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What size strimmer line do I need

Updated: October 2026

You are standing in the shed with a cordless or mains grass trimmer. What size strimmer line do I need is answered by the number on the manual and the hole in the head, not by how thick the weeds look. For many UK electric and cordless machines that number is 1.6 mm. If the head is marked 1.6 mm, the [1.6 mm strimmer line comparison](/hub/lawn-and-garden-equipment/1-6mm-strimmer-line) is the shelf to use. If it is marked 2.0 mm or 2.4 mm, leave that page. Peter F. used amazon.co.uk listings from 19 October 2026. No lab test. A qualifying purchase can earn a commission at no extra cost to you.

You are standing in the shed with a cordless or mains grass trimmer. What size strimmer line do I need is answered by the number on the manual and the hole in the head, not by how thick the weeds look.

Our top picks

Oregon Oregon (Star, 15 m)

Best overall

Oregon Oregon (Star, 15 m)
7.2/10about £8.28
View offer
SOL SOL (1.6 mm, two-pack)

Rank 2

SOL SOL (1.6 mm, two-pack)
8.0/10about £5.99
View offer
FEPITO FEPITO (Round, 30 m)

Best value

FEPITO FEPITO (Round, 30 m)
7.8/10about £3.79
View offer
On this page
  1. 1.Read the manual and the eyelet before the reel
  2. 2.What 1.6 mm is for
  3. 3.Round line or star line
  4. 4.Metres on the packet

Read the manual and the eyelet before the reel

The diameter is fixed by the machine. Toolbuyerhub’s size guide says you do not pick a tougher line to stop snaps, because a thicker cord ovalises the eyelet and then breaks there. If the manual and the hole both say 1.6 mm, that is the buy. If the booklet is missing, use the mark on the spool cover. Yourspares groups 1.5–1.6 mm with domestic electric and cordless trimmers on edges and light weeds. That is retailer guidance, not a British Standard. Line which is too thick strains the motor, and line which is too thin breaks. 0.065 inch is about 1.65 mm, not a promise that every 1.65 mm title will pass a tight 1.6 mm hole. If the head is not 1.6 mm, the 1.6 mm or 2.4 mm page is the decision.

What 1.6 mm is for

1.6 mm line is for light edges, lawn fringes, and small weeds on a small electric or cordless trimmer. It is not a brushcutter cord, and it is not a substitute for a blade on brambles or woody stems. A neglected allotment of thick stalks will snap a 1.6 mm spool, and upsizing only helps when the manual allows the next size. ManoMano’s two-stroke chart does not describe an 18 V trimmer. A printed range such as 1.6–2.0 mm is not permission to jump to 2.4 mm.
Oregon Oregon (Star, 15 m)

Testsieger

Oregon Oregon (Star, 15 m)
7.2/10about £8.28
View offer

Round line or star line

Round nylon is the usual feed for a domestic bump head. The long reels in this set that name a profile are round. SOL’s two-pack states 1.6 mm and does not name a profile, so do not assume it is star line. Serrated line in the ManoMano guide starts up around 3 mm. Star line is the shaped option when the head will take it. Oregon’s 1.6 mm by 15 m donut is sold with five cutting edges for medium and long grass. If the manual only says round 1.6 mm, do not fit the star donut because the packet looks more serious. If the manual allows star line at 1.6 mm, the best 1.6 mm strimmer line page separates that donut from the long generic reels.

Metres on the packet

The head holds a few metres, not the whole reel. A reload guide uses about 3–5 m a side, or the moulded fill line, as a rule of thumb. The manual wins when the two disagree. A 15 m donut and a 100 m reel are different shopping habits for the same small head. On the 19 October 2026 amazon.co.uk capture, FEPITO’s 30 m round line was about £3.79 and ASOENTIWOX’s 100 m round line was about £6.98. Once the diameter is settled, the wind is on the how to load strimmer line page.

Common questions

What size strimmer line do I need?
You need the diameter printed for your trimmer, checked against the eyelet. For many UK domestic electric and cordless machines that is 1.6 mm, the light size Yourspares groups with edges and light weeds. Thicker line is for a machine that states it. A weed that looks tough does not change the hole in the head.
Is 1.6 mm the same as 0.065 inch?
0.065 inch is about 1.65 mm, so listings often treat it as the same thin class as 1.6 mm. It is not a guarantee that a 1.65 mm cord will enter a tight 1.6 mm spool hole. Zeqeey states both figures. Confirm against the manual before you order.
Is 1.65 mm close enough for a 1.6 mm head?
Sometimes, and only if the head is happy with that thin class. Oregon’s round listing is titled 1.65 mm by 15 m and the size field says 1.6 mm by 15 m. Treat that as mixed labelling, not as proof the two are identical. If the manual says 1.6 mm only, prefer a listing whose title and size field both say 1.6 mm, such as FEPITO’s 30 m round line.
Round or star for a small electric trimmer?
Round line is the usual choice, because most bump heads are built to feed it. Star line, such as Oregon’s five-edge 1.6 mm donut, is for a cleaner cut in longer grass when the manual allows that profile. A shaped line that the eyelet will not pass is worse than plain round line that feeds. Square and serrated line are a poor default at 1.6 mm.
How long a reel should I buy if the head only holds a few metres?
Buy the length you want in the cupboard. The head typically takes a few metres a side, often about 3–5 m or up to a fill line, and the manual wins if the two disagree. A 15 m donut suits a small lawn. A 100 m reel suits weekly edging if you keep it out of a hot, dry shed.

Related pages

Strimmer line keeps snapping

1.6 mm strimmer line

Best 1.6 mm strimmer line for your confirmed UK head

How to load strimmer line onto a domestic bump head

1.6 mm vs 2.4 mm strimmer line: when you can move up

Sources

Public UK sources named in the research digest. Amazon prices, stars and review counts are the eight listings captured on 19 October 2026.

  1. Yourspares — how to choose strimmer line (retrieved 19.10.2026)
  2. Yourspares — strimmer line sizes explained (retrieved 19.10.2026)
  3. Yourspares — strimmer line keeps breaking (retrieved 19.10.2026)
  4. ManoMano UK — trimmer line buying guide (retrieved 19.10.2026)
  5. STIHL UK — grass trimmer PPE (retrieved 19.10.2026)
  6. STIHL UK — replacing trimmer line (retrieved 19.10.2026)
  7. Husqvarna UK — how to reload trimmer line (retrieved 19.10.2026)
  8. HSE — INDG480 hand-arm vibration in horticulture (retrieved 19.10.2026)