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Rebar Quantity Estimator

Floor area × steel rate for early-stage estimation.

Quick answer

With the default inputs: Floor area 10000 m² · Structural system Frame · Seismic intensity 7 etc.Estimated rebar (mid) 535.0 t

Edit the inputs below to recalculate.

Inputs

m²
CNY/t

Result

Estimated rebar (mid)
535.0t
Steel rate45~62kg/m²
Seismic factor1.00
Adjusted rate45~62kg/m²
Low estimate450.0t
Mid estimate535.0t
High estimate620.0t
Mid rebar cost224.710k CNY

Steel rates are statistical ranges from built projects, not code values: masonry 30-42, frame 45-62, frame-shear 55-78, shear wall 58-85, basement/civil defence 95-140 kg/m². Real content depends on span, storey count, loading, basement depth, transfer levels, seismic class and steel grade (HRB400 saves 10-15% over HRB335). Use these for concept-stage comparison only; after preliminary design, take quantities from the reinforcement drawings. For tendering, bias upward.

Formula

Total = floor area × steel rate × seismic factor
Rate by structural system (kg/m²)ranges above
Seismic factor 6/7/8/90.95 / 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.

How to work it out

  1. Pick a steel intensity for the structural form (kg/m²): 25-35 for masonry, 45-65 for frames, 55-75 for frame-shear wall, 60-85 for shear wall.
  2. Adjust for seismic intensity: ×0.95 at 6, ×1.00 at 7, ×1.08 at 8, ×1.15 at 9.
  3. Total = floor area × intensity × seismic factor.
  4. Cost = tonnage × all-in rate (4,200-5,000 per tonne including fabrication, fixing and waste).
  5. Cross-check by element at scheme stage: foundations 20-25%, superstructure 55-65%, secondary structure 10-15%.

Where it goes wrong

Material and cost

Steel intensity is the most sensitive cost driver in housing. The gap between 45 and 55 kg/m² is 45 million in material on a 100,000 m² project at 4,500 per tonne. Structural selection at scheme stage therefore matters far more than saving steel during construction.

On site

Basis

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.

Cite this page

Use this format in reports, method statements or coursework. The link is permanent.

Building Calculator. Rebar Quantity Estimator. 2026-10-25. https://jianzhujisuan.com/en/rebar-total-estimate

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.