Rebar Weight Calculator Online

Rebar weight calculation sits behind almost every structural estimate an engineer produces — bar bending schedules, bill of quantities, steel procurement orders, and site wastage checks all trace back to one simple formula. Get it wrong on a large residential or industrial job, and the error compounds fast: a 2% miscalculation on a multi-storey building's reinforcement can mean tonnes of steel over- or under-ordered. This guide walks through the formula itself, where it comes from, how it's applied under both metric (ISO/BNBC) and US customary (ASTM) conventions, and three worked examples pulled from typical Bangladeshi construction scenarios.

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Rebar Weight Calculator

IS 1786-based unit weight reference — multiple bar sizes, meter/feet input, instant kg / ton / lb totals

Dia (mm)	Qty	Length	Unit	Weight per Bar (kg)	Row Total (kg)

Total Weight (All Rebars)

Total (kg) 0.000

Total (lb) 0.000

Total (Metric Ton) 0.000000

Total (Quintal) 0.00000

Formula (IS 1786): W = d² / 162  kg/m, where d = bar diameter in mm.
1 kg = 2.20462 lb  |  1 metric ton = 1000 kg  |  1 quintal = 100 kg

Downloads the results as an Excel (.xls) file to your device.

Tool: Rebar Weight Calculator Ref: IS 1786 www.bnfel.com

Rebar Weight Calculator Formula

If you'd rather skip the arithmetic, our Rebar Weight Calculator automates everything below — select a bar size, enter length and quantity, and it returns weight in kg, metric ton, and pounds instantly.

The standard rebar weight formula

Reinforcement bars are manufactured to a consistent density, so their weight per unit length can be derived directly from the bar's nominal diameter without needing to weigh anything. Starting from the basic mass equation for a cylinder:

W = (π/4) × d² × ρ × L

where d is the bar diameter in meters, ρ is the density of steel (7850 kg/m³), and L is the bar length in meters. When diameter is expressed in millimeters instead of meters, the constants collapse into the simplified form structural engineers use on site:

W (kg/m) = d² ÷ 162

This is the formula referenced across ISO 6935-covered reinforcement standards and is the basis BNBC 2020 (Part 6, structural design provisions) assumes when specifying reinforcement quantities and detailing schedules. It applies to deformed bars at their nominal diameter — the manufactured rib profile adds a small tolerance that doesn't materially affect the calculated weight for estimating purposes.