Steel weight calculator for TMT bars, rebar and sections
This steel weight calculator gives the weight of reinforcement bars in kg per metre, per bar and for a whole bar list, and the weight of plates, flats, pipes, hollow sections and angles. Choose Indian TMT sizes from 6 to 40 mm (IS 1786) or US rebar from #3 to #18 (ASTM A615), enter how many bars of each size and how long they are, and it adds them up in kilograms, tonnes and pounds — with a cost if you enter the steel price.
Site engineers, contractors, students and home builders use it to check a bar bending schedule, order steel by the tonne, compare a supplier’s weighbridge slip with the theoretical weight, or simply look up the TMT bar weight chart. The chart under the calculator lists the nominal mass of every IS 1786 size next to the quick D²/162 figure, the weight of a 12 m bar and a typical bundle, and the mass tolerance the standard allows.
Everything is calculated in your browser as you type. The figures are theoretical nominal weights; real bars vary within the tolerances shown, so check your structural drawings and supplier documents before ordering.
How to use the Steel Weight Calculator
- Pick TMT / rebar for reinforcement or Plate, pipe, sections for other steel, and choose metric or imperial units.
- For bars, choose IS 1786 or US # sizes, then enter each bar size, the number of bars and the length of each bar. Use Add bar size for more rows.
- Choose whether the mass per metre comes from the standard’s table or the D² ÷ 162 formula, and add a percentage for laps and offcuts if you want one.
- For sections, choose the shape and material, then enter the dimensions, length and number of pieces.
- Enter the steel price per kg, tonne, lb or US ton to see the cost, then copy the summary or download the bar list as CSV.
Steel Weight Calculator features
IS 1786 and ASTM A615 tables
Nominal masses for 6–40 mm TMT and #3–#18 rebar, straight from the standards, with the formula alongside.
Bar lists, not just one bar
Add as many sizes as you need; each row shows the weight of one bar, the row total and typical bundles.
Plate, pipe and sections
Round and square bar, flat and plate, round pipe, rectangular hollow sections and angles, with editable density.
Every unit
Kilograms, tonnes and pounds together, lengths in metres or feet, prices per kg, tonne, lb or US ton.
Weight chart with tolerances
The IS 1786 chart shows kg per 12 m bar, bundle weights and the Table 2 mass tolerances.
The D²/162 formula: where it comes from
Steel weighs 7,850 kg per cubic metre — IS 1786 puts it as 0.00785 kg per mm² of cross-section per metre of length. A bar of diameter D mm has an area of πD²/4 mm², so one metre weighs πD²/4 × 0.00785 = D² × 0.006165 kg, which is D² ÷ 162.2. Rounded to D² ÷ 162, it is the formula every site engineer remembers.
Worked example: a 12 mm bar weighs 144 ÷ 162 = 0.889 kg/m, so a 12 m length weighs 10.67 kg and ten of them 106.7 kg. The IS 1786 table gives 0.888 kg/m (10.66 kg per bar), because the standard rounds the area. The difference is tiny; billing usually uses the table value or the actual weighed weight.
In imperial units the same idea gives lb/ft = 2.67 × d² with d in inches: a #4 bar (½ in) is 0.668 lb/ft, matching ASTM A615 Table 1.
Unit weight of steel as per IS code: tolerances
IS 1786:2008 Table 2 allows bars to differ from the nominal mass by these percentages. The batch figure applies to the average of samples from a lot; the individual figure is the most a single sample may be under weight.
| Nominal size | Batch | Individual sample | Coils |
|---|---|---|---|
| Up to and including 10 mm | ±7% | −8% | ±8% |
| Over 10 mm up to 16 mm | ±5% | −6% | ±6% |
| Over 16 mm | ±3% | −4% | ±4% |
Tips for estimating and ordering steel
- Indian TMT is sold in 12 m lengths and by weight; dealers bundle bars (often 10 × 8 mm, 7 × 10 mm, 5 × 12 mm, 3 × 16 mm, 2 × 20 mm), but bundle counts vary by maker, so the bundle column is only a guide.
- US rebar stock lengths are 20, 40 and 60 ft. A #5 bar 20 ft long weighs 20.9 lb.
- Add 3–5% for laps, hooks and offcuts if your bar list does not already include them, or work out laps and spacing in the rebar calculator.
- Concrete volumes and cement bags for the same slab are in the concrete calculator; a whole-house budget is in the house construction cost calculator.
Steel Weight Calculator FAQ
What is the formula for steel weight?
For a round bar, weight in kg per metre = D² ÷ 162, where D is the diameter in mm. For any shape, weight = cross-section area × length × density, with steel at 7,850 kg/m³. This steel weight calculator uses both and shows the area it used.
What is the weight of a 12 mm TMT bar?
IS 1786 gives 0.888 kg per metre, so a standard 12 m bar weighs about 10.66 kg. The D²/162 formula gives 0.889 kg/m and 10.67 kg.
What is the unit weight of steel as per IS code?
IS 1786 takes steel as 0.00785 kg per mm² per metre, which is 7,850 kg/m³ (78.5 kN/m³). The nominal masses in its Table 1 are calculated from that density.
How much does a #4 rebar weigh?
ASTM A615 lists #4 (13 mm) bar at 0.668 lb/ft or 0.994 kg/m, so a 20 ft bar weighs 13.4 lb and a 40 ft bar 26.7 lb.
Why does my weighed steel differ from the calculation?
Bars are rolled within tolerances (for example ±5% for a batch of 12 mm bars under IS 1786), and lengths vary slightly. Weighbridge weight is what you are billed for; the calculation tells you whether it is reasonable.
Can it calculate MS plate and pipe weight?
Yes. Choose Plate, pipe, sections, pick the shape and enter the dimensions. A 2 in schedule 40 pipe (60.3 × 3.91 mm) works out at 5.44 kg/m. Stainless steel uses 7,930 kg/m³, or enter your own density.