# Complete works of steel weight calculation formula in kg

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As the calculation formula of steel or non-ferrous metal weight that the engineer should know. Today we sorted them out and hope to collect them. The formula for calculating weight is different for different steels in kg.

## 1、 Concept of theoretical weight of steel

The theoretical weight of steel is based on the nominal size and density of steel (formerly called specific gravity) the calculated weight is called the theoretical weight. This is directly related to the allowable deviation of steel length, section area and size. Due to the allowable deviation of steel in the manufacturing process, the theoretical weight calculated by the formula is different from the actual weight, so it is only used as a reference for estimation.

## 2、 Calculation formula of theoretical weight of steel

The unit of measurement for the theoretical weight of steel is kilogram (kg). The basic formula is:

W (weight kg) = f (sectional area mm2) × L (length m) ×ρ (density g / cm3) × 1/1000

Density of steel ρ It is 7.85g/cm3, and the calculation formula of theoretical weight of various steels is as follows:

Variety name: round steel / wire rod

Calculation unit: kg / M

Calculation formula: w = 0.006165 × d2

Formula Description: D = diameter mm,

Calculation example: for round steel with diameter of 100mm, calculate the weight per M. Weight per M = 0.006165 × 1002=61.65kg

Variety name: deformed steel bar

Calculation unit: kg / M

Calculation formula: w = 0.00617 × d2

Formula Description: D = section diameter mm

Calculation example: for deformed steel bar with section diameter of 12mm, calculate the weight per M. Weight per M = 0.00617 × 122≈0.89kg

### Variety name: Weight calculation formula of square steel

Calculation unit: kg / M

Calculation formula: w = 0.00785 × a2

Formula Description: a = side width mm

Calculation example: for square steel with side width of 20mm, calculate the weight per M. Weight per M = 0.00785 × 202=3.14kg

Variety name: flat steel

Calculation unit: kg / M

Calculation formula: w = 0.00785 × b × d

Formula Description: B = side width, d = thickness, mm

Calculation example: calculate the weight per m of flat steel with side width of 40mm and thickness of 5mm. Weight per M = 0.00785 × forty × 5=1.57kg

### Variety name: Weight calculation formula of hexagonal angle steel

Calculation unit: kg / M

Calculation formula: w = 0.006798 × s2

Formula Description: S = opposite edge distance mm

Calculation example: calculate the weight per m of hexagonal angle steel with a distance of 50mm from the opposite side. Weight per M = 0.006798 × 502=16.995kg

### Variety name: calculation formula of octagonal steel

Calculation unit: kg / M

Calculation formula: w = 0.0065 × s2

Formula Description: S = opposite edge distance mm

Calculation example: calculate the weight per m of octagonal steel with a distance of 80mm from the opposite side. Weight per M = 0.0065 × 802=41.6kg

### Variety name: calculation formula of equilateral angle steel

Calculation unit: kg / M

Calculation formula: w = 0.00785 × [d（2b–d）+0.215（R2–2r2）]

Formula Description: B = edge width, d = edge thickness, r = inner arc radius, r = end arc radius (outer arc)

Calculation example: 20mm × Weight per m of 4mm equilateral angle steel. 4mm from metallurgical product catalogue × If r of 20mm equilateral angle steel is 3.5 and R is 1.2, then weight per M = 0.00785 × [4 × （2 × 20–4）+0.215 × （3.52–2 × 1.22）]=1.15kg

### Variety name: calculation formula of unequal angle steel

Calculation unit: kg / M

Calculation formula: w = 0.00785 × [d（B+b–d）+0.215（R2–2r2）]

Formula Description: B = long side width, B = short side width, d = side thickness, r = inner arc radius, r = end arc radius

Calculation example: 30mm × 20mm × Weight per m of 4mm unequal angle steel. Find out 30 from the catalogue of metallurgical products × twenty × 4. If r of unequal angle steel is 3.5 and R is 1.2, weight per M = 0.00785 × [4 × （30+20–4）+0.215 × （3.52–2 × 1.22）]=1.46kg

### Variety name: channel steel calculation formula

Calculation unit: kg / M

Calculation formula: w = 0.00785 × [hd+2t（b–d）+0.349（R2–r2）]

Formula Description: H = height, B = leg length, d = waist thickness, t = average leg thickness, r = inner arc radius, r = end arc radius

Calculation example: 80mm × 43mm × Weight per m of 5mm channel steel. It is found from the metallurgical product catalogue that the channel steel t is 8, R is 8 and R is 4, then the weight per M = 0.00785 × [80 × 5+2 × eight × （43–5）+0.349 × （82–42）]=8.04kg

### Variety name: calculation formula of H-section steel

Calculation unit: kg / M

Calculation formula: w = 0.00785 × [hd+2t（b–d）+0.615（R2–r2）]

Formula Description: H = height, B = leg length, d = waist thickness, t = average leg thickness, r = inner arc radius, r = end arc radius

Calculation example: 250mm × 118mm × 10mm I-beam weight per M. It is found from the metal material manual that if the I-beam t is 13, R is 10 and R is 5, the weight per M = 0.00785 × [250 × 10+2 × thirteen × （118–10）+0.615 × （102–52）]=42.03kg

### Variety name: steel plate calculation formula

Calculation unit: kg / m2

Calculation formula: w = 7.85 × d

Formula Description: D = thickness

Calculation example: for steel plate with thickness of 4mm, calculate the weight per m2. Weight per m2 = 7.85 × 4=31.4kg

### Variety name: steel pipe (including seamless steel pipe and welding)

Calculation unit: kg / M

Calculation formula: w = 0.02466 × S（D–S）

Formula Description: D = outer diameter, s = wall thickness

Calculation example: for seamless steel pipe with outer diameter of 60mm and wall thickness of 4mm, calculate the weight per M. Weight per M = 0.02466 × four × （60–4）=5.52kg

## 3、 Weight calculation formula of other non-ferrous metals

Other non-ferrous metals include brass plate, copper plate, zinc plate and lead plate. The weight is calculated as follows:

Calculation method: specific gravity × Thickness = weight per square meter (brass plate: specific gravity 8.5; copper plate: specific gravity 8.9; zinc plate: specific gravity 7.2; lead plate: specific gravity 11.37)

### Calculation formula of brass tube weight

Formula: (outer diameter - wall thickness) × thick × zero point zero two six seven × Length m

Example: brass tube 20mm × 1.5mm thick × 6m (length)

Calculation: (20-1.5) × one point five × zero point zero two six seven × 6=4.446kg

### Weight calculation formula of red copper pipe

Formula: (outer diameter - wall thickness) × thick × zero point zero two seven nine six × Length m

Example: red copper pipe 20mm × 1.5mm thick × 6m (length)

Calculation: (20-1.5) × one point five × zero point zero two seven nine six × 6=4.655kg

### Weight calculation formula of aluminum flower plate

Formula: length m × Width m × Thickness mm × two point nine six

Example: aluminum flower plate 1m wide × 3M long × 2.5mm thick

Calculation: 1 × three × two point five × 2.96=22.2kg

Knowing the calculation formula of the weight of these steels, I hope it will be helpful to your engineers.