Lumber Size Converter

Convert common nominal lumber sizes to actual dimensions, compare inches and metric sizes, and estimate board feet from board length and quantity.

Convert Lumber Size

2 × 4 nominal lumber = 1.5 in × 3.5 in actual
Your lumber size result will appear here.

Common lumber size conversions

2 × 4 actual size:
1.5 in × 3.5 in

2 × 6 actual size:
1.5 in × 5.5 in

2 × 8 actual size:
1.5 in × 7.25 in

4 × 4 actual size:
3.5 in × 3.5 in

Where lumber size conversions are used

Lumber size conversions are useful for framing, decks, sheds, posts, blocking, trim work, woodworking, rough material planning, and construction estimates.

Use this converter when comparing nominal board names, actual board dimensions, metric measurements, and board foot estimates.

What your lumber size result means

Your result shows the actual lumber thickness and width for the selected nominal size. It also shows the board length, quantity, estimated board feet, and metric dimensions.

For material estimating, remember that actual lumber dimensions can vary slightly by product, manufacturer, moisture content, and surfaced or rough-sawn condition.

Lumber size converter tips

Frequently asked questions

Why is a 2 × 4 not actually 2 inches by 4 inches?

A 2 × 4 is a nominal size. After drying and surfacing, the finished board is usually about 1.5 inches by 3.5 inches.

What is the actual size of a 2 × 6?

A standard 2 × 6 is usually 1.5 inches thick by 5.5 inches wide.

What is the actual size of a 4 × 4?

A standard 4 × 4 is usually 3.5 inches by 3.5 inches.

How are board feet calculated?

Board feet are calculated as thickness in inches multiplied by width in inches multiplied by length in feet, divided by 12.

Is this the same as a board feet converter?

No. This converter focuses on nominal and actual lumber size. A board feet converter focuses mainly on lumber volume unit conversions.