Quick answer: MS flat weight per metre = width (mm) × thickness (mm) × 0.00785. For example, a 50 × 6 mm flat weighs 2.36 kg/m and a 75 × 10 mm flat weighs 5.89 kg/m.
MS flat weight chart (kg per metre)
| Size | Width (mm) | Thickness (mm) | Weight (kg/m) | Per 6 m length (kg) |
|---|---|---|---|---|
| 25 × 5 mm | 25 | 5 | 0.98 | 5.9 |
| 32 × 6 mm | 32 | 6 | 1.51 | 9.1 |
| 40 × 6 mm | 40 | 6 | 1.88 | 11.3 |
| 50 × 6 mm | 50 | 6 | 2.36 | 14.2 |
| 50 × 8 mm | 50 | 8 | 3.14 | 18.8 |
| 50 × 10 mm | 50 | 10 | 3.93 | 23.6 |
| 65 × 8 mm | 65 | 8 | 4.08 | 24.5 |
| 75 × 8 mm | 75 | 8 | 4.71 | 28.3 |
| 75 × 10 mm | 75 | 10 | 5.89 | 35.3 |
| 100 × 10 mm | 100 | 10 | 7.85 | 47.1 |
| 100 × 12 mm | 100 | 12 | 9.42 | 56.5 |
| 125 × 12 mm | 125 | 12 | 11.77 | 70.6 |
| 150 × 12 mm | 150 | 12 | 14.13 | 84.8 |
| 150 × 16 mm | 150 | 16 | 18.84 | 113.0 |
| 200 × 20 mm | 200 | 20 | 31.4 | 188.4 |
Theoretical weights using steel density 7,850 kg/m³. Billing is on weighbridge weight. Try the weight calculator or see MS flats.
Weight Calculation Formula
For mild steel flat bar, approximate weight per meter is calculated as width in mm multiplied by thickness in mm multiplied by 0.00785. For example, 50x6 MS Flat weighs about 2.355 kg per meter.
This formula is useful for planning, but actual supply weight can vary slightly because of rolling tolerance and length variation.
Common Reference Weights
25x5 mm is about 0.981 kg/m, 30x5 mm is about 1.178 kg/m, 40x5 mm is about 1.570 kg/m, 50x5 mm is about 1.963 kg/m, 50x6 mm is about 2.355 kg/m and 75x6 mm is about 3.533 kg/m.
For project procurement, use these numbers to estimate total tonnage and truck loading, then confirm final weight through weighbridge slips.
How Buyers Should Use the Chart
A fabricator can multiply kg per meter by total running meter requirement. A contractor can use it to compare two supplier quotes where one quote is in pieces and another is in kilograms.
For repeat purchases, maintain a small size-wise table in the purchase file so future enquiries can be issued faster and with fewer specification mistakes.
Required Inputs
The calculator needs width in mm, thickness in mm, length in meters and quantity. If the order is in standard commercial lengths, confirm whether the supplier is quoting 6 meter, 12 meter or custom cut lengths.
For mixed-size orders, calculate each size separately and then add the totals.
Example Calculation
For 50x6 MS Flat in 6 meter length, per meter weight is 2.355 kg. One 6 meter piece weighs about 14.13 kg. If the requirement is 100 pieces, estimated total weight is about 1,413 kg.
This helps the purchase team compare rate per kg, freight cost and loading plan before issuing the final purchase order.
Mistakes to Avoid
Do not enter centimeters instead of millimeters. Do not assume every supplier length is the same. Do not use calculated weight alone for final reconciliation if the commercial agreement is based on actual weighment.
For critical structures, calculation should support procurement planning, while engineering approval should decide section suitability.
How Sizes Are Written
MS Flat sizes are usually written as width x thickness, such as 40x5 mm or 50x6 mm. Length is mentioned separately because suppliers may stock different commercial lengths.
A clear enquiry should say: MS Flat 50x6 mm, required quantity, length preference, delivery city and grade if specified.
Choosing Thickness
Thickness affects stiffness, weld area and weight. A 50x6 flat is stronger and heavier than a 50x5 flat, but it also increases material cost.
For non-structural fabrication, practical experience may guide selection. For load-bearing work, use engineer-approved sizes.
Availability and Cutting
Common sizes are usually easier to source quickly. Rare sizes or exact cut lengths may need more lead time, especially during busy market periods.
If cutting is required, mention tolerance, edge finish and bundling expectations before the material is dispatched.
At a glance: what to check
Each row covers one part of this topic, what it involves, the points to confirm and a practical tip.
| Topic | What it covers | Confirm | Tip |
|---|---|---|---|
| Standard Lengths: Buyer Notes | standard lengths, commercial supply, transport and unloading planning | length availability, truck access, storage space and cutting requirement | Confirm whether the supplier is quoting standard length or custom cut length. |
Related guides
FAQs
What is the weight of 50x6 MS Flat?
Approximate weight is 50 x 6 x 0.00785 = 2.355 kg per meter.
Can the chart be used for billing?
It is useful for estimation. Billing should follow agreed terms and actual weighment where applicable.
Why does actual weight vary?
Rolling tolerance, cutting length and surface condition can create small variation from theoretical weight.
What density is used for MS Flat calculation?
The common commercial factor uses steel density around 7,850 kg per cubic meter, simplified as 0.00785 in the formula.
Can I calculate total tonnage from pieces?
Yes. Calculate per piece weight and multiply it by the number of pieces.
Does galvanizing change weight?
Galvanizing can add a small coating weight, so confirm final billing terms for coated material.
What are common MS Flat sizes?
Common sizes include 25x5, 30x5, 40x5, 50x5, 50x6, 65x6, 75x6 and 100x6 mm.
Is wider MS Flat always stronger?
Strength depends on width, thickness, orientation, span and application, so size should match the use case.