Aluminum Plate Weight Chart: 6061, 7075, and 7050 Pounds Per Square Foot and Per Full Plate

The Density Numbers You Need

Everything starts with density. 6061 is a magnesium-silicon alloy and is the lightest of the three. 7075 and 7050 both carry substantial zinc, which is denser than aluminum, so they weigh more for identical dimensions. The industry convention is to treat both 7xxx alloys as 0.102 lb/in3, and the tables below follow that convention.

The Formula

For a rectangular plate, weight is just volume times density. Work in inches and pounds and it comes out clean: weight in lbs = thickness x width x length x density. A 24 x 48 x 1 inch piece of 6061 is 1 x 24 x 48 x 0.0975, which is 112.3 lbs. The same piece in 7075 is 1 x 24 x 48 x 0.102, or 117.5 lbs. If you prefer to think in square feet, multiply the density by 144 to get pounds per square foot per inch of thickness, then multiply by your actual thickness and area.

• By dimensions: lbs = thickness (in) x width (in) x length (in) x density (lb/in3)
• By area: lbs = area (sq ft) x 144 x thickness (in) x density (lb/in3)
• 6061 shortcut: lbs per sq ft = 14.04 x thickness in inches
• 7075 and 7050 shortcut: lbs per sq ft = 14.69 x thickness in inches
• Metric: kg = thickness (mm) x width (mm) x length (mm) x density (g/cm3) / 1,000,000

Weight Per Square Foot by Thickness

This is the table most people are actually looking for. Find your thickness, read across, and multiply by your square footage. Values are pounds per square foot.

Full Mill Plate Weights

Mills produce plate in master sizes, typically 48.5 x 144.5 inches and 60.5 x 144.5 inches, with 48.5 x 96.5 also common. If you are buying full plate, these are the weights that land on your dock and on your freight bill. Values are pounds per plate for 6061, with 7075 and 7050 in parentheses.

Common Cut Sizes at a Glance

Most orders are not full plate. These are the weights for frequently ordered rectangles at 1 inch thick. For any other thickness, scale linearly: a 0.5 inch piece is exactly half, a 2 inch piece is exactly double.

The 4.6% Nobody Budgets For

Because 7075 and 7050 are denser than 6061, an alloy substitution is also a weight change. Swapping 6061 for 7075 on identical dimensions adds 4.6% to the weight, which means 4.6% more billed pounds on top of the alloy premium, and 4.6% more mass in the finished assembly. On a single 60.5 x 144.5 x 2 inch plate that is roughly 78 lbs. Across a production run it is real money and, on a weight-critical design, real performance. Conversely, if you are substituting toward 6061 for cost reasons, you get a small weight reduction as a bonus.

Weight Is How You Get Billed

Aluminum plate is sold by the pound, so the weight calculation and the invoice are tied directly together. This is why it is worth calculating the weight yourself before you order: it tells you what you should be billed for, it tells you your freight class, and it lets you check a quote by dividing the quoted total by the weight you calculated. If the billed weight on the invoice is meaningfully higher than the plate you actually received, that is usually a minimum-billed-weight clause rather than an error, and it is worth asking about before you order rather than after.

• Ask for the billed weight, not just the rate. Two quotes can look identical per pound and land very differently once minimums apply.
• Confirm whether the supplier invoices theoretical calculated weight or actual scale weight. On a large order the difference is not trivial.
• Check the billed weight against your own calculation from the dimensions you ordered.
• Remember that mill plate is nominally oversized, so a plate sold as 48 x 144 is typically 48.5 x 144.5 and weighs about 1.4% more than the nominal figure.

Do Not Forget Buy-to-Fly

The weight you purchase and the weight you keep are different numbers, and the gap is bigger than most people expect. Machining a part out of plate means paying for material that becomes chips. In general fabrication, buy-to-fly ratios of 2:1 to 4:1 are typical. In aerospace, where parts are machined from thick plate with deep pockets, 5:1 to 15:1 is normal and complex bulkheads can exceed 20:1. If your finished part weighs 40 lbs and your buy-to-fly is 8:1, you are purchasing 320 lbs of plate. Budget the purchased weight, not the finished weight.

Where Calculated Weight and Actual Weight Diverge

Your calculation will rarely match the scale exactly, and that is normal. A few reasons why, worth knowing before you dispute an invoice.

• Thickness tolerance. Plate is produced to a tolerance band, not an exact gauge. A nominal 1 inch plate may measure 0.990 to 1.020, which moves the weight by 1 to 2%.
• Nominal versus actual dimensions. Mill plate is oversized. A plate sold as 48 x 144 is usually 48.5 x 144.5, which is about 1.4% more area than nominal.
• Density is a nominal figure. Actual alloy chemistry varies within spec, so real density varies slightly lot to lot.
• Saw kerf. Every cut removes material. Our bandsaws run a 0.08 inch kerf, so a piece cut from a larger plate loses that width of metal per cut.
• Theoretical versus scale weight. Some suppliers bill theoretical calculated weight and some bill actual scale weight. Ask which, because on a large order the difference is not trivial.