A steel bar weighs D² / 162 kg per metre, where D is the diameter in millimetres. A #4 bar (4 soot, 1/2 inch, 12.7 mm) therefore weighs 0.996 kg per metre or 0.303 kg per foot. A 30 ft length is about 9.1 kg.
Enter how many bars of each size you need and their length. The calculator adds up the weight and prices it at the steel rate you give it, per kg or per ton.
Steel bar weight chart (soot sizes)
| Bar | Diameter | kg per metre | kg per foot | Feet in one ton |
|---|---|---|---|---|
| #3 (3 soot, 3/8 inch) | 9.52 mm | 0.560 | 0.171 | 5,858 |
| #4 (4 soot, 1/2 inch) | 12.70 mm | 0.996 | 0.303 | 3,295 |
| #5 (5 soot, 5/8 inch) | 15.88 mm | 1.556 | 0.474 | 2,109 |
| #6 (6 soot, 3/4 inch) | 19.05 mm | 2.240 | 0.683 | 1,465 |
| #7 (7 soot, 7/8 inch) | 22.22 mm | 3.049 | 0.929 | 1,076 |
| #8 (8 soot, 1 inch) | 25.40 mm | 3.982 | 1.214 | 824 |
Pakistani mills also label bars in millimetres. A "4 soot" or #4 bar is 1/2 inch (12.7 mm) and a "3 soot" bar is 3/8 inch (9.5 mm). One soot is 1/8 inch.
Metric bar weights
| Bar | Diameter | kg per metre | kg per foot | Feet in one ton |
|---|---|---|---|---|
| 8 mm | 8 mm | 0.395 | 0.120 | 8,305 |
| 10 mm | 10 mm | 0.617 | 0.188 | 5,315 |
| 12 mm | 12 mm | 0.889 | 0.271 | 3,691 |
| 16 mm | 16 mm | 1.580 | 0.482 | 2,076 |
| 20 mm | 20 mm | 2.469 | 0.753 | 1,329 |
| 25 mm | 25 mm | 3.858 | 1.176 | 850 |
| 32 mm | 32 mm | 6.321 | 1.927 | 519 |
Use the "Other bar" row in the calculator for a metric size.
How to calculate the weight of steel
Steel weighs 7,850 kg per cubic metre. A bar of diameter D mm has a cross section of π x D² / 4 square mm. One metre of it weighs π x D² / 4 x 7,850 / 1,000,000 kg, which works out to D² / 162.2. Builders round this to D² / 162.
- Per foot: divide by 531.5 instead, so a 12 mm bar is 144 / 531.5 = 0.271 kg per foot.
- From soot: D in mm is soot x 3.175, so kg per foot is about 0.019 x soot². A 5 soot bar: 0.019 x 25 = 0.47 kg per foot.
Worked example
The calculator's example is a small slab and beams: 120 bars of #3 at 20 ft, 80 bars of #4 at 30 ft and 24 bars of #5 at 30 ft.
| Bars | Length | Weight |
|---|---|---|
| #3, 120 x 20 ft | 2,400 ft (731.5 m) x 0.560 kg/m | 409.7 kg |
| #4, 80 x 30 ft | 2,400 ft (731.5 m) x 0.996 kg/m | 728.3 kg |
| #5, 24 x 30 ft | 720 ft (219.5 m) x 1.556 kg/m | 341.4 kg |
| Total | 1,479.4 kg |
At Rs 262 a kg (Grade 60, 26 September 2026) that is Rs 387,600.
Steel rate and grades
Dealer rates reported on 26 September 2026 were Rs 258 a kg for Grade 40 and Rs 262 a kg for Grade 60 bars, or about Rs 262,000 a ton. Grade 60 is the usual choice for house construction. Rates change often, so check with your dealer before ordering.
Steel is sold by weight. Rolled bars can be slightly lighter than their nominal size, so if a dealer sells by the piece, weigh a few bars against the chart above. For a whole house, the builders' rule of about 3.3 kg per sq ft of covered area is used in the construction cost calculator.
Steel questions
What is the weight of a 12 mm steel bar per foot?
0.271 kg per foot, or 0.889 kg per metre, from D² / 162. A #4 (1/2 inch) bar is slightly thicker at 12.7 mm and weighs 0.303 kg per foot. A 40 ft length of 12 mm bar weighs about 10.8 kg.
How many feet of #4 bar are in one ton?
About 3,295 feet, because one foot weighs 0.303 kg and 1,000 / 0.303 is 3,295. For #3 bar it is about 5,858 feet and for #5 about 2,109 feet.
What is the formula for steel weight?
Weight in kg per metre = D² / 162, with D the bar diameter in millimetres. Multiply by the total length in metres for the weight. For feet, use D² / 531.5 kg per foot. The formula comes from the density of steel, 7,850 kg per cubic metre.
What does 3 soot or 4 soot mean?
Soot is the local name for one eighth of an inch. A 3 soot bar is 3/8 inch (about 10 mm), 4 soot is 1/2 inch (about 12 mm) and 6 soot is 3/4 inch (about 19 or 20 mm). The same sizes are called #3, #4 and #6 on drawings.
Last reviewed 30 September 2026. Results are estimates; official notices always take precedence.