Board Foot Calculator – Measure Lumber Volume and Cost Accurately
Board feet are the standard way to measure rough sawn lumber volume in woodworking, milling and construction. Knowing how many board feet you need makes it easier to compare prices, order materials and keep track of waste on a project.
The Board Foot Calculator on MyTimeCalculator brings the most common tasks into one place. You can compute board feet for a single board, total up multiple sizes for a full cut list, convert between board feet and cubic units and estimate lumber cost with a realistic waste factor.
How This Board Foot Calculator Works
The calculator is organized into four practical modes:
- Single board foot calculator: Quickly compute board feet, cubic inches and cubic feet for one board.
- Multiple boards and total cost: Enter up to five line items and get total board feet and estimated cost.
- Volume converter: Convert any value between board feet, cubic feet and cubic inches.
- Cost and waste factor: Estimate how much to order and what it may cost after adding a waste percentage.
Each mode uses standard lumber math so you can explain and verify the results in your shop or on the job site.
Mode 1: Single Board Foot Calculator
The single board tab is ideal when you are pricing or checking one size at a time. You provide:
- Thickness in inches
- Width in inches
- Length and its unit (feet or inches)
The calculator converts the length to inches when needed and applies the standard formula:
- Board feet = thickness (in) × width (in) × length (in) ÷ 144
It also reports the same volume in cubic inches and cubic feet so you can compare to other measurements or volume-based storage and shipping calculations.
Mode 2: Multiple Boards and Total Cost
Real projects usually involve several different board sizes and quantities. The multiple boards tab lets you enter up to five line items, each with:
- Quantity of boards
- Thickness in inches
- Width in inches
- Length and unit (feet or inches)
The calculator determines board feet per board for each line, multiplies by the quantity and then adds everything up. If you enter a price per board foot, it also estimates the total cost for the whole list and shows board feet per line so you can see which pieces drive most of the volume.
Mode 3: Volume Converter Between Board Feet and Cubic Units
If you work with both dimensional and volume-based measures, the converter tab keeps the conversion math simple. You can start from any of the three units:
- Board feet
- Cubic feet
- Cubic inches
The calculator uses these relationships:
- 1 board foot = 144 cubic inches
- 1 board foot = 1 ÷ 12 cubic feet
- 1 cubic foot = 12 board feet
It then returns equivalent values in all three units with your chosen decimal precision.
Mode 4: Lumber Cost with Waste Factor
Every woodworker and contractor knows that a project usually uses more lumber than the net board footage in the final piece. Knots, checks, cracks, tear-out and layout choices create offcuts and unusable sections.
In the cost and waste tab, you enter:
- Net board feet the project is expected to use
- Price per board foot from your supplier
- Waste factor as a percentage
The calculator estimates base cost for the net requirement, then increases board feet and cost by the waste factor. It reports:
- Base material cost without waste
- Extra board feet to cover waste
- Total board feet to order
- Total cost including waste
This helps you budget more realistically and reduces the risk of running short partway through the job.
Understanding Board Foot Math in Practice
Board foot calculations rely on nominal dimensions, which may differ from the actual finished size of planed lumber. Many yards and price lists are still based on nominal thickness and width. Some practical tips include:
- Check whether your supplier uses nominal or actual dimensions for billing.
- Remember that surfacing and planing can reduce thickness and width, even though pricing may still use the rough size.
- For narrow glue-ups, you can total the board feet of the rough boards rather than each individual strip.
- For heavy timber or beams, volume differences between nominal and actual sizes can be more significant.
Using a calculator helps avoid mental arithmetic mistakes when orders are large or involve several different dimensions.
How to Use This Calculator Effectively
- Start with the single board tab to confirm that you understand the formula and units.
- Prepare a cut list for your project and use the multiple boards tab to estimate total board feet and cost.
- Experiment with different waste factors based on wood species, project complexity and your own experience level.
- Use the converter tab whenever you see volume expressed in cubic units and need to relate it to board feet pricing.
- Round up slightly or add your own safety margin for critical projects where extra material is safer than coming up short.
This Board Foot Calculator is intended as a planning tool. Actual yields and costs depend on the lumber you buy, how you break it down and real-world shop conditions.
Board Foot FAQs
Frequently Asked Questions About Board Feet
Short answers to help you interpret board foot calculations when planning lumber purchases.
Board feet measure the volume of lumber, which allows suppliers to price boards of different dimensions on a consistent basis. Two boards with different thickness and width but the same board footage represent the same volume of wood and are often priced similarly per board foot.
Most pricing is based on nominal rough-sawn dimensions, even if the boards are planed to a slightly smaller actual size. If you are estimating cost, it is usually best to use the nominal size used by your supplier. If you are calculating net project volume, you may prefer to use actual finished dimensions.
The calculator assumes thickness and width in inches and length in either inches or feet. For metric dimensions, you can convert millimeters or centimeters to inches first and then enter the converted values. Some woodworkers keep a small conversion chart or tool handy for this purpose.
Typical waste factors range from about 5% for simple projects in clear stock to 15% or more for knotty lumber, complex joinery or projects with many short parts. If you are unsure, it can be helpful to start with a moderate value, such as 10%, and adjust as you gain experience with similar projects and species.
No. For large jobs, structural work or projects that must follow building codes, a detailed material takeoff by a qualified professional is important. This calculator is a quick planning and education tool that helps you understand the numbers and cross-check estimates.