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Calculators / Construction / Rebar grid
Rebar grid calculator
Estimate reinforcing-bar length for a rectangular two-direction grid.
On this page
Bars running lengthwise26bars
Bars running widthwise41bars
Total rebar length454.3m
Calculator controls
How to calculate
Estimate reinforcing-bar length for a rectangular two-direction grid.
bar count = floor(cross dimension ÷ spacing) + 1
Worked example
Slab length (m): 8; Slab width (m): 5; Bar spacing (mm): 200; Grid layers: 1; Lap and waste (%): 10.
Bars running lengthwise: 26 bars; Bars running widthwise: 41 bars; Total rebar length: 454.3 m.
Assumptions and limits
Engineering drawings control bar diameter, cover, anchorage, laps, openings, supports, and reinforcement arrangement.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate reinforcing-bar length for a rectangular two-direction grid. Every assumption remains visible so the result can be checked or changed.
When this tool is useful
Use the rebar grid for an initial estimate, comparison, or classroom calculation.
Understanding your inputs
| Input | What to enter |
|---|---|
| Slab length (m) | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Slab width (m) | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Bar spacing (mm) | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Grid layers | Enter a number of at least 1 and no more than 10. |
| Lap and waste (%) | Enter a number of at least 0 and no more than 100. |
Frequently asked questions
What are the limits of this rebar grid?
Engineering drawings control bar diameter, cover, anchorage, laps, openings, supports, and reinforcement arrangement.
Can I use different units?
Use the units printed beside each field. Convert measurements first when your source uses different units.