Rebar Calculator: Reinforcement Steel Weight and Bar Count
Calculate total weight, bar count, and lap length recommendations for reinforcement steel.
Last updated: January 2026
| # | Diameter | Length (m) | Qty | |
|---|---|---|---|---|
| 1 |
Total Weight
53.28 kg
Weight in Tons
0.053 t
Standard Bars (12 m)
5 bars
| Dia. | kg/m | Total Length | Weight | Bars (12 m) |
|---|---|---|---|---|
| 12 mm | 0.888 | 60 m | 53.28 kg | 5 |
IMPORTANT DISCLAIMER
This calculator provides PRELIMINARY ESTIMATES ONLY and is intended for planning and budgeting purposes. Results should NOT be used for final structural design or construction without verification by a licensed Professional Engineer (PE) or Chartered Engineer (CEng).
By using this tool, you acknowledge that:
1. All calculations are indicative and may not account for site-specific conditions, load combinations, or local code requirements.
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About This Calculator
The Rebar Weight Calculator helps quantity surveyors and structural engineers estimate reinforcement steel tonnage for construction projects across the UAE and Gulf. Calculate weight per bar, total tonnage, bar count, and lap length requirements. Essential for procurement, tender submissions, and verifying steel deliveries.
Formula
Unit weight w (kg/m) = π/4 × d² × 7,850 kg/m³, with d in metres. The calculator uses the standard table values: 8 mm = 0.395, 10 mm = 0.617, 12 mm = 0.888, 16 mm = 1.578, 20 mm = 2.466, 25 mm = 3.853, 32 mm = 6.313, 40 mm = 9.864 kg/m.
Total length of a line item = bar length × quantity
Weight of a line item = total length × w
12 m stock bars for a line item = ⌈total length ÷ 12⌉ (rounded up per line item)
Lap length (mm) = lap multiplier × bar diameter d (35d, 40d, 45d or 50d)
Weight in tonnes = total weight in kg ÷ 1,000
Worked example
Inputs
- Item 1: 16 mm bars, 6 m long, quantity 100
- Item 2: 10 mm bars, 1.2 m long, quantity 250
- Lap multiplier: 40d
Steps
- Item 1: 6 m × 100 = 600 m; 600 m × 1.578 kg/m = 946.8 kg; ⌈600 ÷ 12⌉ = 50 bars
- Item 2: 1.2 m × 250 = 300 m; 300 m × 0.617 kg/m = 185.1 kg; ⌈300 ÷ 12⌉ = 25 bars
- Total weight = 946.8 + 185.1 = 1,131.9 kg = 1.132 tonnes
- Total stock bars = 50 + 25 = 75
- Lap lengths at 40d: 16 mm = 640 mm; 10 mm = 400 mm
Result: 1,131.9 kg (1.132 tonnes) of reinforcement, 75 bars of 12 m
Assumptions and limits
- Weights use the standard unit weights per metre for plain round-equivalent sizes; actual mill weights vary within the permitted tolerance of the product standard.
- Stock bars are assumed to be 12 m long. Check the lengths your supplier actually delivers.
- Bar counts are rounded up per line item, so offcuts are not reused between items.
- Lap lengths are shown as a recommendation only and are not added to the weight. Hooks, bends, spacers and cutting waste are not included.
- Required lap lengths depend on bar grade, concrete strength, bar position and the governing code: check the governing code and project specification.
When to Use This Calculator
- Preparing steel procurement orders for structural works
- Estimating reinforcement quantities for tender submissions
- Verifying steel delivery weights against bar schedules
- Calculating bar cutting lengths with lap requirements
- Pricing reinforcement packages for subcontract quotations
How to Use This Calculator
Select Bar Diameter
Choose the rebar size: 8mm, 10mm, 12mm, 16mm, 20mm, 25mm, 32mm, or 40mm.
Enter Bar Length
Input the cutting length per bar in meters (standard bar length is 12m).
Enter Number of Bars
Specify the total bar count from your bar schedule or estimation.
View Weight Results
Get weight per bar, total weight in kg and tonnes, and lap length recommendations.
Frequently Asked Questions
What is the weight of 12mm rebar per meter?
12mm rebar weighs 0.888 kg per meter. For a standard 12m bar: 0.888 × 12 = 10.66 kg per bar. This is calculated using the formula: weight (kg/m) = diameter² × 0.00617.
How do I calculate lap length for rebar?
Lap length is a multiple of the bar diameter that depends on the code, steel grade and concrete strength; this calculator offers 35d, 40d, 45d and 50d. For 16mm bar in tension: 40 × 16 = 640mm (65cm). Gulf standards may require longer laps; consult your structural engineer.
How many tonnes of rebar per cubic meter of concrete?
Reinforcement quantity per cubic metre varies widely with the element, the span, the loads and the design code, so there is no single ratio to rely on. Take quantities from the bar bending schedule or the structural drawings. The rebar calculator works from the bar sizes, lengths and spacings you enter.
Last Updated: January 2026
Standards Reference: Weight calculations per BS 4449 and ASTM A615 standards
