Nominal Vs Actual Lumber Sizes Chart [Lumber Sizes]
Nominal lumber sizes are the dimensions of a board as specified by the manufacturer. They are different from actual lumber sizes because nominal lumber dimensions may be slightly off from the actual dimensions of a board due to many factors, such as manufacturing tolerances and scrap.
Nominal lumber sizes allow for easy comparison between boards, but they don’t give you an accurate measurement of the size of a board or its thickness.
This chart depicts the difference between nominal and actual lumber sizes. It is a guide to help you identify the dimensions of lumber, plan your lumber cuts and construction needs.
Dimensional Lumber Sizes: Nominal vs. Actual
1X Board Lumber Sizes Chart
| NOMINAL SIZE (INCHES) | ACTUAL SIZE (INCHES) | ACTUAL SIZE (MM) |
| 1×2 | 3/4 X 1 1/2 | 19 X 38 |
| 1×3 | 3/4 X 2 1/2 | 19 X 64 |
| 1×4 | 3/4 X 3 1/2 | 19 X 89 |
| 1×6 | 3/4 X 5 1/2 | 19 X 140 |
| 1×8 | 3/4 X 7 1/4 | 19 X 184 |
| 1×10 | 3/4 X 9 1/4 | 19 X 235 |
| 1×12 | 3/4 X 11 1/4 | 19 X 286 |
2X Board Lumber Sizes Chart
| NOMINAL SIZE (INCHES) | ACTUAL SIZE (INCHES) | ACTUAL SIZE (MM) |
| 2×2 | 1 1/2 x 1 1/2 | 38 X 38 |
| 2×3 | 1 1/2 x 2 1/2 | 38 X 64 |
| 2×4 | 1 1/2 x 3 1/2 | 38 X 89 |
| 2×6 | 1 1/2 x 5 1/2 | 38 X 140 |
| 2×8 | 1 1/2 x 7 1/4 | 38 X 184 |
| 2×10 | 1 1/2 x 9 1/4 | 38 X 235 |
| 2×12 | 1 1/2 x 11 1/4 | 38 X 286 |
3X Board Lumber Sizes Chart
| NOMINAL SIZE (INCHES) | ACTUAL SIZE (INCHES) | ACTUAL SIZE (MM) |
| 3×3 | 2 1/2 x 2 1/2 | 64 X 64 |
| 3×4 | 2 1/2 x 3 1/2 | 64 X 89 |
| 3×6 | 2 1/2 x 5 1/2 | 64 X 140 |
| 3×8 | 2 1/2 x 7 1/4 | 64 X 184 |
| 3×10 | 2 1/2 x 9 1/4 | 64 X 235 |
| 3×12 | 2 1/2 x 11 1/4 | 64 X 286 |
4X Board Lumber Sizes Chart
| NOMINAL SIZE (INCHES) | ACTUAL SIZE (INCHES) | ACTUAL SIZE (MM) |
| 4×4 | 3 1/2 x 3 1/2 | 89 X 89 |
| 4×6 | 3 1/2 x 5 1/2 | 89 X 140 |
| 4×8 | 3 1/2 x 7 1/4 | 89 X 184 |
| 4×10 | 3 1/2 x 9 1/4 | 89 X 235 |
| 4×12 | 3 1/2 x 11 1/4 | 89 X 286 |
6X Board Lumber Sizes Chart
| NOMINAL SIZE (INCHES) | ACTUAL SIZE (INCHES) | ACTUAL SIZE (MM) |
| 6×6 | 5 1/2 x 5 1/2 | 140 x 140 |
8X Board Lumber Sizes Chart
| NOMINAL SIZE (INCHES) | ACTUAL SIZE (INCHES) | ACTUAL SIZE (MM) |
| 8×8 | 7 1/4 x 7 1/4 | 184 x 184 |
Softwood Lumber Lengths Chart
| LENGTH IN FEET | LENGTH IN INCHES | LENGTH IN METERS |
| 6 feet | 72 inches | 1.829 meters |
| 8 feet | 96 inches | 2.438 meters |
| 10 feet | 120 inches | 3.048 meters |
| 12 feet | 144 inches | 3.658 meters |
| 14 feet | 168 inches | 4.267 meters |
| 16 feet | 192 inches | 4.877 meters |
| 18 feet | 216 inches | 5.486 meters |
| 20 feet | 240 inches | 6.096 meters |
| 22 feet | 264 inches | 6.706 meters |
| 24 feet | 288 inches | 7.315 meters |
Hardwood Lumber Dimensions Chart
| NOMINAL SIZE | ROUGH SIZE | ACTUAL SIZE: SURFACED 1 SIDE | ACTUAL SIZE: SURFACED 2 SIDES |
| – | 1/2 inch | 3/8 inch (9.5 mm) | 5/16 inch (7.9 mm) |
| – | 5/8 inch | 1/2 inch (13 mm) | 7/16 inch (11 mm) |
| – | 3/4 inch | 5/8 inch (16 mm) | 9/16 inch (14 mm) |
| 4/4 inch | 1 inch | 7/8 inch (22 mm) | 13/16 inch (21 mm) |
| 5/4 inch | 1 1/4 inch | 1 1/8 inch (29 mm) | 1 1/16 inch (27 mm) |
| 6/4 inch | 1 1/2 inch | 1 3/8 inch (35 mm) | 1 5/16 inch (33 mm) |
| 8/4 inch | 2 inches | 1 13/16 inch (46 mm) | 1 3/4 inch (44 mm) |
| 12/4 inch | 3 inches | 2 13/16 inch (71 mm) | 2 3/4 inch (70 mm) |
| 16/4 inch | 4 inches | 3 13/16 inch (97 mm) | 3 3/4 inch (95 mm) |
Glue Laminated Lumber Dimensions Chart
| NOMINAL WIDTH | ACTUAL FINISHED WIDTH |
| 3″ | 2 1/2″ |
| 4″ | 3 1/8″ or 3 1/2″ |
| 6″ | 5 1/8″ or 5 1/2″ |
| 8″ | 6 3/4″ |
| 10″ | 8 3/4″ |
| 12″ | 10 3/4″ |
| 14″ | 12 1/4″ |
| 16″ | 14 1/4″ |
Which lumber size chart is better: nominal or actual?
Check out my 24 years of Woodworking database HERE
The nominal size chart is used when determining lumber dimensions in millimeters and inches. The actual size chart, on the other hand, is a measurement that takes into account the thickness of the lumber, so it will be more accurate than nominal measurements.
If you are looking for something that is in between these two charts, then go with the inch equivalent of nominal dimensions or a combination of both.
What is the difference between nominal and actual lumber sizes?
The nominal size is the actual size of a piece of lumber. It is also known as standard or trade sizes.
The actual size is the actual width, height, and thickness of a piece of lumber.
Why do I need to know which one to use when purchasing lumber?
The type of lumber you purchase will depend on what you want to use it for.
You should always consider the end-use and the quality that is needed for your project before purchasing lumber. If you are unsure, contact a local lumber dealer or woodworker to help you decide which type of lumber would be best for your project.
Why is a 2×4 not actually 2×4?
A 2×4 is actually 1.5 inches by 3.5 inches, so it’s a half-inch thick.
A 2×4 is not actually 2×4 because a “2” and a “4” are next to each other on the board (1+1=2).
How much smaller is nominal size lumber than actual size lumber?
Nominal size lumber is the size of a piece of lumber that is measured in inches. Actual size lumber is the actual measurements of a piece of lumber, not including any thickness or width.
Nominal Size Lumber: nominal size lumber is usually 2×4 or 2×6 and has an actual measurement of 3/4 inch by 4 1/2 inches (the height does not include the thickness).
Actual Size Lumber: actual size lumber has an actual measurement of 1-1/2 inch by 6 inches.
What does 1×4 wood mean?
1X Board Lumber Sizes:
Two boards size 1×4 and 1×6 lose their thickness and width consequently 1/4 and 1/2 inch.
It means the 1×4 actual lumber size is 3/4 inches thickness and 3-1/2 inches width.
2X Board Lumber Sizes:
Two boards size 2×4 and 2×6 lose their thickness and width consequently 1/2 inch and 1/2 inch.
It means the 2×4 actual lumber size is 1-1/2 inches thickness and 3-1/2 inches width.
How much smaller is nominal size lumber than actual size lumber?
Nominal size lumber is the size of a piece of lumber that has been cut and branded for sale which is 1/4 inches smaller than the actual size lumber.
Actual size lumber is the actual width, height, and thickness of a piece of lumber.
What are the actual dimensions of a 2×6 piece of lumber?
It means a 2 x 6 board is actually 1-1/2 inches by 3-1/2 inches.
Conclusion
This chart provides a clear picture of the differences between nominal and actual lumber sizes.
The chart shows the difference between nominal and actual lumber sizes for dimensioned lumber, rough sawn lumber, dimensioned rough sawn lumber, rough sawn dimensions, square stock dimensions, round stock dimensions, quarter-sawn dimensions, and kiln-dried.
It is very important to know the actual size of the lumber. If you are a DIY enthusiast, then you must have known about the nominal vs actual lumber sizes chart.
