Aluminum Round Bar Weight Chart: 6061 and 7075 Pounds Per Foot
By Bilbo Baggins
A 1 inch diameter 6061 aluminum round bar weighs 0.919 pounds per foot. A 2 inch weighs 3.676, a 4 inch weighs 14.70, and a 6 inch weighs 33.08. 7075 runs about 4.6 percent heavier at every size. Below is the complete table for both alloys from 0.5 to 6 inch diameter, the formula behind it, and the one mistake that produces answers four times too large. Weight determines what you pay and how the bar ships, so it is worth having the number before you order rather than after the invoice arrives.
In Short
- →Round bar weight per foot equals pi times the radius squared, times 12, times density. Use the radius, not the diameter.
- →6061 round bar: 1 inch diameter is 0.919 lb/ft, 2 inch is 3.676 lb/ft, 4 inch is 14.70 lb/ft, 6 inch is 33.08 lb/ft.
- →7075 runs about 4.6 percent heavier at every diameter, because zinc is denser than aluminum.
- →Weight scales with the square of diameter. Doubling the diameter quadruples the weight per foot, which surprises people every time.
- →The most common error is using diameter where the formula wants radius, which gives an answer four times too large.
- →Round bar is priced and shipped by weight, so this table tells you what the invoice should say and whether the order goes parcel or freight.
6061 and 7075 Round Bar, Pounds Per Foot
Computed from pi times radius squared times 12 inches times density, using 0.0975 lb per cubic inch for 6061 and 0.102 for 7075 and 7050. 7050 matches the 7075 column.
| Diameter (in) | 6061 lb/ft | 7075 and 7050 lb/ft | 6061 lb/in |
|---|---|---|---|
| 0.500 | 0.230 | 0.240 | 0.019 |
| 0.750 | 0.517 | 0.541 | 0.043 |
| 1.000 | 0.919 | 0.961 | 0.077 |
| 1.250 | 1.436 | 1.502 | 0.120 |
| 1.500 | 2.068 | 2.163 | 0.172 |
| 2.000 | 3.676 | 3.845 | 0.306 |
| 2.500 | 5.743 | 6.008 | 0.479 |
| 3.000 | 8.270 | 8.652 | 0.689 |
| 4.000 | 14.703 | 15.381 | 1.225 |
| 5.000 | 22.973 | 24.033 | 1.914 |
| 6.000 | 33.081 | 34.608 | 2.757 |
The Formula, and the Mistake
One line of math, and one very common way to get it wrong.
Round bar weight
W = pi x (Dia / 2)^2 x L x D
= 3 inch dia 6061, 24 inches long = 3.1416 x 2.25 x 24 x 0.0975 = 16.5 lbs
- Dia
- diameter in inches
- L
- length in inches
- D
- 0.0975 for 6061, 0.102 for 7075 and 7050
Weight Scales With the Square of Diameter
This catches people out on every quote. Going up one bar size is not a small step, because the area term is squared.
| Diameter change | Weight change | 6061 lb/ft |
|---|---|---|
| 1 in | baseline | 0.919 |
| 2 in, double the diameter | 4x the weight | 3.676 |
| 3 in, triple the diameter | 9x the weight | 8.270 |
| 4 in, quadruple the diameter | 16x the weight | 14.703 |
| 6 in, six times the diameter | 36x the weight | 33.081 |
Turning Weight Into Freight
Round bar ships awkwardly because it is long, so both weight and length matter.
- Parcel carriers generally cap around 150 lbs per package and have length and girth limits that long bar exceeds quickly.
- A 12 foot stick of 3 inch 6061 is about 99 lbs, which is under the weight cap but over most length limits, so it goes freight anyway.
- Cutting the bar into shorter lengths at the supplier is frequently cheaper overall than paying oversize freight on a full stick.
- Ask for the cut before you order rather than after. Cutting to your length is standard and it usually changes the shipping mode.
Buying Round Bar Sensibly
- Order the length you need, not the stock length, unless you have a use for the remainder. You pay for the whole bar either way.
- Ask about the saw tolerance on the cut length. It varies by supplier and by diameter.
- For a part that will be turned, remember you are buying the diameter you start with, not the one you finish with. Round bar has the same buy-to-fly problem as plate.
- Check whether a drop exists in your diameter. A certified remnant is the same material at a lower price.
Round bar weight is pi times radius squared times length times density, and the whole table follows from that one line. Remember that weight goes up with the square of diameter, so a step up in size is a much bigger step in pounds and in freight than it looks. Use the radius, check the length limits before assuming parcel shipping, and ask whether a drop exists in your diameter first.
Frequently Asked Questions
How much does 1 inch aluminum round bar weigh per foot?
6061 at 1 inch diameter is 0.919 pounds per foot. 7075 and 7050 at the same diameter are 0.961 pounds per foot, about 4.6 percent heavier because of their higher zinc content.
How do you calculate aluminum round bar weight?
Multiply pi by the radius squared to get the cross-sectional area in square inches, multiply by the length in inches, then multiply by density. Use 0.0975 lb per cubic inch for 6061 and 0.102 for 7075 and 7050. Use the radius, not the diameter.
How much does a 12 foot stick of 2 inch aluminum bar weigh?
In 6061, 2 inch round bar is 3.676 pounds per foot, so a 12 foot stick is about 44 pounds. In 7075 it is 3.845 pounds per foot, or about 46 pounds for 12 feet.
Why does doubling the diameter quadruple the weight?
Weight is proportional to cross-sectional area, and the area of a circle scales with the square of the radius. Double the diameter and you double the radius, which multiplies the area, and therefore the weight per foot, by four.
Is 7075 round bar heavier than 6061?
Yes, by about 4.6 percent at any given diameter. 7075 is roughly 2.81 g/cm3 against 6061 at 2.70, because zinc is denser than aluminum. 7050 is very slightly heavier again and uses the same figures in practice.
Round bar, cut to length
Price the bar and see the weight.
Aluminum round bar cut to your length with mill certs on every order and a committed ship date before you commit.