Beam Weight Calculator
Estimate the self-weight of a rectangular reinforced-concrete beam from its length, width and depth in metres plus a concrete density in kg/m³. The density field opens at 2400 kg/m³ for normal reinforced concrete, and the output in kilograms feeds directly into dead-load and lifting estimates.
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Beam Weight Calculator online
Estimate the self-weight of a rectangular concrete beam from its length, section width and depth and the concrete density — for formwork design, lifting checks and early load take-downs.
How it works
The beam is treated as a solid cuboid: weight = length(m) × width(m) × depth(m) × density(kg/m³). The first three inputs give the concrete volume in cubic metres; multiplying by density converts that volume to mass. The 2400 kg/m³ default represents plain concrete plus the embedded reinforcement; use 2500 if your specification calls for heavily reinforced or dense-aggregate concrete.
Worked example
A beam 5 m long, 0.3 m wide and 0.5 m deep at 2400 kg/m³: volume = 5 × 0.3 × 0.5 = 0.75 m³. Weight = 0.75 × 2400 = 1800 kg (1.8 t). A shorter 3 m beam of 0.25 m × 0.4 m section: volume = 3 × 0.25 × 0.4 = 0.30 m³, weight = 0.30 × 2400 = 720 kg.
Units
All dimensions are in metres; a 300 mm width must be entered as 0.3. Output is in kilograms — divide by 1000 for tonnes or by 9.81 for kilonewtons of dead load (1800 kg ≈ 17.66 kN).
Practical tips
- Measure depth to the full structural section, including any upstand or downstand, not just the visible face below the slab.
- For a run of identical beams, compute one beam and multiply by the count rather than entering the total length, so a mid-project section change only affects one line.
- If the beam is composite with a slab flange (T-beam), calculate the rectangular stem here and the flange slab separately to avoid double-counting the overlap.
- This is a self-weight quantity for planning; span capacity, shear, deflection and support design must be verified against the drawings by a licensed engineer.
Edge cases and limitations
- Flanged beams are not one rectangle. A T-beam cast with its slab has a flange the simple section ignores. Price it as two boxes: a 1.2 m × 0.15 m flange over a 0.3 m × 0.35 m web, 5 m long, is (1.2 × 0.15 + 0.3 × 0.35) × 5 = 1.425 m³ ≈ 3,420 kg — nearly double the 1,800 kg of the plain 300 × 500 section. When the flange is real, add it.
- 2400 or 2500? The 2,400 kg/m³ default is plain concrete. Design codes commonly use 2,500 kg/m³ for reinforced concrete to cover the steel; switching raises every result by about 4%. Match the value your structural engineer is using.
- Haunches and tapers. A haunched beam end adds a triangular wedge: ½ × haunch length × extra depth × width, times density. Small on paper — a 1 m haunch deepening the beam by 0.3 m adds about 108 kg on a 0.3 m wide beam.
- Self-weight only. The result excludes finishes, supported slab loads and anything the beam carries. It is the starting line of a load take-down, not the total design load.
Privacy and browser processing
The calculation runs entirely in your browser — your dimensions are never uploaded.
Frequently asked questions
What density should I enter for a normal concrete beam?
Keep the 2400 kg/m³ default for ordinary reinforced concrete. Use 2300 for plain unreinforced concrete or 2500 for heavily reinforced or dense-aggregate members, and check the project specification if one is stated.
How heavy is a 5 m beam of 300 × 500 mm section?
Volume = 5 × 0.3 × 0.5 = 0.75 m³, and 0.75 × 2400 = 1800 kg, about 1.8 tonnes or 17.7 kN of dead load.
Do I enter beam dimensions in mm or metres?
Metres. Entering 300 instead of 0.3 for the width inflates the volume a thousandfold, so convert first: 300 mm = 0.3 m, 500 mm = 0.5 m.
Does the result include the reinforcement weight separately?
No separate bar schedule is needed. The 2400 kg/m³ default already allows for typical reinforcement content; only for unusually congested cages would you raise the density toward 2500 kg/m³.