What is the density of mild steel round bar?

Mild steel (MS) has a density of 7,850 kg/m³ or 7.85 g/cm³. This is the standard value used across the steel industry in India and globally as per IS 1731 standards. In imperial units, mild steel density is approximately 490 lb/ft³. EN8 steel has the same density as MS (7,850 kg/m³), while stainless steel SS 304 is slightly higher at 8,000 kg/m³.

Round Bar Weight Calculator

Units

Material

Diameter (mm)

Length (m)

Quantity

Cost estimate

Use price per kg for the selected units.

Round Bar · Mild Steel (MS)

⌀10 mm · 1 m each

Total weight

0.62kg

1.36 lb

Weight Breakdown

Linear weight, dimensions, and material details

Weight per meter

0.617kg/m

0.414 lb/ft

Weight per foot

0.414lb/ft

0.617 kg/m

Cross-section area

78.54 mm²

0.1217 in²

Volume per piece

78.54 cm³

4.7928 in³

Formula Used

The exact formula applied for round bar weight

Round Bar

Weight (kg) = π × (d/2)² × 10⁻⁶ × L × ρ × Q

d = diameter (mm) · π × (d/2)² = cross-section area (mm²) · L = length (m) · ρ = density (kg/m³) · Q = quantity

Density (ρ) = 7850 kg/m³ (Mild Steel (MS))

How to Use the Round Bar Weight Calculator

Calculate round bar weight in seconds with these 4 simple steps

Select Material

Choose from 6 preset materials — Mild Steel (MS, 7,850 kg/m³), Stainless Steel SS 304 (8,000 kg/m³), EN8 Steel (7,850 kg/m³), Aluminum (2,700 kg/m³), Brass (8,530 kg/m³), and Copper (8,960 kg/m³). Use Custom Density for any other material or alloy.

Enter Dimensions & Quantity

Input the diameter and length in metric (mm, m) or imperial (in, ft). The calculator converts between units automatically. Adjust quantity for batch orders and optionally enable cost estimation per kg or lb.

Review the Results

Get total weight in kg and lb, weight per meter (kg/m), weight per foot (lb/ft), cross-section area (mm²), volume (cm³), and optional cost estimate in your selected currency.

Use the Formula Reference

The results card shows the exact formula used with your current values — π × (d/2)² × 10⁻⁶ × length × density × quantity — so you can verify or replicate the calculation manually.

Round Bar Weight Calculation Formula

The fundamental formula and how it works

Weight (kg) = π × (d/2)² × 10⁻⁶ × L × ρ × Q

d = diameter (mm) · π × (d/2)² = cross-section area (mm²) · 10⁻⁶ converts mm² → m² · L = length (m) · ρ = density (kg/m³) · Q = quantity

Worked Example:

A 10 mm MS round bar, 1 meter long, quantity 1:

Radius = 10 ÷ 2 = 5 mm
Cross-section area = π × 5² = 78.54 mm²
Weight = 78.54 × 10⁻⁶ × 1 × 7,850 × 1
Weight = 0.617 kg (or 1.36 lb)

Example Calculations

Real-world round bar weight examples for common materials and sizes

10 mm MS Round Bar, 1 m

Diameter 10 mm · Length 1 m

Mild Steel (7,850 kg/m³)

0.617 kg/m · 0.414 lb/ft

Result

0.617 kg

25 mm Aluminum Round Bar, 2 m

Diameter 25 mm · Length 2 m

Aluminum (2,700 kg/m³)

1.326 kg/m · 0.891 lb/ft

Result

2.651 kg

1/2 in Brass Round Bar, 3 ft

Diameter 0.5 in · Length 3 ft

Brass (8,530 kg/m³)

0.727 lb/ft · 1.082 kg/m

Result

2.18 lb

40 mm SS 304 Round Bar, 1.5 m

Diameter 40 mm · Length 1.5 m

Stainless Steel SS 304 (8,000 kg/m³)

10.053 kg/m · 6.756 lb/ft

Result

15.08 kg

Material Densities for Round Bar Weight

Standard density values for common round bar materials

Material	Density (kg/m³)	Common Use
Mild Steel (MS)	7,850	General construction, fabrication, structural
Stainless Steel (SS 304)	8,000	Corrosion-resistant, food grade, medical
EN8 Steel	7,850	Medium carbon steel, shafts, axles, studs
Aluminum	2,700	Lightweight, aerospace, automotive, frames
Brass	8,530	Decorative, plumbing fittings, electrical
Copper	8,960	Electrical conductors, busbars, plumbing

Tips for Accurate Round Bar Weight Estimation

Practical advice for getting the most accurate weight estimates

For MS round bars, always confirm whether you need theoretical weight or actual weight. Indian standard IS 1731 allows a ±3% tolerance on actual weight vs theoretical weight for hot-rolled round bars.

Aluminum is about 65% lighter than mild steel (2,700 vs 7,850 kg/m³). If you're substituting aluminum for steel, the same diameter will weigh roughly one-third as much — critical for weight-sensitive applications.

Stainless steel (SS 304) is approximately 2% heavier than mild steel. For a 100 kg MS order, the SS equivalent would be about 102 kg — important for procurement and cost estimation.

For galvanized round bars, the zinc coating adds negligible weight (typically less than 0.5%). Use the base steel density for estimates — the coating weight is within manufacturing tolerance.

Common Mistakes to Avoid

Don't let these errors cost you time and money

Confusing diameter with radius

The calculator uses the diameter (full width of the round bar). The cross-section area formula is π × (d/2)² = π × r². If you enter the radius instead of the diameter, your calculated weight will be only 25% of the actual weight — a dangerous error for procurement.

Mixing metric and imperial units

A 10 mm diameter and a 1 inch diameter give very different results (1 in = 25.4 mm, so the 1 in bar has 6.45× more cross-section area). Always verify your unit system before entering dimensions.

Assuming all steel has the same density

Mild steel (7,850 kg/m³), stainless steel (8,000 kg/m³), and EN8 (7,850 kg/m³) have different densities. SS 304 is about 2% heavier than MS for the same dimensions — significant for large orders.

Forgetting to multiply by quantity

The weight shown is for the entered quantity. If you need 50 bars, set quantity to 50 — don't manually multiply, or you risk calculation errors on large orders.

Frequently Asked Questions

Common questions about round bar weight calculation

Multiply the cross-section area (π × (diameter/2)²) by the length and material density. Formula: Weight (kg) = π × (d/2)² × 10⁻⁶ × Length (m) × Density (kg/m³) × Quantity. For example, a 10 mm MS round bar, 1 meter long: Radius = 5 mm, Area = π × 5² = 78.54 mm², Weight = 78.54 × 10⁻⁶ × 1 × 7,850 = 0.617 kg. Use the calculator above — select your material, enter diameter and length, and get instant results in kg and lb.

The standard formula is: Weight (kg) = π × (d/2)² × 10⁻⁶ × L × ρ × Q, where d = diameter in mm, L = length in meters, ρ = material density in kg/m³, and Q = quantity. For mild steel (MS), a simplified version is: Weight (kg) = d² (mm) × Length (m) × 0.006165. The factor 0.006165 comes from: π/4 × density × 10⁻⁶ = 0.7854 × 7,850 × 10⁻⁶ ≈ 0.006165. For imperial: Weight (lb) = d² (in) × Length (ft) × 2.67 (for mild steel).

For mild steel (MS) round bars, use the simplified formula: Weight (kg) = d² (mm) × Length (m) × 0.006165. Example: a 12 mm MS round bar, 6 meters long → 144 × 6 × 0.006165 = 5.33 kg. Common weights per meter for MS round bars: 8 mm = 0.395 kg/m, 10 mm = 0.617 kg/m, 12 mm = 0.888 kg/m, 16 mm = 1.58 kg/m, 20 mm = 2.47 kg/m, 25 mm = 3.85 kg/m. Select 'Mild Steel (MS)' in the calculator to get instant results for any diameter.

Stainless steel (SS 304) round bar weight uses the same formula but with a density of 8,000 kg/m³. Simplified SS formula: Weight (kg) = d² (mm) × Length (m) × 0.00628. Example: a 20 mm SS 304 round bar, 3 meters long → 400 × 3 × 0.00628 = 7.54 kg. SS 304 is about 1.9% heavier than mild steel for the same dimensions. Select 'Stainless Steel (SS 304)' from the material dropdown in the calculator above.

To calculate round bar weight in kg: (1) Square the diameter in mm (d²), (2) Multiply by 0.7854 (π/4) to get cross-section area in mm², (3) Multiply by 10⁻⁶ to convert to m², (4) Multiply by length in meters, (5) Multiply by density in kg/m³ (7,850 for MS), (6) Multiply by quantity. Or simply use the calculator above — enter your diameter, length, select material, and get the weight in kg instantly with no manual math.

For the same width/diameter, a square bar weighs about 27.3% more than a round bar. This is because: Square area = d², Round area = π × (d/2)² = π/4 × d² ≈ 0.7854 × d². Ratio = 1 / 0.7854 = 1.273. Example: a 10 mm MS round bar weighs 0.617 kg/m, while a 10 mm MS square bar weighs 0.785 kg/m. Use the Square Bar Weight Calculator for square sections and this calculator for round sections.

Aluminum round bar weight uses the same formula but with aluminum's lower density of 2,700 kg/m³. Simplified formula: Weight (kg) = d² (mm) × Length (m) × 0.00212. Example: a 25 mm aluminum round bar, 2 meters long → 625 × 2 × 0.00212 = 2.65 kg. Aluminum is about 65% lighter than mild steel — the same diameter in aluminum weighs roughly one-third of the steel equivalent. Select 'Aluminum' from the material dropdown above.

MS round bars (also called MS rods) in India are commonly available from 6 mm to 80 mm diameter, with standard lengths of 6 meters or 12 meters. Common sizes include: 6 mm, 8 mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 32 mm, 40 mm, 50 mm, 63 mm, 75 mm, and 80 mm. These are manufactured as per IS 1731 standards (hot-rolled) and IS 2062 (cold-drawn). The calculator works with any diameter — enter your exact size.

Yes, this calculator supports brass (8,530 kg/m³) and copper (8,960 kg/m³) round bars. Simply select 'Brass' or 'Copper' from the material dropdown. Brass is about 8.7% heavier than mild steel for the same diameter, and copper is about 14.1% heavier. Example: a 10 mm copper round bar, 1 m long = 0.704 kg (vs 0.617 kg for MS). The calculator also works with any custom density for unlisted materials like gunmetal, phosphor bronze, or engineering plastics.

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Last updated May 23, 2026

Round Bar Weight Calculator

Weight Breakdown

Formula Used

How to Use the Round Bar Weight Calculator

Select Material

Enter Dimensions & Quantity

Review the Results

Use the Formula Reference

Round Bar Weight Calculation Formula

Example Calculations

Material Densities for Round Bar Weight

Tips for Accurate Round Bar Weight Estimation

Common Mistakes to Avoid

Frequently Asked Questions

Embed Round Bar Weight Calculator

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