---
title: "Rebar Calculator"
description: "Rebar weight, length and bars-per-tonne takeoff for any size list — free."
image: "https://nestingcalc.com/og-default.png"
url: "https://nestingcalc.com/rebar-calculator/"
locale: "en"
---

# Rebar Calculator

Rebar weight, length and bars-per-tonne takeoff for any size list — free.

Enter each rebar size with length and quantity. The calculator computes weight per bar (π/4 × d² × 7850 kg/m³), total tonnes for your order and how many bars make one tonne — for both metric and US imperial sizes.

Interactive calculator (open in browser): [https://nestingcalc.com/rebar-calculator/](https://nestingcalc.com/rebar-calculator/)

## Rebar weight chart

| Diameter (mm) | kg/m | lb/ft | m per tonne |
| --- | --- | --- | --- |
| Ø6 | 0.222 | 0.149 | 4505 |
| Ø8 | 0.395 | 0.265 | 2534 |
| Ø10 | 0.617 | 0.414 | 1622 |
| Ø12 | 0.888 | 0.597 | 1126 |
| Ø14 | 1.208 | 0.812 | 828 |
| Ø16 | 1.578 | 1.061 | 634 |
| Ø20 | 2.466 | 1.657 | 405 |
| Ø25 | 3.853 | 2.589 | 260 |
| Ø28 | 4.834 | 3.248 | 207 |
| Ø32 | 6.313 | 4.242 | 158 |
| Ø40 | 9.865 | 6.629 | 101 |

## FAQ

How is rebar weight calculated?

Weight per metre follows the section formula π/4 × d² × 7850 kg/m³, which is the exact form of the classic d²/162 rule of thumb. Results match steel supplier tables within rounding.

Does it include laps and wastage?

No — enter the cut lengths you need. For laps, add the lap length to each bar; for wastage, add a percentage to the quantity (e.g. 3 extra bars per 100).

Can I use US bar sizes?

Yes, the size dropdown includes #3–#11 US bars alongside metric 6–40 mm. US sizes are converted to their metric diameters internally.

How many 12 mm rebar bars are in a tonne?

A 12 mm bar weighs 0.888 kg/m, so one tonne is 1,126 m — about 93 twelve-meter bars. The chart above lists kg/m and bars per tonne for every metric and US size.

## Related calculators

-   [Metal Weight Calculator — Rod, Tube & Bar](https://nestingcalc.com/metal-weight-calculator/)

    Weight of steel, stainless, aluminum, copper & brass rods, tubes, bars and beams in kg/m. Density table included. Free.

-   [Sheet Metal Gauge Calculator](https://nestingcalc.com/sheet-metal-gauge/)

    Convert gauge to mm/inch and get sheet weight — steel, stainless, aluminum, galvanized. Free.

-   [Linear Cutting Calculator](https://nestingcalc.com/linear-cutting-calculator/)

    Optimize cuts for bars, pipes and profiles — minimize waste, free.

## Related guides

-   [Rebar Weight Chart and Bar Bending Schedule Basics](https://nestingcalc.com/guides/rebar-weight-chart/)

    The d²/162 rule turns rebar drawings into kilograms in seconds. Here is how it works, plus how stirrups and bend deductions affect the tonnage.

-   [Metal Weight Formula: Steel, Aluminum, Stainless by Profile](https://nestingcalc.com/guides/metal-weight-formula/)

    Weight drives shipping cost, crane planning and material budgets. One formula covers every metal profile — you only need the density.

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