Roundup weed killer buying guide

Updated: October 2026

You have weeds in a paving joint, or a bramble against the fence, and amazon.co.uk has put Roundup on a trigger, a pump refill and a concentrate.

You have weeds in a paving joint, or a bramble against the fence, and amazon.co.uk has put Roundup on a trigger, a pump refill and a concentrate. This roundup weed killer buying guide is the order of decisions before you pay: which chemistry the bottle is, which format matches the kit you own, and whether the coverage figure matches the ground in front of you. Stars, prices and the top pick stay on the Roundup weed killer comparison. The chemistry split is on Roundup glyphosate free or glyphosate. We set this on 16 October 2026 from these amazon.co.uk listings. We did not spray a plot. A qualifying purchase can earn a commission at no extra cost to you.

Our top picks

Badge	Product	Format	Active	Coverage claim	Note	Price	Offer
Best overall	Roundup Roundup Total Optima	Ready to use	Pelargonic acid	Not stated	7.9	about £16.98	View offer
	Roundup Roundup Total Fast Action	Ready to use	Glyphosate	Not stated	8.6	about £12.98	View offer
Best value	Roundup Roundup Path	Ready to use	Cell: green	Up to 30 m²	8.2	about £8.84	View offer

Best overall

Roundup Roundup Total Optima

7.9/10about £16.98

View offer

Rank 2

Roundup Roundup Total Fast Action

8.6/10about £12.98

View offer

Best value

Roundup Roundup Path

8.2/10about £8.84

View offer

On this page

1.Two Roundups, not one
2.Read the active line, then distrust it
3.Trigger, pump, refill or concentrate
4.Coverage is not the size of your drive
5.What the bottle must say before you pay

Two Roundups, not one

Roundup on the label is a brand, not a mode of action. Glyphosate is named on the Fast Action twin (B0HGBK3T8H, £12.98 for 2×1 litre), the 5 litre refill (B01CNEM3EG, £25.99), XL Tough (B005ZALTE6, £23.89, listed at 90 m²), Ultra (B079TGDH5T, £29.99) and the Tough concentrate (B01BWVLHPM, £52.66, up to 100 litres or 3,000 m²). Love the Garden’s Fast Action page calls that ready-to-use line systemic, at 7.2 g/L glyphosate, with a result in one to two days. Its grid ticks root kill for Fast Action, Path and Tough, and not for Total Optima. Pelargonic acid is the other mode in this basket. The two Total Optima listings, B0G4XVZBV6 at £16.98 and B0CT3X321Q at £29.98, carry a glyphosate-free bullet. The 5 litre pump claims 165 m², a three-hour rain window and replanting in three days. Optima+ is a third name, not a synonym. On the brand grid it is the glyphosate concentrate, with a root-kill tick. If you buy “Optima” because you wanted no glyphosate, you can leave with the opposite bottle.

Read the active line, then distrust it

Amazon’s active-ingredient cell is not a reliable substitute for the bottle. The path listing B01MSANUPH (£8.84, up to 30 m²) has an active cell that says “green”. Three other listings, B0HGBSQCZG, the stump bottle B01BY4FFPK and the Optima+ listing B01BY4FOB0, have an active cell that says ferrous sulphate. The brand’s own ingredient list does not describe those lines as ferrous sulphate weedkillers. B01BY4FOB0 is messier still: the URL and the specification do not agree, and the specification points at ASIN B01BY4FFEQ. Treat “green” as a missing fact. Ferrous sulphate is what many lawn feeds use on moss, so the cell invites the wrong job. Open the label photograph before you pay. The Weed Guy separates Fast Action, Tough, Optima+, Ultra and stump from Total Optima and Path Optima. That page’s MAPP numbers are not in our raw files, so they are not repeated as HSE-checked. Path Optima on that table is not our path listing, whose cell says “green”.

Testsieger

Roundup Roundup Total Optima

7.9/10about £16.98

View offer

Trigger, pump, refill or concentrate

Match the pack to the sprayer you already have. If you can see a handful of weeds and you do not own a lance, a ready-to-use trigger is the format that leaves the shed. The Fast Action twin, the path trigger and the Total Optima twin each fail if the job is a long drive or a stump. A refill is not a sprayer. B01CNEM3EG at £25.99 needs a Pump 'N Go that still works, and a review described a cap that would not unscrew. B0CT3X321Q at £29.98 includes a pump, but the chemistry is pelargonic acid and a review describes a broken handle. The 3 litre XL Tough had a review with no gun. A large pack with no working lance is stored weedkiller. The concentrates are for a tank you will mix. Ultra is 500 ml at £29.99. The Tough concentrate at £52.66 is the high shelf price in the set. It is not a stronger ready-to-use spray. If you have no sprayer, that £52.66 does not buy you one. Hard surfaces, and why a 30 m² trigger is the wrong size for a long drive, are on Roundup weed killer for patios and driveways.

Coverage is not the size of your drive

The square metres on these listings are label arithmetic, not a survey of your path. Claims in this set include up to 30 m² on the path bottle, 90 m² on the 3 litre Tough, 165 m² on the Total Optima pump, and further claims of 810 m² and 3,000 m². The 3,000 m² figure sits on B01BWVLHPM beside “up to 100 litres”. The Weed Guy reads “up to 100 litres” as the weak rate across the whole bottle. That is that site’s reading, not a measurement we made. A 1 litre path claim of 30 m² is a short run of joints. A drive about 3 metres wide and 15 metres long is already about 45 m². The 90 m² Tough claim only helps if the gun is in the box. The 165 m² Optima claim is contact spray, not a dead root. Which bottle suits which job is on the best Roundup weed killer in this set.

What the bottle must say before you pay

Before checkout, the label has to clear checks the brand name does not. None of these listings is a lawn weedkiller. Love the Garden’s Fast Action instructions say leave seven days before digging, and the HSE page states glyphosate approval until 15 December 2026. That date is not a ban, and it does not run on with no further decision. Total Optima is still non-selective, so a glyphosate-free bullet does not put it on grass. Confirm amateur use on the bottle, not on a professional Roundup ProActive page, which is outside this set. Confirm the active ingredient in words you can read, because “green” and “ferrous sulphate” have already failed that test. A stump is a different product from a path trigger, and it does not rot the wood.

Common questions

Should you buy Roundup ready to use or concentrate?

Buy ready to use when you can see the weeds and you have no sprayer to fill. Buy concentrate when you will mix a tank and you accept that “up to 100 litres” is, on The Weed Guy’s reading, the weak rate across the bottle. Compared with a 1 litre trigger, the £52.66 Tough concentrate is spare money if the lance stays in the shed.

Does Optima mean the bottle is glyphosate-free?

Only Total Optima, in this set the listings B0G4XVZBV6 and B0CT3X321Q, carries the glyphosate-free bullet, and the active is pelargonic acid. Optima+ is the glyphosate concentrate on the Love the Garden range grid, with a root-kill tick. The plus sign is the difference. A title that stops at Optima is not enough to choose.

Why does Amazon say ferrous sulphate?

On B0HGBSQCZG, B01BY4FFPK and B01BY4FOB0 the active-ingredient cell says ferrous sulphate, and on the path bottle it says “green”. The brand ingredient list does not describe those lines that way. Ferrous sulphate is what many lawn feeds use on moss, so the cell suggests the wrong job. Read the label photograph. If it does not name glyphosate or pelargonic acid, do not treat the cell as the formula.

Is a 5 litre refill a complete sprayer?

No. B01CNEM3EG at £25.99 is a refill for a Pump 'N Go you already have. A review described a cap that would not unscrew. The Total Optima 5 litre, B0CT3X321Q, includes a pump, but a review describes a broken handle, and the chemistry is pelargonic acid rather than glyphosate. A 5 litre pack with no working lance does not treat a path today.

What do “up to 100 litres” and “3,000 m²” mean?

On B01BWVLHPM those figures are the listing’s coverage claim for the concentrate, not a map of a garden. The Weed Guy treats “up to 100 litres” as the weak dilution across the whole bottle. We did not measure this ASIN, and a large square-metre number does not make the spray suitable for a lawn. If your weedy ground is a few joints, the claim is mostly stored mix.

Can any of these go on a lawn?

No listing in this set is for lawns. Glyphosate and pelargonic acid are both non-selective, so grass in the spray is a plant you have hit. Do not walk wet product onto the lawn. Glyphosate remains approved for authorised products until 15 December 2026, which is an HSE date, not a reason to spray turf. Brambles and stumps are a different job from slab gaps: the stump listing is sold to stop regrowth, and reviewers say it does not rot the wood.

How to use Roundup weed killer