Rebar Weight Calculator

Reinforcing steel - or rebar - is sold by weight, shipped by weight, and priced by weight. Whether you are pouring a residential footing, ordering a tractor-trailer load for a commercial slab, or running a bar list off a structural drawing, the question always comes back to: how many pounds (or kilograms) of steel do I need? Our Rebar Weight Calculator answers that exactly, using the published nominal weights from ASTM A615 for imperial bars and BS 4449 / EN 10080 for metric bars. You can mix multiple sizes in a single takeoff, apply a waste factor, see how many stock bars to buy, and even estimate the cost and the number of truckloads.

Accurate rebar weight matters at every stage of a project. Estimators need it to price bids and forecast material spend. Detailers need it to convert shop drawings into bar lists. Field crews need it to verify deliveries and reject shortages. Project managers need it to plan crane picks and rigging. And contractors need it to avoid the very common - and expensive - mistake of ordering 30 percent more or less steel than the job actually requires. A consistent, formula-driven calculation that everyone on the team can reproduce eliminates that ambiguity.

Rebar weight is straightforward in principle: nominal weight per linear unit times total linear length times quantity. But the details add up. Sizes change between metric and imperial standards. Stock bars come in 20-foot, 40-foot, 60-foot imperial lengths or 6m and 12m metric lengths. Lap splices add measurable length to each run. Hooks at bar ends add their own developed length. Waste factors vary from 3 percent on simple slabs to 10 percent on heavily detailed walls and columns. The calculator handles all of these inputs so you do not have to keep a spreadsheet or cross-reference a paper chart every time you price a job.

The Rebar Weight Formula

The calculator uses the industry-standard nominal weight formula for every row:

For every row in your takeoff, the calculator looks up the nominal unit weight, multiplies by your length and quantity, then aggregates totals across the whole table. It also converts between imperial and metric on the fly using the constant 1 lb/ft = 1.488 kg/m, so a 20-foot #5 bar at 1.043 lbs/ft (20.86 lb) is also reported as 9.46 kg if you switch units.

Standard Rebar Sizes and Weights

Below is a reference for the bars supported in this calculator. Imperial weights come from ASTM A615 / A706 and metric weights from BS 4449 / EN 10080. These are nominal values - actual mill bars are within rolling tolerance of these numbers.

Common Use Cases

• Slab on grade takeoff: Use our Rebar Material Calculator to derive the total feet of bar needed at a given spacing, then drop the result into this weight calculator to convert linear feet into pounds, tons, and stock bars.
• Welded wire alternative comparison: When evaluating bars versus mesh, run the bar weight here and compare against our Concrete Mesh Calculator. You will often find that welded wire is cheaper for thin slabs and rebar wins for thicker slabs and footings.
• Concrete order sizing: Pair this with our Concrete Calculator to verify the rebar-to-concrete ratio is reasonable for your application (typically 100-250 lbs per cubic yard for slabs, 300-600 for columns and beams).
• Footing reinforcement: Use our Concrete Footing Calculator for footing geometry, then build a takeoff here with #4 horizontals and #3 stirrups using the included Footing Kit preset.

How to Use This Calculator

1. 1. Choose your unit system: Toggle to imperial for ASTM #3-#18 bars or metric for BS 6mm-40mm bars.
2. 2. Add a row per bar mark: For each unique combination of size and length on your bar list, add a row and set the quantity.
3. 3. Set advanced options: Adjust waste factor (default 5%), stock bar length, and enable cost mode if you have a supplier rate.
4. 4. Click Calculate: The calculator shows per-row weight, per-size breakdown, total tonnage, stock bars needed, truckloads, and material cost.
5. 5. Export or share: Save a text report for your records, attach it to a purchase order, or share the link with your team and supplier.

Pro Tips From the Field

• • Sort your bar list by length before ordering. Longer common lengths waste less when cut to size from stock bars. Group all 14-foot bars together, all 18-foot bars together, and so on.
• • Lap orientation matters: Splice in low-stress regions when possible. Lap splices in flexural members are typically placed at points of inflection or at the bottom of beams in negative moment regions, away from the worst stress.
• • Hooks add weight you cannot ignore: Standard ACI 318 90-degree and 180-degree hooks add 6-12 bar diameters of developed length. For a column tie kit with 40 hooks, that adds real pounds to the order. Always include hook length in your row entries.
• • Buy 20-foot bars for residential, 40-foot or 60-foot for commercial: Longer stock reduces splices and waste, but needs heavier handling equipment. Match stock length to your crane and rigging capacity.
• • Add 5% waste even on simple jobs: A small buffer covers miscounts on the bar list, damaged bars in shipping, and small site changes. It is far cheaper than a rush delivery for a dozen missing bars.
• • Verify the shipping weight on the BOL: When the truck arrives, the bill of lading should match (within 1-2%) the weight you calculated. Differences greater than 5% indicate a shipping error worth investigating before the truck leaves the site.

Imperial vs Metric Conversion

If you work on international projects or compare quotes from different markets, memorize one number: 1 lb/ft = 1.488 kg/m. That means a 20-foot #5 bar (20.86 lb) weighs 9.46 kg, and a 12m 16mm bar (18.94 kg) weighs 41.8 lb. The calculator does this conversion automatically, but doing it in your head is a useful skill on a job site or in a supplier conversation.

Cost Estimating With This Calculator

Rebar pricing fluctuates with steel mill rates. As of recent years, typical contractor pricing in North America has been in the range of $0.50 to $1.00 per pound for standard ASTM A615 Grade 60 bars, with bulk orders trending lower per pound. Epoxy-coated and stainless bars run 2-5x the cost of standard black rebar. Use the cost option in our calculator to convert your supplier's quoted rate (whether per pound, per US ton, per kilogram, or per linear meter) into a total material cost for the job. Add fabrication, delivery, and tax separately - those are typically quoted as line items on the supplier invoice.

Shipping and Logistics

A standard rebar flatbed truck carries about 20-25 US tons (18-23 metric tonnes) of bundled rebar within US highway weight limits. Long bars (40 feet or 60 feet) may need a stretch trailer and reduce effective per-truck weight. The calculator estimates truckloads using a 22-ton average. Always confirm with your supplier before assuming a single delivery covers your order - splitting an order across two trucks adds delivery fees but may be unavoidable for very large jobs.