Steel Weight Calculator
Calculate weight of TMT bars, flats, angles, and pipes using D²/162 formula.
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What is a Steel Weight Calculator?
A Steel Weight Calculator computes the weight of steel sections using standard formulas. For round bars (TMT rods), the famous D²/162 formula is used, where D is diameter in mm and the result is weight in kg per meter.
Every site engineer and steel fabricator needs this calculation daily - whether ordering reinforcement for RCC, structural steel for fabrication, or verifying supplier invoices. Our calculator supports 5 steel shapes: Round Bar/TMT, Flat Bar, Angle Iron, Square Bar, and Round Pipe.
The tool also provides cost estimation when you enter the rate per kg, helping you budget for procurement.
D²/162 Formula
The standard formula for TMT bar weight. Derived from steel density of 7850 kg/m³.
Multiple Shapes
Round bars, flats, angles, squares, and pipes - all with correct formulas.
Quick Reference
Standard TMT weight chart (6mm to 32mm) for instant reference.
Cost Estimation
Enter rate per kg to get total material cost for budgeting.
How to Calculate Steel Weight
Select Steel Shape
Choose Round Bar/TMT for reinforcement, or other shapes for structural steel.
Enter Dimensions
Diameter for round bars, Width × Thickness for flats and angles.
Specify Quantity
Length per bar (standard 12m) and number of pieces.
Get Results
View weight in kg and MT. Add rate for cost estimation.
TMT Bar Weight Chart (D²/162)
| Diameter | kg/meter | kg/12m rod | Rods/MT |
|---|---|---|---|
| 6mm | 0.222 | 2.66 | 376 |
| 8mm | 0.395 | 4.74 | 211 |
| 10mm | 0.617 | 7.40 | 135 |
| 12mm | 0.888 | 10.66 | 94 |
| 16mm | 1.580 | 18.96 | 53 |
| 20mm | 2.469 | 29.63 | 34 |
| 25mm | 3.858 | 46.30 | 22 |
| 32mm | 6.321 | 75.85 | 13 |
* MT = Metric Ton (1000 kg). Standard rod length assumed 12 meters.
Steel Weight Formulas
Weight = D² / 162 kg/m
Weight = W × T × 7.85 / 1000 kg/m
Weight = (2A-T) × T × 7.85 / 1000 kg/m
Weight = (OD-T) × T × 0.02466 kg/m
Why 162?
The constant 162 comes from steel density (7850 kg/m³):
Weight = π × D² / 4 × 1m × 7850
Weight = 3.14159 × D² / 4 × 7850 / 1000000
Weight = D² × 0.00617
Weight = D² / 162.2 ≈ D² / 162
D in mm, result in kg/meter
Pro Tips for Steel Ordering
Add 5% wastage - For cutting, overlaps, and site losses.
Verify bundle weight - Check weighbridge slip against calculation.
Order in MT - Suppliers quote per Metric Ton for bulk orders.
Check bar length - Standard is 12m, may vary by supplier.
Use BBS - Bar Bending Schedule from structural drawings.
Include cutting length - Hooks and bends add to total length.
Common Use Cases
RCC Construction
Calculate reinforcement steel for slabs, beams, columns from structural drawings.
Steel Fabrication
Estimate weight for gates, grills, structures using angles and flats.
Invoice Verification
Cross-check supplier invoice weight against calculated weight.
Frequently Asked Questions
What is the D²/162 formula?
D²/162 calculates steel bar weight in kg/meter, where D is diameter in mm. Derived from: Weight = Volume × Density = (πD²/4 × 1m) × 7850 kg/m³. Simplifying gives D²/162.2 (rounded to 162). Example: 12mm bar = 12²/162 = 0.888 kg/m.
What is the weight of 12mm TMT bar per meter?
A 12mm TMT bar weighs 0.888 kg per meter (using D²/162 = 144/162 = 0.888). A standard 12m rod weighs 10.66 kg. For 100 rods: 1066 kg or 1.066 MT.
What is the standard length of TMT bars?
Standard TMT rod length is 12 meters (approximately 40 feet). Some suppliers offer 6m, 9m options. Always verify with supplier. Cutting charges may apply for custom lengths.
How to calculate weight of flat bar?
Flat bar weight = (Width × Thickness × 7.85) / 1000 kg/meter. Example: 50mm × 6mm flat = (50 × 6 × 7.85) / 1000 = 2.355 kg/m. Multiply by length for total weight.
How to calculate weight of angle iron?
Angle weight = ((2 × Leg - Thickness) × Thickness × 7.85) / 1000 kg/m. Example: 50×50×5mm angle = ((100-5) × 5 × 7.85) / 1000 = 3.73 kg/m. This assumes equal leg angle.
Why is steel density 7850 kg/m³?
7850 kg/m³ (or 7.85 g/cm³) is the standard density of mild steel and TMT. Stainless steel is slightly higher (~7900-8000). This constant is used in all weight formulas.
What is the difference between MT and Quintal?
1 Metric Ton (MT) = 1000 kg. 1 Quintal = 100 kg. Steel is typically ordered in MT. For small quantities, suppliers may quote per quintal or per kg.
How much steel is needed for 1000 sq ft house?
Rule of thumb: 4-5 kg steel per sq.ft for residential construction. For 1000 sq.ft: 4000-5000 kg (4-5 MT). This varies by design - RCC frame needs more than load-bearing structure.
What are common TMT bar sizes?
Common sizes: 8mm (stirrups), 10mm (slabs), 12mm (beams/columns), 16mm (main bars), 20mm (heavy columns), 25mm (foundations). 32mm used for special structures. Always follow structural drawings.
How to convert steel length to weight for ordering?
- List all bars by diameter from structural drawings. 2. Calculate total length for each diameter (cutting length × quantity). 3. Multiply by unit weight (D²/162). 4. Add 5% wastage. 5. Order total in MT.