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Best reinforcing steel bar

Updated: 23 October 2026

You are comparing short reinforcing steel on amazon.co.uk, and a star sort will not tell you the diameter. Three Just The Job listings share 4.5 from 357 ratings and the same 50 texts, so that headline is one parent sample on three baskets. The best reinforcing steel bar here is the pack whose diameter, length, and piece count match the job, with the clashes left in view. The table is the [reinforcing steel comparison](/hub/diy-supplies/reinforcing-steel). This page says who each pack is for, and who should leave it. Products Compared used those listings, in GBP, and did not award a winner. A qualifying purchase can earn a commission at no extra cost to you.

You are comparing short reinforcing steel on amazon.co.uk, and a star sort will not tell you the diameter.

Our top picks

Just The Job Supplies Just The Job 8 mm bar, 10 × 1 m

Best overall

Just The Job Supplies Just The Job 8 mm bar, 10 × 1 m
9.2/10about £25.20
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Just The Job Supplies Just The Job 10 mm bar, 2 × 1 m

Alternative

Just The Job Supplies Just The Job 10 mm bar, 2 × 1 m
9.0/10about £12.26
View offer
Just The Job Supplies Just The Job 12 mm bar, 5 × 450 mm

Alternative

Just The Job Supplies Just The Job 12 mm bar, 5 × 450 mm
9.0/10about £15.32
View offer
On this page
  1. 1.The shared 357 is one parent, three baskets
  2. 2.The seven packs by the job they fit
  3. 3.Pence per metre against a merchant bar
  4. 4.What the filed reviews actually cover

The shared 357 is one parent, three baskets

B07NWMKJMY, B07NWR8VYY, and B07NWQGZB4 all show 4.5 from 357, and the 50 texts are the same sample. They mention other lengths, rust, and jagged or bent ends. A complaint in that file may belong to another diameter, so 4.5 cannot separate a 10 mm metre from a 12 mm stub. The other headlines are smaller files. B09PRTY1B2 is 4.5 from 80. B0CT93P3DB is 4.6 from 33. B0CTCQW3QG is 4.8 from 37. B0GKPX9WMY is 4.9 from 12, and its grade field says Commercial. What B500 B/C fails to pin down is on the reinforcing steel buying guide.

The seven packs by the job they fit

Take B07NWMKJMY at £12.26 for two metres of 10 mm if you will gauge it: the thickness field says 8 mm and the weight is 100 g. The bullets say B500 B/C, two classes, with no CARES line. Take B07NWR8VYY at £20.45 for five 1 m bars of 10 mm. Its diameter field says 12 mm and its thickness field says 8 mm, on the same 4.5 from 357. B&Q lists five 1 m by 10 mm bars at £17.70. B07NWQGZB4 at £15.32 is the only 12 mm bar, five lengths at 450 mm, with number of items at 10 against a title of five. A shared review calls 450 mm right for log steps. That is not the 450 mm foundation depth in Approved Document A. Take B0CT93P3DB at £25.20 for ten metres of 8 mm when both fields say 8 mm and there is no BS 4449 line. Take B0CTCQW3QG at £33.48 for ten metres of 10 mm and gauge it: part number RSB081000-10 looks like an 8 mm code. Skip the Commercial pack at £14.55 when a grade is specified, and skip ten 6 mm bars at £21.73 when the under-8 mm note matters.
Just The Job Supplies Just The Job 8 mm bar, 10 × 1 m

Testsieger

Just The Job Supplies Just The Job 8 mm bar, 10 × 1 m
9.2/10about £25.20
View offer

Pence per metre against a merchant bar

The cheapest pack is not the cheapest metre. Two 1 m bars of 10 mm are about £6.13 a metre, five of 8 mm about £2.91, and five 450 mm bars of 12 mm about £6.81. Five 1 m bars of 10 mm are about £4.09. The ten-bar packs are about £2.17 a metre for 6 mm, £2.52 for 8 mm, and £3.35 for 10 mm. The Metal Store lists 3 m of 8 mm, 10 mm, and 12 mm at £6.30, £9.00, and £10.80 including VAT. Next Day Steel lists 3 m of 10 mm at £5.56 including VAT. A trade length of 10 mm can sit near £1.30 to £2 a metre including VAT, against roughly £3 to £6 for these 1 m cuts. Buy the short pack when postage is the point. Cover and cutting are on how to fix reinforcing steel.

What the filed reviews actually cover

The shared texts are the only file here that repeatedly names rust on arrival and bent or jagged ends. Tight rust can be acceptable in concrete. Flaky rust, oil, mud, and lost section are not. Silence in a shorter file is not a test. Leave the basket if you need one named grade and a certificate. None of these listings is CARES-certified in the capture.

Common questions

Which pack is the 12 mm short bar, and which is ten 10 mm bars?
The only 12 mm listing is B07NWQGZB4, five bars at 450 mm for £15.32. Ten 10 mm bars at 1 m are B0CTCQW3QG at £33.48. They are not interchangeable. The 12 mm pack shares the 357-review file. The ten-bar pack has eight of its own texts and no BS 4449 line in this capture.
Why does 4.9 from 12 not choose the pack?
B0GKPX9WMY is 4.9 from 12 ratings, and the file holds three UK texts. The grade field says Commercial. Number of items is 20 against a selected pack of five. A high star line on twelve ratings does not name a ductility class and does not check the count fields. Skip it when the specification names a grade.
What does the 6 mm ten-pack cost, and why is 6 mm a different question from 8 mm?
B09PRTY1B2 is ten 1 m bars of 6 mm at £21.73, about £2.17 a metre. The Concrete Centre says bar below 8 mm does not meet Eurocode 2 ductility. An 8 mm pack can still lack a BS 4449 line, as B0CT93P3DB does, but it is not caught by that under-8 mm note. The 6 mm pack is also not a sheet of A142.
Do the UK texts on the 8 mm and 10 mm ten-packs mention rust or a short count?
In the filed texts, no. The 8 mm pack has 13 UK texts behind 4.6 from 33, and the 10 mm pack has eight behind 4.8 from 37. None of those texts names a short count or a wrong diameter. The 8 mm texts do not name flaking rust. The 10 mm texts do not name rust. That is a partial sample, not a certificate, and nobody in either file mentions a BS grade.
Is £12.26 for two 1 m bars of 10 mm cheaper per metre than £25.20 for ten 1 m bars of 8 mm?
No. Two bars at £12.26 are about £6.13 a metre. Ten 8 mm bars at £25.20 are about £2.52 a metre. The smaller basket total is the dearer metre, and the diameters are not the same. Compare a metre only after the drawing has fixed the size.

Related pages

Reinforcing steel or mesh

Reinforcing steel

Reinforcing steel buying guide for diameter and grade

Reinforcing steel for foundations and plain strips

How to fix reinforcing steel with chairs and cover

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Updated 23 October 2026.

  1. CARES specification guide (retrieved 23 October 2026)
  2. CARES bar mark (retrieved 23 October 2026)
  3. Concrete Centre: European standards for reinforcement (retrieved 23 October 2026)
  4. LABC: reinforcement in foundations (retrieved 23 October 2026)
  5. Concrete Society: cover to concrete cast against the ground (retrieved 23 October 2026)
  6. Concrete Society: reinforcement contamination and rust (retrieved 23 October 2026)
  7. Approved Document A (retrieved 23 October 2026)
  8. Next Day Steel: 10 mm rebar (retrieved 23 October 2026)
  9. The Metal Store: reinforcing bar (retrieved 23 October 2026)
  10. HSENI via NISG: alternatives to grinding (retrieved 23 October 2026)