Steel Bar (Sarya) Weight Calculator
Find the weight of steel reinforcement bars from their size, length and number, and what they cost by the kilogram.
Total weight
541.2 kg (0.541 tonnes)
- One bar
- 10.82 kg
- Per metre
- 0.888 kg (0.271 kg per ft)
50 bars of 12 mm, 40 ft long, weigh about 541.2 kg.
How it's worked out
- Weight per metre
12² ÷ 162.20.888 kg - One bar
0.888 kg × 12.192 m10.82 kg - All bars
10.82 kg × 50541.2 kg
- Uses the standard density of steel, 7,850 kg/m³. Real bars can be a few percent lighter or heavier within the allowed tolerance.
The formula
kg per metre = d² ÷ 162.2 (d in mm)
It comes from the bar's cross-section, π/4 × d², times the density of steel, 7,850 kg/m³.
Worked example
50 bars of 12 mm, each 40 ft (12.19 m) long: 0.888 kg × 12.19 m = 10.82 kg a bar, so 541.2 kg in all.
Questions people ask
What is the formula for steel bar weight?
Weight in kg per metre = diameter in mm² ÷ 162.2. A 12 mm bar weighs 144 ÷ 162.2 = 0.888 kg a metre.
How much does a 40-foot 12 mm bar weigh?
About 10.8 kg (12.19 m × 0.888 kg). A 40-foot 16 mm bar weighs about 19.2 kg.
What do #3, #4 and #5 bars mean?
The number is the diameter in eighths of an inch: #3 is 3/8" (about 10 mm), #4 is 1/2" (12 mm) and #5 is 5/8" (16 mm).
About this calculator
Formula and rules last checked 25 October 2026Written and tested by the CalculatorDex teamReport a problem