Concrete

Rebar Grid Spacing and Linear Feet

A rebar grid is best counted by direction. Determine how many bar lines cross the slab at the selected spacing, multiply each set by its run length, then add laps or stock-length effects separately.

QUICK ANSWER

The short version

Count rebar grid lines separately in both directions from the specified spacing, multiply each count by its bar run, then add project-defined laps, hooks, and stock-length effects. Use published unit weights only when converting length to weight.

QUICK CHECKLIST

Five checks before trusting an estimate

  • For a rectangular grid, spacing across one dimension determines the number of bars running in the other direction.
  • Multiply bar count by the required bar run after edge conditions are defined.
  • Required lap lengths and splice locations are design-dependent and can materially increase linear footage.
  • When converting linear feet to weight, use the published unit weight for the exact bar size.
  • Spacing, cover, development, hooks, chairs, and bar grade are not quantity defaults.
PUBLISHING INFO

About this guide

Published: September 18, 2026

Last reviewed: September 18, 2026

Published by BuildYard. The guide reflects BuildYard's calculation methodology and editorial standards and does not replace project-specific professional advice.

Count bars in each direction

For a rectangular grid, spacing across one dimension determines the number of bars running in the other direction.

Treat longitudinal and transverse sets separately so spacing changes remain auditable.

Use actual run lengths

Multiply bar count by the required bar run after edge conditions are defined.

Keep the assumption visible so it can be replaced when project or product data is available.

Handle laps and stock lengths separately

Required lap lengths and splice locations are design-dependent and can materially increase linear footage.

Convert total required runs into available stock bars only after the reinforcement layout is known.

Use published bar properties

When converting linear feet to weight, use the published unit weight for the exact bar size.

Do not infer structural adequacy from takeoff weight.

Follow the reinforcement design

Spacing, cover, development, hooks, chairs, and bar grade are not quantity defaults.

Use the project reinforcement details and applicable design requirements.

BUILDYARD REFERENCE EXAMPLE

20 × 12 ft slab with bars at 12 in on center

BuildYard geometric example before cover, laps, hooks, chairs, or structural-design adjustments.

Grid componentResult
Bars running 20 ft13 bars / 260 lin ft
Bars running 12 ft21 bars / 252 lin ft
Net grid length512 lin ft
With 5% cutting allowance537.6 lin ft
SOURCE NOTES

References used for this guide

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Use project-specific information first

Current manufacturer data, supplier specifications, drawings, field measurements, applicable codes, permit requirements, and qualified professional guidance can take priority over a general-purpose planning estimate.