knows the dressed size behind every shelf name. Tap a size card to load that board in the tool at 8 feet long.
Trim, battens and light craft boards. The true size is 0.75 by 3.5 inches, so each foot holds 0.33 board feet at the name size.
Key measure: 0.33 bf per footTap to load in the calculatorShelves, boxes and wide trim. True size 0.75 by 5.5 inches. Each foot holds 0.50 board feet at the name size.
Key measure: 0.50 bf per footTap to load in the calculatorTabletops, stair treads and fine planks. True size 0.75 by 7.25 inches. Each foot holds 0.67 board feet at the name size.
Key measure: 0.67 bf per footTap to load in the calculatorThe framing stud of house building. True size 1.5 by 3.5 inches. The 8 foot stud is the most counted board in the trade.
Key measure: 0.67 bf per footTap to load in the calculatorDeck boards, joists and strong frames. True size 1.5 by 5.5 inches. Each foot holds a full 1.00 board foot at the name size.
Key measure: 1.00 bf per footTap to load in the calculatorStair stringers, headers and heavy beams. True size 1.5 by 11.25 inches. Each foot holds 2.00 board feet at the name size.
Key measure: 2.00 bf per footTap to load in the calculatorWhat the pile weighs
Weight decides the truck, the trailer and the carry plan. Multiply your board feet by the species figure in the weight table below, with the other lumber numbers.
One hundred board feet of oak runs near 390 pounds. The same stack in cedar runs near 230 pounds. Check the payload sticker on the truck before a long hardwood haul.
Unit conversions, in plain rules
Convert cubic feet to board feet by multiplying by 12. One cubic foot holds 12 board feet of wood.
Convert board feet to square feet by dividing by the thickness in inches. At 1 inch thick the two numbers match, so 320 square feet of 1 inch boards holds 320 board feet.
Convert square feet back to board feet by multiplying by the thickness in inches. Convert board feet to cubic meters by dividing by 424, since 1,000 board feet runs about 2.36 cubic meters.
Lumber numbers, in one place
| Nominal size | Actual size | BF per foot, nominal | BF per foot, actual |
|---|---|---|---|
| 1 x 4 | 0.75 x 3.5 in | 0.33 | 0.22 |
| 1 x 6 | 0.75 x 5.5 in | 0.50 | 0.34 |
| 2 x 4 | 1.5 x 3.5 in | 0.67 | 0.44 |
| 2 x 6 | 1.5 x 5.5 in | 1.00 | 0.69 |
| 2 x 8 | 1.5 x 7.25 in | 1.33 | 0.91 |
| 2 x 10 | 1.5 x 9.25 in | 1.67 | 1.16 |
| 2 x 12 | 1.5 x 11.25 in | 2.00 | 1.41 |
Common mistakes
One list with both tallies means nothing. Pick the nominal tally for price and the actual tally for fit, and never blend them.
The formula wants the length in feet. A length typed in inches blows the count up twelve times too big.
Milling eats rough boards before the project starts. The waste percent by wood type exists for that first pass at the planer.
Boards differ in size, so a per board price hides the truth. Per board foot is the only fair compare, and the tool prices it.
How to buy lumber with your tally
The result moment is the buying moment. Use the board foot tally from this board foot calculator at the yard counter. Two routes cover most lumber buys.
Option A: Dimensional lumber at the store
- The shelf sells by the board. Turn the price into a per board foot cost before you compare piles.
- Check the true size on the label. A 2x4 is 1.5 by 3.5 inches of real wood.
- Sight down each board for bow and twist. One bad stud costs more time than money.
- Buy the full cut list in one trip, so the stack matches in tone and moisture.
Option B: Rough lumber at the yard
- The yard prices by the board foot. Your buy tally is the order number.
- Rough boards need milling, so the waste percent matters more here.
- Ask about grade. Clear boards cost more per foot and waste less.
- Long boards price better per foot at many yards. Ask before you cut the list down.
For the floor or the deck frame these boards land on, the flooring calculator counts boxes in the same style. For the concrete piers under a deck, the concrete calculator gives yards and bags from one measure.
Questions, answered
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