Rebar Quantity Estimator
Floor area × steel rate for early-stage estimation.
Inputs
Result
Formula
| Total = floor area × steel rate × seismic factor | |
| Rate by structural system (kg/m²) | ranges above |
| Seismic factor 6/7/8/9 | 0.95 / 1.00 / 1.08 / 1.15 |
| Cost = quantity × unit price |
10,000 m² frame at intensity 7: rate 45-62 kg/m², mid 53.5, giving 535 t; at 4200 CNY/t that is about 2.25 million CNY. At intensity 8 the 1.08 factor lifts it to 578 t.
FAQ
How accurate is this?
Usually within ±15% at concept stage - fine for investment estimates and option comparison, never for settlement or cutting lists. The biggest error sources are basement depth (each level adds 10-20 kg/m² to the building average) and span (large span/depth ratios push beam steel up sharply).
Why does a shear wall building use more steel than a frame?
The walls themselves have low ratios, but there are many of them with dense boundary elements (concealed and end columns) carrying plenty of detailing steel, and shear wall buildings are usually taller, raising slab and coupling beam reinforcement. Frames have fewer walls and more open space. Shear walls save formwork and time, not steel.
How much does HRB400 save over HRB335?
Theoretically about 20% by strength, in practice 10-15% because minimum ratios and detailing govern. With a price gap of only 100-200 CNY/t it still pays, which is why HRB400 dominates. But crack width and deflection can become critical, so it is not a simple substitution.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.