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/// Grid length and stock pieces

Rebar Calculator

Use the rebar calculator to count grid runs across both slab directions, total their lineal length, apply layers and waste, and round into whole entered stock lengths. This is a quantity takeoff from user-provided spacing, not reinforcement design. Bar size, spacing, laps, cover, supports, development, loads, and code compliance require approved documents.

Content reviewed Jul 16, 2026 · Source records reviewed through Jul 15, 2026

01

Slab grid and stock length

Enter spacing and layers only from an approved project requirement. ProjectQty calculates quantity but does not choose reinforcement.

ftExample starting measurement — replace it with your field measurement.
ftExample starting measurement — replace it with your field measurement.
inRequired — enter a project-specific planning value and verify it before ordering. ProjectQty does not apply an unsupported default.Spacing must be greater than zero.
layersExample starting value — replace it with the project or product value.
ftRequired — enter the value from the exact product label or current technical sheet. ProjectQty does not guess this value.Stock Length must be greater than zero.
%Required — enter a project-specific planning value and verify it before ordering. ProjectQty does not apply an unsupported default.
USDOptional — enter your current local price per stock length.
View current estimate

/// Answer-first planning notes

How much rebar length follows from my entered grid spacing?

How much rebar length follows from my entered grid spacing checkpoints
Planning inputCalculation roleField check
Slab dimensionsSet each grid run lengthUse the reinforcement boundary
Entered spacing and layersCount runs and total lengthCopy approved design values
Stock length and wasteRound to purchasable barsPlan laps and cuts separately

/// Formula & field notes

How this rebar estimate works

FormulaGrid length = bars across width × slab length + bars across length × slab width, multiplied by layers and waste.

Worked example

A 10 ft × 10 ft grid at 12 in spacing has 11 runs each direction; with 10% waste it needs 242 ft, or 13 twenty-foot stock lengths.

/// Source trail

Data & assumptions

Every source has a declared scope. A reference can support a conversion or product assumption without turning this estimate into a supplier quote.

National Institute of Standards and Technology · Primary evidenceNIST Guide to the SI, Appendix B: Conversion Factors

Exact international-foot to meter conversion; U.S. survey-foot conversion is explicitly outside this claim.

Effective 2025-08-18 · Reviewed 2026-07-15 · Next review 2027-07-15
NOAA National Geodetic Survey · Prequalified fallbackThe DSDATA Format, Appendix D: U.S. Survey Foot vs International Foot

Independent confirmation that one international foot equals exactly 0.3048 meters; U.S. survey-foot conversion remains distinct.

Effective 2025-06-10 · Reviewed 2026-07-15 · Next review 2027-07-15

/// Common questions

Rebar calculator FAQ

What should I verify before ordering rebar?

Confirm field dimensions and approved grid spacing, layers, lap allowance, and stock length against the exact product or supplier information. ProjectQty shows the assumptions so you can replace planning defaults before ordering stock lengths.

How does waste affect the rebar estimate?

Waste is applied after the base geometry is calculated and before discrete packages or pieces are rounded up. Use a higher allowance for complex layouts, cuts, pattern matching, breakage, or uncertain field dimensions.

Is this rebar result a professional design?

No. It is a quantity-planning result. The result is not a reinforcement schedule and cannot establish structural capacity or code compliance.

/// Keep planning

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