Steel Plate Weight Calculator — Formula, Chart & Examples
Calculating steel plate weight is one of the most frequent tasks in fabrication shops, steel yards, and construction sites. Whether you're estimating material for a base plate, gusset plate, stiffener, or tank shell — you need the weight to order material, plan transport, and estimate cost. This guide covers the formula, a quick reference chart, and worked examples.
Quick Formula: Weight (kg) = Length (m) × Width (m) × Thickness (mm) × 7.85
Or in all-mm: Weight (kg) = L × W × T × 7850 / 1,000,000,000
Where 7850 kg/m³ is the density of mild steel (IS 2062).
For instant calculations with cost estimation, use the Steel Plate Weight Calculator.
Quick Reference — 1m × 1m Plate Weight
Memorize a few of these and you can estimate any plate weight mentally:
| Thickness (mm) | Weight per m² (kg) | Weight per 1.25m × 2.5m plate (kg) |
|---|---|---|
| 5 | 39.3 | 122.7 |
| 6 | 47.1 | 147.2 |
| 8 | 62.8 | 196.3 |
| 10 | 78.5 | 245.3 |
| 12 | 94.2 | 294.4 |
| 16 | 125.6 | 392.5 |
| 20 | 157.0 | 490.6 |
| 25 | 196.3 | 613.3 |
| 32 | 251.2 | 785.0 |
| 40 | 314.0 | 981.3 |
| 50 | 392.5 | 1226.6 |
Steel Flat Weight
Flats are plates with one narrow dimension. Same formula applies:
Weight (kg/m) = Width (mm) × Thickness (mm) × 0.00785
| Flat Size (W × T mm) | Weight (kg/m) | Common Use |
|---|---|---|
| 25 × 3 | 0.59 | Earthing strips |
| 40 × 5 | 1.57 | Cleat plates, stiffeners |
| 50 × 6 | 2.36 | Base plate stiffeners |
| 65 × 8 | 4.08 | Gusset plates |
| 75 × 10 | 5.89 | Base plates, brackets |
| 100 × 10 | 7.85 | Column base plates |
| 150 × 12 | 14.13 | Heavy base plates |
| 200 × 16 | 25.12 | Transfer plates |
Round Bar Weight
Weight (kg/m) = D² × 0.006165
Where D = diameter in mm. (Derived from π/4 × D² × 7850 / 10⁶)
| Diameter (mm) | Weight (kg/m) | Weight per 6m (kg) |
|---|---|---|
| 12 | 0.89 | 5.33 |
| 16 | 1.58 | 9.47 |
| 20 | 2.47 | 14.80 |
| 25 | 3.85 | 23.12 |
| 32 | 6.31 | 37.88 |
| 40 | 9.86 | 59.19 |
| 50 | 15.41 | 92.48 |
| 65 | 26.05 | 156.28 |
| 75 | 34.68 | 208.06 |
| 100 | 61.65 | 369.92 |
Pipe / Hollow Section Weight
Weight (kg/m) = (OD² − ID²) × 0.006165
Or: Weight (kg/m) = (OD − t) × t × 0.02466
Where OD = outer diameter, ID = inner diameter, t = wall thickness (all in mm)
Worked Example
Problem: Calculate the total steel weight for 4 base plates (500 × 500 × 20mm) and 8 gusset plates (300 × 200 × 12mm).
Solution:
- Base plates: 0.5 × 0.5 × 20 × 7.85 × 4 = 157.0 kg
- Gusset plates: 0.3 × 0.2 × 12 × 7.85 × 8 = 45.2 kg
- Total: 202.2 kg
For quick calculations with cost estimation, use the Steel Plate & Pipe Weight Calculator.