Carpenter Calculator: Board Feet, Waste and Cost

How do you figure board feet?

The carpenter calculator uses this formula: thickness times width times length, divided by 12, times pieces. Thickness and width are inches. Length is feet. One board foot equals a board 1 inch thick, 12 inches wide, and 1 foot long.

For example, ten boards at 1 inch by 6 inches by 8 feet equal 40 board feet. Those sizes are only an example. For wall counts, use the framing stud calculator.

Once you have the quantities, try SimplyWise Cost Estimator free to build your quote.

How do you add waste?

Multiply net board feet by one plus waste percent divided by 100. For example, 40 board feet with a chosen 10% allowance becomes 44 board feet. That example does not set a waste rule for your job.

First, lay out the cuts. Then allow for knots, end cuts, and grain matching. Board feet alone cannot tell you which stock lengths to buy. For sheet goods, use the plywood calculator instead.

Use the carpenter calculator, step by step

1. Measure one board

   First, enter thickness and width in inches. Then enter length in feet. Use the sizes your supplier uses to bill.

2. Count matching pieces

   Next, group boards that share those dimensions. Run each group on its own. Then add the group totals.

3. Add your waste allowance

   Allow for cut ends, saw cuts, and defects. A careful cut list helps you choose the extra wood you need.

4. Price the wood and time

   Finally, enter the quoted board-foot price and total labor hours. Use your own hourly rate for the labor line.

How do you convert fractions?

Divide the top number by the bottom number. So 3/4 becomes 0.75. For a mixed number, add the whole part: 1 1/2 becomes 1.5. The inch fields accept either form.

The converter keeps up to six decimal places. Board feet display to two places, but material math uses the full value. For stair layout, use the stair stringer calculator.

What should the materials and labor lines include?

Materials equal board feet with waste times your price per board foot. Labor equals total hours times your rate. Each cost line rounds to cents. The subtotal adds those rounded lines.

BLS OEWS, May 2025 lists a national median carpenter wage of $29.12 an hour. In a worked example, 4 hours times $29.12 equals $116.48 in wages before payroll costs. This is an employee wage, not a customer billing rate.

Use the labor cost calculator to work through payroll costs. Then add delivery, fasteners, tax, overhead, and profit to your quote. This carpenter calculator does not add them.

Check the inputs before you quote

Confirm whether the supplier bills on rough or finished sizes. Match the price basis to those dimensions. Also check species, grade, stock length, and delivery terms.

For repairs, check whether sound wood can stay. Replace damaged parts as the scope requires. For roof cuts, use the roof pitch calculator to check the slope.

Match the order to the cut list

List each finished part and its length before buying. Then check how those parts fit the boards on the rack. A volume total can look right while the boards are too short. Keep separate groups for each size. If the yard sells by piece or linear foot, ask for that price basis before using a board-foot rate.

Turn your quantities into a SimplyWise quote

SimplyWise Cost Estimator turns a photo into an itemized estimate in about 6 seconds. Review each material and labor line. Then send a professional, branded quote the client signs to approve.

Try SimplyWise Cost Estimator free after you check the carpenter calculator results.

Keep reading

• Construction calculators: choose a takeoff tool.
• How to estimate framing: plan the full scope.
• Markup vs margin: build your selling price.