Free · Construction materials calculators 🧱

Rectangular Rebar Grid Length & Stock Lower Bound

Estimate two-direction rebar grid length from slab dimensions, edge offsets and maximum spacing, with a clearly labeled stock-length lower bound.

  • Formula & worked example
  • Private in your browser
  • No signup
Go to tool

Calculator inputs

Loading calculator…

How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A 5 × 4 m slab with 10 cm edge offsets and 40 cm spacing has a 4.8 × 3.8 m grid. The model gives 13 crosswise and 11 lengthwise bars totaling 102.2 m.

Grid dimensions = slab dimensions − 2 × edge offset; bars = ceil(grid dimension / spacing + 1); stock lower bound = ceil(total bar length / stock length)

Worked example

Enter these known values and leave the other values blank.

Length
5 m
Width
4 m
Edge-to-bar-line offset
10 cm
Maximum spacing between bar lines
40 cm
Available stock length
6 m
Price per unit of stock length
2 USD / m
Price per stock piece
12 USD
Grid length
4.8 m
Grid width
3.8 m
Total grid bar length
102.2 m
Stock count: length-only lower bound
18
Material cost at the stock lower bound
216 USD

Assumptions and limitations

  • The model places a bar line at each edge of the inner rectangular grid and uses spacing no greater than the entered maximum. Edge offset is measured to those bar lines; bar diameter is not included.
  • The stock count divides total required length by stock length and rounds up. It is a lower bound, not a feasible cutting or purchasing schedule. Offcuts, individual cut lengths, overlaps, bends and waste can require more stock.
  • For the worked example, 18 six-meter stock pieces is the length-only bound. Obtaining 13 unspliced 3.8 m bars and 11 unspliced 4.8 m bars actually needs 24 six-meter pieces when each stock piece supplies only one required bar.
  • Material cost multiplies the lower-bound stock count by stock-piece price. It excludes ties, labor, delivery, tax and other supplies. Currency conversions use captured rates, with their date shown.
  • This is a quantity model. It does not select structural reinforcement size, spacing, cover or splice requirements. Enter the dimensions and spacing required by the project design.

Common questions

Can I order the displayed minimum stock count?

First make a cutting and splice plan. Total-length division can underestimate purchasable stock even after rounding, because unused offcuts may not fit the remaining required lengths.

References

Bookify accepts zero edge offset and zero prices while retaining positive grid dimensions, spacing and stock lengths.

Explore construction materials calculators 🧱 or browse all construction calculators.