Weight of round steel bar from its diameter and length, by the d squared over 162 rule
Runs in your browser. Nothing you type is sent anywhere. Updated on 25 Oct 2026.Steel Weight Calculator turns a bar diameter into kilograms. A 12 mm round bar weighs 0.888 kg per metre, so a 12 metre length is 10.65 kg and 50 of them come to 533 kg. The d squared over 162 shorthand and the exact figure from your own steel density are shown together.
Tap a standard diameter chip, or type the "Diameter" in mm.
Under "Measure the lot by", choose "Number of bars" and set "How many bars" and "Length of one bar", or choose "Total length".
Pick the metal chip, such as "Mild steel / TMT rebar", or type the "Density"; add a "Price per kg (optional)".
Read "Total weight", "Per metre" and the d² ÷ 162 check, and open "How it is worked out" for the steps.
Press "Share result" to copy a link with these inputs.
Every site in India uses the same shorthand for rebar: diameter squared, divided by 162, gives kilograms per metre. A 12 mm bar is 144 over 162, which is 0.888 kg a metre. A 16 mm bar is 1.58, a 20 mm bar is 2.47.
That 162 is not handed down from a standard. It is the area of a circle with steel's density folded into it and the result rounded. Written out, kilograms per metre is density times pi over four times the diameter in metres squared. Put 7850 kg per cubic metre into that and the divisor comes out at 162.2, so the familiar 162 is about a sixth of a per cent generous. Over a tonne of steel that is under two kilograms, which is why nobody minds.
This page shows both. The exact figure comes from whatever density you set, and the shorthand sits beside it so you can see how far apart they are. Density is a box because mild steel, stainless and aluminium are not the same metal, and because a supplier's test certificate is a better source than a round number.
Measure the lot either way. Count bars of a known length, with 12 metres as the standard mill length in India and 6 metres common as cut stock, or type a running length you have already added up from a bar bending schedule.
Three figures come back besides the total: kilograms per metre, kilograms per bar, and how many full bars make a tonne. That last one is the number to check a delivery against, since rebar is sold by weight and delivered by count.
For a schedule with several diameters, run the page once per diameter and add the results. Nothing typed here leaves your browser.
Diameter in millimetres, squared, divided by 162 gives the weight of a round steel bar in kilograms per metre. A 12 mm bar is 144 over 162, or 0.888 kg a metre. The formula is the circle area multiplied by a steel density of 7850 kg per cubic metre, rounded.
One million divided by pi over four times 7850 comes to 162.2. Site practice rounds that to 162 because the difference is 0.17 per cent, under two kilograms in a tonne. Both figures appear on this page so the gap is visible rather than hidden inside the answer.
0.888 kg per metre, so a standard 12 metre bar weighs about 10.65 kg and a tonne holds roughly 94 of them. A 6 metre cut length is half that, 5.33 kg. Change the density box if your supplier's test certificate quotes something other than 7850 kg per cubic metre.
Yes, for any round bar, by changing the density. Aluminium at 2700 kg per cubic metre gives a divisor near 472 instead of 162, and stainless at 7900 is a shade heavier than mild steel. The 162 shorthand stays on screen and is visibly wrong for anything but steel.
About 94 bars of 12 metres, since each weighs 10.65 kg. For 8 mm bars of the same length the count rises to roughly 211, and for 16 mm it falls to about 53. The bars-per-tonne figure on this page is the one to check a delivery note against.
Not in one pass. The page takes one diameter at a time, which keeps the arithmetic checkable line by line. Run it once for each diameter in your schedule and add the totals; the running-length option accepts a figure you have already summed from the drawings.
Formula only: no rates or limits are read from an official source.
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