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Steel Weight Calculator

Instantly calculate unit weight, total weight (in kg, quintals, and tonnes), and estimated bundles for standard TMT bars used in construction.

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IS 1786 / NS 191 Compliant

* Calculated using structural steel density: 7850 kg/m³

Standard Unit Weight Reference (d²/162):

8mm0.40
10mm0.62
12mm0.89
16mm1.58
20mm2.47
25mm3.86
28mm4.84
32mm6.32

Frequently Asked Questions (FAQs)

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Engineering Theory

The Math Behind Steel Weight Calculation

The standard calculation for the unit weight of a circular steel reinforcement bar (rebar) is derived from the constant density of steel, which is 7,850 kg/m³.

Standard FormulaWeight (kg/m) = D² / 162

*Where D is the nominal diameter of the bar in millimeters. This formula is universally used by civil engineers on construction sites to quickly verify delivery quantities without needing to weigh massive bundles of steel.

Standard Steel Grades

In Nepal, Thermo Mechanically Treated (TMT) bars are generally available in grades such as Fe415, Fe500, and Fe550 (as per IS:1786 specifications). The "Fe" denotes Iron, and the number denotes the minimum yield stress in N/mm². Note: The grade of the steel changes its strength, but it does not change its weight or density.

How to Use the Steel Calculator

  1. Select the Diameter: Choose the standard bar size (e.g., 10mm, 12mm, 16mm) from your structural drawings.
  2. Input Length: Enter the cut length of a single bar. Standard factory bars are exactly 12 meters (40 feet) long.
  3. Enter Bar Count: Input the total number of bars required for the footing, column, or slab.
  4. Add Wastage: Always order approximately 3% to 5% extra steel to account for cutting, overlapping (lap splices), and bending wastage on site.