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Rebar Quantity Calculator

Count a user-defined reinforcement grid, stock bars, cut length and approximate steel mass.

Your numbers

Make it your own
Updates as you type
Conservative stock bars to order
22stock bars

Calculated from your inputs · rounded for display

Bars running along length11
Bars running along width21
Total cut length419.3333ft
Steel mass at 7,850 kg/m³113.474kg

Quantity and mass only for a single rectangular grid. You choose spacing, diameter, cover and stock length. No load design, anchorage, laps, hooks or compliance determination.

Your calculation, step by step

No black boxes
  1. Net grid dimensions subtract cover from both ends. Counts = ceil(perpendicular span / maximum spacing) + 1.
  2. Cut the two orientations in separate stock batches; round up stock counts. No cross-batch offcut reuse is assumed.

What if things were different?

Save up to three scenarios, then change your inputs to compare the possibilities.

How to use this calculator

  1. Enter your own values in the labeled fields. Check the units and assumptions before comparing results. Only the fields needed for your selected calculation mode are shown.
  2. Your answer updates automatically. Review the calculation steps to see exactly how it was calculated.
  3. Copy, share, save, or download your result. Saved inputs stay on this device.

How the calculation works

Bars per direction=ceil(net perpendicular span/spacing)+1; mass=length × πd²/4 × density

Spacing, cover and diameter are your inputs. The model counts one rectangular layer and requires each cut to fit one stock bar. Stock estimates batch each orientation separately and exclude laps, hooks, anchorage and shared offcut optimization. Review the units, period and assumptions before comparing scenarios. Displayed values are rounded, while the underlying calculation retains its available precision.

A worked example

A 10 × 10 ft grid with zero cover and 12-inch spacing has 11 bars in each direction, totaling 220 feet of cuts.

Reading your result

Use the main result together with its units and supporting figures. Display values are rounded; calculations keep their underlying precision. A change in inputs or assumptions can change the answer. Compare the step-by-step working with your intended use before relying on an estimate.

Frequently asked questions

What assumptions does this calculation use?

Spacing, cover and diameter are your inputs. The model counts one rectangular layer and requires each cut to fit one stock bar. Stock estimates batch each orientation separately and exclude laps, hooks, anchorage and shared offcut optimization.

Can I save or check a scenario?

The result includes the working and supporting values. Save and Restore keep inputs on this device; Copy, Download and Print export the result. Sharing a scenario explicitly includes the inputs in its link.

Sources & methodology

This calculator uses the mathematical identity and assumptions stated above. No current rates, prices, or external data are loaded. Conversion tools use international unit definitions.

Formula review: October 24, 2026. Read our methodology.