Rebar Sizes and Weight Chart (8 mm to 32 mm)
Reinforcement bar sizes and weights: kg per metre, kg per 12 m bar, bars per tonne and cross-sectional area for 8–32 mm rebar, with the d²/162 formula.
Saudi Steel Work Editorial Team · · 3 min read
Short answer: Rebar weight per metre equals d² ÷ 162.2 (d in mm). Common values are 8 mm 0.395 kg/m, 10 mm 0.617, 12 mm 0.888, 16 mm 1.578, 20 mm 2.466, 25 mm 3.853 and 32 mm 6.313 kg/m. A 12 m bar of 16 mm weighs about 18.9 kg.
Rebar is bought by weight but used by length. This chart converts between the two for standard metric diameters.
Rebar weight chart
| Diameter (mm) | Area (mm²) | kg/m | kg per 12 m bar | Bars per tonne (12 m) |
|---|---|---|---|---|
| 8 | 50.3 | 0.395 | 4.74 | 211 |
| 10 | 78.5 | 0.617 | 7.40 | 135 |
| 12 | 113.1 | 0.888 | 10.65 | 93 |
| 14 | 153.9 | 1.208 | 14.50 | 68 |
| 16 | 201.1 | 1.578 | 18.94 | 52 |
| 18 | 254.5 | 1.998 | 23.97 | 41 |
| 20 | 314.2 | 2.466 | 29.59 | 33 |
| 22 | 380.1 | 2.984 | 35.81 | 27 |
| 25 | 490.9 | 3.853 | 46.24 | 21 |
| 28 | 615.8 | 4.834 | 58.00 | 17 |
| 32 | 804.2 | 6.313 | 75.76 | 13 |
Values are nominal (density 7,850 kg/m³). Bars per tonne are rounded down.
The formula
kg/m = d² ÷ 162.2
This comes from π/4 × d² (mm²) × 7,850 kg/m³ ÷ 1,000,000. Many site engineers use d²/162 as a rounded version.
Using the chart
Example: a slab needs 2,400 m of 12 mm bar. 2,400 × 0.888 = 2,131 kg ≈ 2.13 tonnes.
For whole schedules, use our rebar weight calculator.
Imperial bar sizes
Projects designed to US practice may show #3 to #11 bars. These are approximately 9.5 mm to 35.8 mm; confirm metric equivalents with the engineer before ordering.
Related guides
Need rebar? See reinforcement steel or request a quote.