Flat Bar Weight Calculator
This flat bar weight calculator finds the weight of a steel, stainless, aluminum, brass, or copper flat bar from its width, thickness, and length. Enter the sizes and quantity, and the flat bar weight calculator returns the total weight, the flat bar weight per meter, and the weight per foot.
Results
The Flat Bar Weight Calculator is part of our Weight collection. Browse more weight to size, convert, and check your work alongside this tool.
What the flat bar weight calculator does
A flat bar is a solid rectangle in section, so its weight is simply width times thickness times length times density. The flat bar weight calculator does that in one step for five common metals, then shows the weight per meter and per foot so you can match mill tables and price by weight.
Flat bar weight formula
The section is a rectangle, so:
For steel at 7.85 g/cm³ the flat bar weight formula becomes W × T × 0.00785 kg per meter. Multiply by the length in meters and the quantity for the total.
Flat bar weight calculator example
A steel flat bar 50 mm wide and 10 mm thick, 6 m long:
That is 2.637 lb per foot. The same bar in aluminum weighs about a third as much.
How to use the flat bar weight calculator
Choose the metal, then enter the width and thickness in millimeters, the length of one bar in millimeters, and the number of bars. Press Calculate to read the total weight and the unit weights. For inch sizes, multiply by 25.4: a 2 × 3/8 in bar is 50.8 × 9.525 mm.
Reading flat bar weight per meter
The weight per meter is fixed for a size and metal, so it is the figure to compare with a supplier list; the total covers your cut list. Weight rises in direct proportion to both width and thickness, so a 100 × 10 bar weighs twice a 50 × 10 bar. Rolled bars have slightly rounded edges and a mill tolerance, so the delivered weight can differ by a percent or two.
When to use a steel flat bar weight calculator
- Pricing flat bar sold by weight
- Planning loads for brackets, gates, and frames
- Checking a delivery note
- Comparing steel with aluminum flat bar
- Estimating weight of base plates and straps
Common flat bar weight calculator mistakes
- Mixing units. Enter mm for width, thickness, and length.
- Wrong metal. Set aluminum or stainless when the bar is not steel.
- Forgetting quantity. The total covers all bars only with the count entered.
- Ignoring cut waste. Add a few percent for saw cuts and offcuts.
Tips for flat bar weight takeoffs
- Group bars by size before adding totals.
- Order in stock lengths, usually 6 m or 20 ft.
- Check supplier tolerance for heavy orders.
MS flat bar weight calculator in practice
Fabricators often keep an ms flat weight chart pinned to the wall, but the arithmetic behind it is simple enough to check by hand. One square millimeter of steel section weighs 7.85 grams per meter, so a 40 × 8 bar of 320 mm² weighs 2.512 kg/m. In inches, one square inch of steel weighs about 3.4 lb per foot, so a 2 × 1/4 in bar of 0.5 in² weighs 1.70 lb/ft. That shortcut is why mill tables for flat bar look so regular. For square stock use the same idea with equal sides, or the square bar weight calculator.
Aluminum and stainless steel flat bar weight
Only the density changes between metals. Stainless steel at about 8.0 g/cm³ runs 2% heavier than carbon steel. Aluminum at 2.70 g/cm³ weighs about 34% of steel, so a 50 × 10 aluminum bar is 1.35 kg/m. Brass and copper are heavier than steel at about 8.5 and 8.96. Once a flat bar gets wide and thin it is sold as strip or sheet; for that, the sheet metal weight calculator or the hex bar weight calculator for six sided stock covers the other shapes.
Steel flat bar weight chart
Steel flat bar weight from W × T × 7.85 ÷ 1000:
| Size (mm) | kg per meter | lb per foot | kg per 6 m |
|---|---|---|---|
| 25 × 5 | 0.981 | 0.659 | 5.89 |
| 30 × 6 | 1.413 | 0.949 | 8.48 |
| 40 × 8 | 2.512 | 1.688 | 15.07 |
| 50 × 6 | 2.355 | 1.582 | 14.13 |
| 50 × 10 | 3.925 | 2.637 | 23.55 |
| 75 × 10 | 5.888 | 3.956 | 35.33 |
| 100 × 10 | 7.850 | 5.275 | 47.10 |
| 100 × 12 | 9.420 | 6.330 | 56.52 |
Flat Bar Weight Calculator FAQ
What is the flat bar weight formula?
Weight in kg per meter equals width × thickness in mm × density in g/cm³ ÷ 1000. For steel that is W × T × 0.00785.
How much does a 50 × 10 mm flat bar weigh?
A 50 × 10 mm steel flat bar weighs 3.925 kg per meter, or 23.55 kg for a 6 m length.
Is MS flat bar the same weight as other steel?
Yes. Mild steel and most carbon steels share a density near 7.85 g/cm³, so their flat bar weight is the same for the same size.
How do I weigh flat bar in inches?
Convert to millimeters by multiplying by 25.4, or use lb/ft = width × thickness in inches × 3.4 for steel.