Created by Bogna Szyk

Reviewed by

Małgorzata Koperska, MD and Jack Bowater

Last updated:

Jan 18, 2024

- What is a board foot?
- How to calculate board feet?
- Using the lumber calculator: an example
- FAQ

This board foot calculator allows you to quickly **estimate the volume of hardwood lumber** you want to buy. If you're unsure how to calculate board feet or what a board foot is, scroll down for more in-depth information. Otherwise, simply type the dimensions of a wood piece into this board foot calculator!

Unlike square footage, which measures area, board footage measures **volume**. You use it when purchasing multiple boards of lumber in various sizes.

By definition, one board foot of lumber is **one square foot that is one-inch thick**. If you would like to convert regular volume units into board feet, use the following relation:

`1 board foot = 144 cubic inches = 1/12 cubic foot`

## How to calculate board feet?

Surprisingly, the calculations are extremely easy! All you need to do is use the board foot formula below:

`board feet = length (ft) × width (in) × thickness (in) / 12`

Pay special attention to the units! The length of the wooden board should be expressed in feet, while the width and thickness – in inches.

💡 You might also be interested in our flooring calculator and decking calculator.

## Using the lumber calculator: an example

Let's assume you want to use this board foot calculator to determine how much you should pay for a few hardwood pieces.

Decide on the

**number of pieces**you want to purchase. Let's assume it's five wooden boards.Choose the

**dimensions of the boards**. For example, a piece of hardwood can be 8 feet long, 10 inches wide, and 1.25 inches thick.Substitute these numbers into the

**board foot formula**to find the board footage per piece:`board feet = length(ft) × width(in) × thickness(in) / 12`

`board feet = 8 × 10 × 1.25 / 12`

`board feet = 8.33 BF`

Now,

**multiply this result by the number of pieces**to obtain the total board footage of your purchase:`5 × 8.33 = 41.67 BF`

Finally, you can

**multiply this value by the price per board foot**to determine the total cost of your purchase. Assuming one board foot of lumber costs $4.15, then:`cost = 41.67 × $4.15 = $172.92`

💡 If you need to cover walls or flooring in plywood, check out our plywood calculator.

## FAQ

### How do you calculate the board feet in a log?

To calculate the board feet in a log, do the following:

Find either a

**Doyle rule**or the**International ¼-inch rule table**.Measure the diameter of the

**shorter end of the log**(not including bark) in inches.Measure the length of the log in feet.

Look up where the two values meet on the table.

Alternatively, use the equation

**((Diameter - 4)/4)² × Length**, where the units are those you measured.The answer is an estimate of the board feet in a log.

### How do you measure a board foot?

To measure a board foot:

Take a rectangular piece of lumber.

Measure the length of it

**in feet**, rounding to the nearest decimal place.Measure the width

**in inches**. You can also measure in feet; if so, don’t divide by 12 in step 5.Measure the thickness

**in inches**.**Multiply**all three numbers together and**divide**by 12.

### How many board feet are in a 2x4?

Length of 2x4 (ft) | Number of board feet |
---|---|

6 | 4 |

8 | 51/3 |

10 | 62/3 |

12 | 8 |

14 | 91/3 |

16 | 102/3 |

18 | 12 |

20 | 131/3 |

22 | 142/3 |

24 | 16 |

### What is the difference between a board foot and a linear foot?

The main difference between a board foot and a linear foot is that **a board foot is a measure of volume**, whereas **a linear foot is a measure of length**.

A board foot is generally used for lumber and is the multiplication of its width in feet, length in feet, and thickness in inches. A linear foot is a straight line 12 inches (1 foot) in length.

### What is a board foot insulation?

Board foot insulation is a measurement of **how much volume spray foam insulation can cover**.

A board foot is a volume of 1 ft × 1 ft × 1 in, so estimate the volume you need to fill before buying your spray foam insulation by finding the square footage of the space.

A board foot is also a common unit of measure for lumber in the USA and Canada.

### How much does a board foot of oak weigh?

A board foot of oak weighs **anywhere between 3.08-4.67 lb (1.42-2.12 kg)**, but **on average, one weighs 3.875 lb (1.77 kg)**.

That is because the density of Oak can vary from 37-56 lb/ft³ (600-900 kg/m³), depending on the variety and location it was grown.

### How many board feet are there in 320 square feet?

There are **no board feet in 320 square feet**, as board feet is **a measure of volume** and square feet is a measure of area. However, for an area that is 320 square feet with a depth of 1 inch, there are 320 board feet present.

Bogna Szyk

## Related calculators

- Stone Weight Calculator
- Board and Batten Calculator