Use this free round bar weight calculator to estimate the weight of steel, stainless steel, aluminum, brass, copper, and other solid metal round bars. Enter the diameter, length, material, and quantity to get weight per bar, weight per meter, weight per foot, and total project weight. The formulas, density tables, and charts below help you verify the calculation manually.
Select the metal type, enter the diameter and length, and calculate the estimated round bar weight in kilograms, pounds, and metric tonnes.
Note: The results below are theoretical weights based on standard material density and nominal dimensions. Actual supplier weight may vary due to manufacturing tolerance, material grade, surface finish, and cutting length.
Table of Contents
How to calculate round bar weight
Round bar weight depends on three main inputs:
- Diameter (measured across the widest part of the bar).
- Length (the full length of the bar).
- Material density (steel, stainless steel, aluminum, brass, and copper all have different densities).
The calculator does the math automatically. Understanding the basic formula helps you check the result and compare materials.
For the most accurate estimate, use the actual measured diameter if possible. Use the exact cut length, select the correct material grade, and enter the number of bars if you need the total project weight. You should also confirm the final weight with your supplier for shipping, engineering, or procurement.
Round bar weight formula
The basic formula for round bar weight is:
Weight = Volume x Density
Because a round bar is a solid cylinder, the volume is:
Volume = π x radius² x length
So the full formula becomes:
Weight = π x radius² x length x density
Where:
- π = 3.14159
- Radius = diameter / 2
- Length = bar length
- Density = material density
For quick mild steel estimates, you can use simplified formulas.
Metric formula for mild steel
Weight (kg/m) = Diameter (mm) x Diameter (mm) x 0.006162
Example: A 20 mm mild steel round bar.
20 x 20 x 0.006162 = 2.465 kg/m.
A 20 mm mild steel round bar weighs about 2.47 kg per meter.
Imperial formula for mild steel
Weight (lbs/ft) = Diameter (inches) x Diameter (inches) x 2.67
Example: A 1-inch mild steel round bar.
1 x 1 x 2.67 = 2.67 lbs/ft.
A 1-inch mild steel round bar weighs about 2.67 pounds per foot.
Quick formula reference
| Material | Metric Formula | Imperial Formula |
|---|---|---|
| Mild Steel | kg/m = D² x 0.006162 | lbs/ft = D² x 2.67 |
| Stainless Steel | kg/m = D² x 0.00620 to 0.00628 | lbs/ft = D² x 2.72 |
| Aluminum | kg/m = D² x 0.00212 | lbs/ft = D² x 0.92 |
| Brass | kg/m = D² x 0.00668 | lbs/ft = D² x 2.90 |
| Copper | kg/m = D² x 0.00704 | lbs/ft = D² x 3.03 |
These formulas assume solid round bars with nominal diameter.
Round bar weight per meter
Weight per meter tells you how much a 1-meter length of round bar weighs. This is one of the most common ways to estimate metal bar weight in metric regions.
For mild steel:
kg/m = Diameter (mm) x Diameter (mm) x 0.006162
Common mild steel round bar weights per meter:
| Diameter | Weight per Meter |
|---|---|
| 10 mm | 0.62 kg/m |
| 12 mm | 0.89 kg/m |
| 16 mm | 1.58 kg/m |
| 20 mm | 2.47 kg/m |
| 25 mm | 3.85 kg/m |
| 30 mm | 5.55 kg/m |
| 32 mm | 6.31 kg/m |
| 40 mm | 9.86 kg/m |
| 50 mm | 15.41 kg/m |
Weight per meter is useful when you need to estimate material cost, shipping weight, fabrication weight, structural load, or total order weight.
Converting volume to weight
To convert the volume of a round bar into weight, multiply the volume by the material density.
Step 1: Calculate the radius (Radius = Diameter / 2).
Step 2: Calculate the volume (Volume = π x radius² x length).
Step 3: Multiply by density (Weight = Volume x Density).
Step 4: Convert units if needed.
Useful unit conversions:
| Conversion | Value |
|---|---|
| 1 inch | 25.4 mm |
| 1 meter | 3.28084 feet |
| 1 kilogram | 2.20462 pounds |
| 1 meter | 1,000 mm |
For manual calculations, make sure all units match. If density is in kg/m³, convert diameter and length into meters before calculating volume. The calculator on this page handles these conversions automatically, which reduces calculation errors.
Round bar density by material
Material density is the main reason round bars of the same size can weigh differently. Steel, stainless steel, aluminum, brass, and copper all have different densities.
Approximate material densities:
| Material | Density |
|---|---|
| Mild Steel | 7,850 kg/m³ |
| Stainless Steel | 7,900 to 8,000 kg/m³ |
| Aluminum | 2,700 kg/m³ |
| Brass | 8,400 to 8,700 kg/m³ |
| Copper | 8,900 to 8,960 kg/m³ |
Selecting the correct material is important for accurate weight calculation.
Mild steel round bar
Mild steel and standard carbon steel round bars are widely used in fabrication, construction, machining, and general engineering.
Approximate density: 7,850 kg/m³.
Mild steel round bars are commonly used for shafts, pins, supports, brackets, dowels, structural components, and machine parts.
For mild steel, the common metric shortcut is:
kg/m = Diameter (mm) x Diameter (mm) x 0.006162
Mild steel is heavier than aluminum but usually more affordable than stainless steel.
Stainless steel round bar
When working with corrosion-resistant stainless steel round bars, the material is chosen where hygiene, strength, or environmental resistance is important.
Approximate density: 7,900 to 8,000 kg/m³.
Common stainless steel grades include 304, 316, 416, and 17-4.
Stainless steel round bars are often used in food equipment, marine applications, medical equipment, chemical processing, architectural metalwork, and precision machining.
Because stainless steel is slightly denser than mild steel, the same size bar may weigh slightly more.
Aluminum round bar
Aluminum round bar is much lighter than steel and is commonly used when weight savings are important.
Approximate density: 2,700 kg/m³.
Aluminum round bars are used in automotive parts, aerospace components, robotics, marine trim, hobby projects, lightweight structures, and DIY builds.
If you need an exceptional strength-to-weight ratio for critical applications, aerospace-grade titanium round bars offer a density of about 4,500 kg/m³. This makes them heavier than aluminum but significantly lighter than steel.
Brass and copper round bar
Brass and copper round bars are denser than mild steel, so they can weigh more for the same diameter and length.
Approximate densities:
- Brass: 8,400 to 8,700 kg/m³
- Copper: 8,900 to 8,960 kg/m³
Brass round bar is commonly used for machined fittings, valves, decorative hardware, electrical components, and plumbing parts.
Copper round bar is commonly used for electrical applications, thermal applications, industrial components, plumbing, and fabrication.
For extreme environments and high-temperature applications, specialized Inconel and Incoloy round bars have even higher densities, typically ranging from 8,100 to 8,400 kg/m³. Because these specialty alloys are heavy materials, accurate weight calculation is especially useful for shipping and cost estimation.
Stainless steel vs mild steel weight
Stainless steel is usually slightly heavier than mild steel because its density is slightly higher.
| Material | Approximate Density | Weight Compared to Mild Steel |
|---|---|---|
| Mild Steel | 7,850 kg/m³ | Baseline |
| Stainless Steel 304 | Around 8,000 kg/m³ | Slightly heavier |
| Stainless Steel 316 | Around 8,000 kg/m³ | Slightly heavier |
Example:
A 20 mm mild steel round bar weighs about 2.47 kg/m.
A 20 mm stainless steel round bar may weigh about 2.51 kg/m.
The difference is usually small for a single bar, but it can become significant across large orders, long lengths, or heavy fabrication projects.
Round bar weight chart by diameter
The tables below show theoretical weights for mild steel round bars. These values assume nominal diameter and standard density. Actual weight may vary slightly depending on supplier tolerance and material grade.
Common round bar sizes and weights
Metric mild steel round bar weights:
| Diameter | Weight per Meter | Weight per Foot |
|---|---|---|
| 6 mm | 0.22 kg/m | 0.15 lbs/ft |
| 8 mm | 0.39 kg/m | 0.27 lbs/ft |
| 10 mm | 0.62 kg/m | 0.41 lbs/ft |
| 12 mm | 0.89 kg/m | 0.60 lbs/ft |
| 16 mm | 1.58 kg/m | 1.06 lbs/ft |
| 20 mm | 2.47 kg/m | 1.66 lbs/ft |
| 25 mm | 3.85 kg/m | 2.59 lbs/ft |
| 30 mm | 5.55 kg/m | 3.73 lbs/ft |
| 32 mm | 6.31 kg/m | 4.24 lbs/ft |
| 40 mm | 9.86 kg/m | 6.63 lbs/ft |
| 50 mm | 15.41 kg/m | 10.35 lbs/ft |
Imperial mild steel round bar weights:
| Diameter | Weight per Foot | Weight per Meter |
|---|---|---|
| 1/4 inch | 0.17 lbs/ft | 0.25 kg/m |
| 3/8 inch | 0.38 lbs/ft | 0.56 kg/m |
| 1/2 inch | 0.67 lbs/ft | 0.99 kg/m |
| 5/8 inch | 1.04 lbs/ft | 1.55 kg/m |
| 3/4 inch | 1.50 lbs/ft | 2.24 kg/m |
| 1 inch | 2.67 lbs/ft | 3.98 kg/m |
| 1-1/4 inch | 4.18 lbs/ft | 6.21 kg/m |
| 1-1/2 inch | 6.01 lbs/ft | 8.95 kg/m |
| 2 inch | 10.69 lbs/ft | 15.91 kg/m |
| 3 inch | 24.05 lbs/ft | 35.79 kg/m |
Weight by length
The table below shows estimated mild steel round bar weights for common lengths.
| Diameter | 1 Meter | 2 Meter | 3 Meter | 6 Meter |
|---|---|---|---|---|
| 10 mm | 0.62 kg | 1.23 kg | 1.85 kg | 3.70 kg |
| 12 mm | 0.89 kg | 1.77 kg | 2.66 kg | 5.32 kg |
| 16 mm | 1.58 kg | 3.15 kg | 4.73 kg | 9.46 kg |
| 20 mm | 2.47 kg | 4.93 kg | 7.39 kg | 14.79 kg |
| 25 mm | 3.85 kg | 7.70 kg | 11.55 kg | 23.11 kg |
| 32 mm | 6.31 kg | 12.62 kg | 18.93 kg | 37.86 kg |
| 40 mm | 9.86 kg | 19.72 kg | 29.58 kg | 59.16 kg |
| 50 mm | 15.41 kg | 30.81 kg | 46.22 kg | 92.43 kg |
To calculate total weight manually:
Total Weight = Weight per meter x Length x Quantity
Example:
You need three 2-meter mild steel round bars with a diameter of 25 mm.
3.85 kg/m x 2 m x 3 pieces = 23.1 kg.
The total estimated weight is 23.1 kg.
Why round bar weight matters
Round bar weight matters because it affects cost, shipping, handling, and project planning. Even a small increase in diameter can significantly increase weight, especially when ordering long bars or large quantities.
Estimating shipping weight
Shipping costs often depend on weight and freight class. Metal bars can become heavy quickly, especially when ordering steel in long lengths or large diameters.
Calculating weight before ordering helps you estimate freight charges, avoid unexpected delivery costs, plan for unloading, check transport limits, and prepare safe handling.
For large orders, include packaging, pallets, and bundling weight if the supplier provides that information.
Budgeting and cost estimates
Metal is often priced by weight, length, or piece. Knowing the estimated weight helps you create a more accurate project budget.
Weight calculation helps with comparing supplier quotes, estimating material cost, calculating cost per kilogram or pound, planning material usage, reducing waste, and estimating machining or fabrication costs.
For large projects, even a small weight difference can affect the final cost.
Checking weight before ordering
Checking weight before ordering helps you confirm that the bar is practical for your project.
It helps you answer questions like: Can the bar be carried safely? Can the structure support the weight? Is the bar too heavy for installation? Should I use aluminum instead of steel? Do I need lifting equipment?
This is especially important for large-diameter bars, long lengths, or high-quantity orders.
Total weight for multiple bars or a whole project
Most projects require more than one bar. The calculator includes a quantity field so you can estimate the total weight of the full order.
Formula:
Total Weight = Weight per bar x Number of bars
Example:
If one round bar weighs 8.5 kg and you need 12 bars, 8.5 kg x 12 = 102 kg.
This is useful for procurement teams, fabrication shops, engineers, contractors, and DIY builders.
Metal fabrication use
In metal fabrication, round bar weight is important for planning, handling, machining, welding, and installation.
Fabricators use weight estimates for shafts, rollers, pins, machine components, structural supports, custom brackets, and tooling.
Accurate weight estimation helps fabrication shops improve quotes, reduce errors, and plan safe handling.
DIY and home workshop use
DIY users and home workshop builders also benefit from calculating round bar weight before buying material.
Common DIY uses include gates, railings, trailer parts, tool stands, shop fixtures, repair projects, decorative metalwork, automotive fabrication, and off-road builds.
Knowing the weight helps you decide whether the material can be handled, mounted, welded, or supported safely.
Calculated weight vs actual supplier weight
The calculator provides a theoretical weight based on standard density, nominal diameter, and an ideal cylindrical shape.
Actual supplier weight may differ due to diameter tolerance, length tolerance, material grade, mill scale, surface finish, heat treatment, cutting loss, packaging weight, and supplier scale measurement.
For example, a bar listed as 20 mm may measure slightly under or over 20 mm depending on manufacturing tolerance. A small diameter difference can change the weight, especially across long lengths or large quantities.
For general estimates, the calculator is very useful. For procurement, freight, engineering, or legal weight verification, confirm the final weight with your trusted metal supplier, Euro Steel Bars, to ensure exact scale accuracy and certified mill test reports for your project.
Frequently Asked Questions about Round Bar Weight
How much does a round steel bar weigh per foot?
A standard steel round bar weighs approximately diameter squared x 2.67 pounds per foot when the diameter is measured in inches. For example, a 1-inch steel round bar weighs about 2.67 lbs/ft, while a 2-inch bar weighs about 10.68 lbs/ft. This is a theoretical weight based on nominal size and standard steel density. Actual weight can vary slightly with alloy and manufacturing tolerance.
How much does a 3/4 inch round bar weigh per foot?
A 3/4-inch steel round bar weighs about 1.50 pounds per foot. The calculation is 0.75 x 0.75 x 2.67, which equals approximately 1.503 lbs/ft. This estimate assumes standard mild steel or carbon steel with nominal diameter. If the bar is stainless steel or has a non-standard tolerance, the actual weight may be slightly different.
How heavy is a 1 inch round steel bar per foot?
A 1-inch steel round bar weighs approximately 2.67 pounds per foot. The quick formula is 1² x 2.67 = 2.67 lbs/ft for standard steel. This is useful for estimating material cost, shipping weight, and fabrication loads. Stainless steel may weigh slightly more because its density is usually a little higher than mild steel.
How much does a 1/2 inch round bar weigh per foot?
A 1/2-inch steel round bar weighs about 0.67 pounds per foot. Use the formula 0.5 x 0.5 x 2.67, which gives approximately 0.6675 lbs/ft. This is a theoretical weight for standard steel round stock using nominal dimensions. Actual bar weight may vary slightly due to diameter tolerance, surface condition, and alloy.
How do I find the weight of steel round stock?
To find the weight of steel round stock, multiply the bar volume by steel density. For metric sizes, use diameter in mm squared x 0.006162 to get kg per meter. For imperial sizes, use diameter in inches squared x 2.67 to get pounds per foot. Then multiply by length and quantity to get the total weight.
Can I calculate round bar weight without a scale?
Yes, you can calculate round bar weight without a scale by using diameter, length, and material density. The formula is weight = volume x density, where volume equals π x radius² x length. Online calculators automate this and reduce math errors. However, calculated results are theoretical, so actual weight may vary with tolerances.
Is an online calculator as accurate as the manual formula?
Yes, a good online calculator uses the same volume x density formula as manual calculation. It can be more accurate because it stores correct material densities and converts units automatically. The result is still an estimate unless you enter exact dimensions and density. For critical engineering or shipping, verify values with supplier data.
Is the calculated weight exact?
The calculated weight is theoretical, not exact. It assumes a perfect cylinder, nominal diameter, and standard material density. Real bars can vary because of manufacturing tolerance, surface finish, scale, moisture, heat treatment, or alloy composition. For procurement or freight, always use the supplier certified weight when exact accuracy is required.
Why does the supplier weight differ from the calculated weight?
Supplier weight can differ because actual bar diameter may be slightly under or over nominal size. Suppliers may also use actual scale weights, bundled weights, or different density assumptions. Manufacturing tolerance, mill scale, cutting loss, and packaging can affect total weight. Treat calculator results as estimates unless confirmed by the supplier.
Does material grade change the weight?
Material grade can change weight slightly because different alloys have different densities. For example, stainless steel is usually a little denser than mild steel, so the same size bar may weigh slightly more. Aluminum grades also vary, but the difference is usually smaller. For precise calculations, enter the exact density for the grade.