Concrete calculator

Steel weight calculator

Rebar mass per metre, per bar and for a stated bar count from nominal diameter and steel density.

By Feroz Sheikh · Formula GCC-STEEL-001 v1.0.0 · Tested formula

FormulaGCC-STEEL-001v1.0.0

Project inputs

Enter your measurements. Switching units converts the same project, including coverage and unit rates. Package yields keep the unit printed beside each field.

Steel weight: measurement diagram. Use the specified nominal bar diameter, bar length, count and steel density. This weighs an entered schedule; it does not design reinforcement. — Use the specified nominal bar diameter, bar length, count and steel density. This weighs an entered schedule; it does not design reinforcement. View image

Bar diametermmNominal metric bar diameter, not the raised rib measurementLength per barmUse the bar length on the delivery scheduleBar countcountNumber of bars in this diameter and lengthSteel densitykg / m³Illustrative theoretical density; replace if specified by the supplierCut and lap allowance%Extra length allowance, not a bar-cutting optimization

Refine measurements and rates at any time. Your current values are included in the material-list PDF.

Calculated result

106.538kg

Total steel weight

FormulaGCC-STEEL-001

kg/m = π × (diameter mm / 1000)² / 4 × density; kg = kg/m × bar length × count × (1 + waste/100)

0.8878 kg/m

Weight per metre

10.654 kg

Weight per bar

120 m

Measured bar length

Planning estimate, not engineering advice. Confirm site measurements and product specifications. Calculation limits.

Find theoretical reinforcing steel weight from a metric diameter, bar length and count. The result uses circular area times the density you enter; manufacturing mass tolerances remain with the supplier.

Read diameter and length from the approved bar schedule.
Keep different diameters on separate lines.
Use the allowance only for additional length that is not already counted.

Add your project costs

Enter supplier prices and any labour, equipment or delivery costs. Pick a currency — badges, inputs, and totals follow.

Enter your supplier’s ready-mix concrete rate in the selected unit. Add delivery, pumping, short-load fees and placing labour as separate project costs. For GCC projects, select QAR, AED, SAR, KWD, OMR or BHD and enter local supplier rates.

View estimate Quote / invoice Add another item

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How this calculator works

A transparent steel weight takeoff.

Feroz SheikhWritten by Feroz Sheikh · founderFormula GCC-STEEL-001 v1.0.0 automated checks Oct 3, 2026.

GCC-STEEL-001 weighs each diameter-and-length group from circular nominal area and the entered steel density. Keep a separate line for every bar schedule size so that a single averaged diameter cannot distort the order mass.

Worked example. For a 12 mm bar at 7,850 kg/m³, mass is 0.888 kg/m. One 12 m bar is about 10.65 kg and ten bars are about 106.54 kg before any extra allowance.

See the example inputs and calculated result

This separate example uses the calculator's starting values in imperial units. It stays unchanged when you edit the tool above. Example rates, yields and dimensions are assumptions, not recommendations for your project.

Steel weight: example inputs
Input	Example value
Bar diameter	12 mm
Length per bar	12 m
Bar count	10 count
Steel density	7,850 kg / m³
Cut and lap allowance	0 %

Example result: Total steel weight — 106.538 kg.

kg/m = π × (diameter mm / 1000)² / 4 × density; kg = kg/m × bar length × count × (1 + waste/100)

Use the labelled units above when reproducing this example. To work in metric, switch the calculator to Metric; applicable measurements are converted, while product-specific units remain labelled.

1. Read diameter and length from the approved bar schedule.
2. Keep different diameters on separate lines.
3. Use the allowance only for additional length that is not already counted.

Field notes that change the number

Read nominal diameter from the bar certificate or schedule, not across the raised ribs.
A 12 m stock length is a purchasable length, not automatically the developed length of a bent bar.
Compare the theoretical total with the supplier weight tolerance; bends, hooks and laps belong in the schedule.

Common mistakes

Using a US bar number as a metric diameter.
Entering millimetres in the metre bar-length field.
Adding lap allowance when the bar schedule already includes it.

Need the broader workflow? Read the concrete planning guide.

Questions

Questions about steel weight

Why is D²/162 only approximate?

The density-based formula is π × D² × 7,850 / 4,000,000 kg/m, close to D²/162.2. Actual delivered weight is subject to the product standard and tolerances.

Does this calculate reinforcement needed?

No. It weighs a specified bar schedule; spacing, bar grade, anchorage and structural design remain with the engineer.

What is the formula ID?

This steel weight calculator publishes formula GCC-STEEL-001, version 1.0.0. The ID stays on the result and on the estimate line.