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Steel Weight Calculator

Construction

Calculate the weight of a solid steel bar in round, square, or rectangular cross-section. Enter dimensions, length, and quantity for instant weight in pounds.

Reviewed by the thecalcu.com team · Last updated July 8, 2026

0.124
0.124
11,200
1

Total Weight

68.06
Weight per Piece
68.06

This calculator computes your Total Weight, Weight per Piece from the values you enter.

Inputs
Bar ShapeDiameter / Side 1Side 2 (rectangular only)LengthQuantity
Outputs
Total WeightWeight per Piece

What is a Steel Weight?

A Steel Weight Calculator determines the weight of a solid steel bar in round, square, or rectangular cross-section, based on its dimensions, length, and quantity. Steel bar stock is priced and shipped by weight, and structural or machining calculations depend on accurate mass figures, so knowing a bar's exact weight before ordering or fabrication saves both money and a lot of guesswork.

This calculator uses a fixed steel density (0.2836 lb per cubic inch) and supports three common bar profiles in one tool, so you're not switching between separate calculators for round, square, and rectangular stock. It pairs well with the Steel Plate Weight Calculator for flat plate stock, the Pipe Weight Calculator for tubular sections, and the Metal Weight Calculator for other metals like aluminum, brass, and copper.

How to use this Steel Weight calculator

  1. Select the Bar Shape, Round, Square, or Rectangular.
  2. Enter Dimension 1 in inches, the diameter for round bars, or the side length for square and rectangular bars.
  3. If you selected Rectangular, enter Dimension 2 for the second side length.
  4. Enter the Length in inches and set the Quantity for your order.
  5. Read the Total Weight result for your full order, and check Weight per Piece for a single bar's weight.
Show formula & methodology ↓Show less ↑

Formula & Methodology

The calculator computes cross-sectional area based on the selected shape, then multiplies by length and the density of steel:

Round: Area = π × (Dimension 1 ÷ 2)²

Square: Area = Dimension 1²

Rectangular: Area = Dimension 1 × Dimension 2

Weight per Piece = Area × Length × 0.2836 lb/in³

Total Weight = Weight per Piece × Quantity

Worked example (round): For a 1 in diameter round bar, 120 in long, quantity 1: Area = π × (1 ÷ 2)² ≈ 0.785 in². Weight per Piece = 0.785 × 120 × 0.2836 ≈ 26.72 lb. Total Weight = 26.72 lb.

Why Use a Steel Weight Calculator?

Ordering steel bar stock without knowing its weight makes freight quotes and material budgets unreliable, especially on jobs requiring long lengths or large quantities. If you're fabricating structural framing, machine components, or custom hardware, knowing the exact weight per piece and total order weight up front avoids unpleasant surprises when the shipment, and the invoice, arrives.

It's also useful for quick material cost comparisons across shapes. Since round bar weighs noticeably less than square bar of the same outer dimension, this calculator makes it easy to see the weight, and therefore cost, difference before committing to a profile.

Common Mistakes to Avoid

Confusing diameter with radius when calculating by hand. The round bar formula uses radius (half the diameter), and plugging in the full diameter instead roughly quadruples the calculated weight, a common error when working from a supplier spec sheet listed in diameter.

Assuming a round and square bar of the same outer dimension weigh the same. They don't, a round bar's circular cross-section covers only about 78.5% of the area of a square with the same width, so swapping profiles without recalculating weight can throw off both cost and load estimates.

Using the wrong density for alloy or stainless steel. The 0.2836 lb/in³ figure used here is standard for mild carbon steel. Stainless and some alloy steels run slightly higher, so for tightly specified structural or aerospace work, confirm density against the actual alloy's mill certification rather than this general-purpose estimate.

Skipping the quantity multiplier on bulk orders. It's easy to calculate weight per piece correctly and then forget to multiply by quantity before requesting a freight quote, resulting in a shipping estimate that's off by whatever multiple of bars you actually ordered.

Quick Reference

Shape Cross-sectional area formula
Round π × (Diameter ÷ 2)²
Square Side²
Rectangular Side 1 × Side 2

For other stock shapes, see the Steel Plate Weight Calculator for flat sheet, the Pipe Weight Calculator for hollow tube and pipe, or the Rebar Calculator for reinforcement bar quantities on a concrete pour.

Frequently Asked Questions

How do I calculate the weight of a steel bar?
Steel bar weight comes from multiplying the cross-sectional area by the bar's length and the density of steel (0.2836 lb per cubic inch). This calculator handles that automatically for round, square, or rectangular bars, pick your shape and enter the dimensions.
What is the formula for round steel bar weight?
For a round bar, cross-sectional area equals π times the radius squared (radius being half the diameter), and weight per piece equals that area multiplied by length and the steel density of 0.2836 lb per cubic inch. This calculator applies that formula automatically when you select the Round shape option.
What is the formula for square and rectangular steel bar weight?
For a square bar, cross-sectional area is simply the side length squared. For a rectangular bar, area is the first side length multiplied by the second side length. Both cases use the same weight formula: area multiplied by length and the steel density of 0.2836 lb per cubic inch.
What density does this calculator use for steel?
This calculator uses a standard mild steel density of 0.2836 lb per cubic inch (about 7,850 kg per cubic meter), the widely accepted figure for carbon and mild steel bar stock. Stainless or alloy steel varies slightly from this, typically by less than 5%, so treat results as a close estimate rather than a mill-certified figure for those alloys.
How much does a 1 inch round steel bar weigh per foot?
A 1 in diameter round steel bar weighs approximately 2.67 lb per linear foot, based on the standard steel density used here. This is a commonly referenced figure in fabrication and machining shops for quick length-to-weight conversions without pulling out a calculator.
How do I use the Steel Weight Calculator?
Select the Bar Shape, Round, Square, or Rectangular. Enter Dimension 1 (diameter for round, side length for square, or the first side for rectangular), and enter Dimension 2 only if you selected Rectangular. Set the Length and Quantity, and the calculator returns Total Weight and Weight per Piece.
What's the difference between round, square, and rectangular bar weight calculations?
The three shapes only differ in how cross-sectional area is calculated, round bars use a circle's area formula, square bars use side-squared, and rectangular bars multiply two different side lengths. Once area is known, the weight formula (area × length × density) is identical across all three.
Why does bar shape affect weight so much for the same outer dimension?
A round bar has less cross-sectional area than a square bar with the same outer dimension, since a circle inscribed in a square only covers about 78.5% of the square's area. That means a round bar weighs noticeably less than a square bar of the same diameter/side and length, worth knowing before you assume two profiles are interchangeable by weight.
How is steel bar weight used for shipping and material cost estimates?
Steel bar stock is typically priced and shipped by weight, so an accurate total weight figure is essential for getting a correct freight quote and calculating material costs before ordering. Multiply total weight by your supplier's price per pound to get an accurate cost estimate ahead of time, rather than being surprised at checkout.
What length and dimension range does this calculator support?
It supports bar dimensions from 0.1 in up to 24 in for diameter or side length, and lengths from 1 in up to 1,200 in (100 ft), covering everything from small precision stock to long structural bar and rod lengths in one tool.
Does this calculator account for tolerance or mill overrun in actual bar weight?
No, it computes theoretical weight based on nominal dimensions and standard density, which is the industry-standard way to estimate before ordering. Actual delivered weight can vary slightly due to manufacturing tolerances and mill rounding practices, so for large orders, confirm final billed weight against your supplier's certified mill test report rather than relying solely on a calculated estimate.
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