Rebar Grid Quantity Calculator
Estimate bar lines in a simple two-direction grid. This is a purchasing sketch, not a reinforcement design.
Spacing and edge inset are inputs from your plan. No bar size or structural load is selected here.
How the calculation works
Clear length and width equal overall dimensions minus two edge insets. Number of bars parallel to length = ceil(clear width ÷ spacing) + 1; bars parallel to width = ceil(clear length ÷ spacing) + 1. Linear feet = each count × its clear bar length.
Worked example
For a 20 × 10 ft grid, 12 in maximum spacing and 3 in edge inset, estimate 11 lengthwise lines and 21 widthwise lines. That totals about 414 linear feet. With 10% extra, a simple length division suggests 23 stock bars at 20 ft each.
Before you order
Stock-bar count is only linear feet divided by bar length. Cutting layout, lap splices, hooks, supports, openings and structural requirements can increase it. Have the bar schedule and placement checked against plans.
Review the calculation method and source notes, then use the supplier checklist before placing an order.
How to interpret the bar count
The tool counts straight grid lines in two directions after subtracting the edge inset. It then totals their clear lengths, adds your allowance and divides by stock-bar length for an approximate purchase count. It does not calculate lap splice requirements, cutting waste by piece, chairs or vertical bars.
For example, a 10 × 10 ft slab with a 3 in edge inset leaves 9.5 ft of clear length in each direction. At 12 in maximum spacing, each direction needs 11 grid lines, so the straight grid contains about 209 linear ft before allowance. Layout and reinforcement size must follow project documents.
Questions before you order
Does the stock bar count include lap splices?
No. It divides total linear feet by stock length. Add splice and cut planning separately.
Is the spacing a structural recommendation?
No. It is an input for estimating quantity, not a design recommendation.
Does the tool count chairs or tie wire?
No. It estimates straight rebar only.
Continue planning
Content and calculator by pourmeasure. Formula and assumption notes: methodology and sources. Updated October 2026. No independent engineering review is claimed.