115mm vs 125mm angle grinder
Updated: October 2026
You are in a UK garage with box section, a tile that needs a clean edge, or a bracket tucked into a corner, and the amazon.co.uk titles disagree about ten millimetres. This 115mm vs 125mm angle grinder page is only that choice, using the twelve listings in our [angle grinder comparison](/hub/tools/angle-grinder), captured on 20 October 2026. The larger disc buys a little more depth. It does not buy a different kind of machine, and it does not belong on the smaller guard. Prices and weights come from those listings beside Screwfix’s published depth figures. Nothing here is a lab cut. A qualifying purchase can earn a commission at no extra cost to you.
You are in a UK garage with box section, a tile that needs a clean edge, or a bracket tucked into a corner, and the amazon.co.uk titles disagree about ten millimetres.
You are in a UK garage with box section, a tile that needs a clean edge, or a bracket tucked into a corner, and the amazon.co.uk titles disagree about ten millimetres. This 115mm vs 125mm angle grinder page is only that choice, using the twelve listings in our angle grinder comparison, captured on 20 October 2026. The larger disc buys a little more depth. It does not buy a different kind of machine, and it does not belong on the smaller guard. Prices and weights come from those listings beside Screwfix’s published depth figures. Nothing here is a lab cut. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Disc class | Listed weight | Printed watts | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Bosch Professional Bosch Professional GWS 7-115 | 115 mm | 1.9 kg | 720 W | 8.6 | about £67.55 | View offer |
| Best value |  DCA DCA ASM18-115 | 115 mm | 1.67 kg | 860 W | 7.8 | about £29.99 | View offer |
| Alternative |  POSENPRO POSENPRO PPAG1200/125 | 125 mm | 2.51 kg | 1,200 W | 5.9 | about £33.99 | View offer |
On this page
What the two sizes change
UK shops still print 115 mm as 4.5 inch and 125 mm as 5 inch. The discs look close on the shelf. The depth is what changes the job. Screwfix’s buying guide, which we use as a rule of thumb rather than a measurement on your steel, puts cutting depth at about 30 mm for 115 mm and about 38 mm for 125 mm. A different UK article quotes about 35 mm for the larger class, and another shop guide says up to 40 mm. Plan with Screwfix’s pair. Treat 35 mm and 40 mm as other retailers’ figures.
Weight does not follow the diameter in a straight line. In this capture the DCA ASM18-115 is 1.67 kg and the Bosch Professional GWS 7-115 is 1.9 kg. CHANTPOWER, still a 115 mm tool, is 2.76 kg. A light 115 mm body is the better choice for overhead work or a tight flat when the cut stays under about 30 mm. A heavy 115 mm kit does not become a 125 mm grinder because it weighs more. Screwfix’s household bands describe how often you cut, not which disc reaches further. A 40 mm box section is already past the 30 mm guide, so a 115 mm disc means a second pass or a step to 125 mm. Watts come after that decision, on the angle grinder buying guide.
Which listings in this set are which
Six listings are 115 mm. DCA ASM18-115 is about £29.99 and 1.67 kg. CHANTPOWER is about £30.54 and 2.76 kg. DEKOPRO is about £25.99 and 2.44 kg. DEWINNER is about £29.74 and 2.61 kg. Bosch Professional GWS 7-115 is about £67.55 and 1.9 kg, and the class is taken from the part number. Bosch UniversalGrind is about £44 with a package weight of 2.66 kg. Watts and a diameter row are not printed there, so the class comes from the model name. Do not describe either Bosch as a measured 30 mm cut.
The other six are 125 mm. POSENPRO is about £33.99 and prints 1,200 W. LiunxDromic is about £44.64 and prints 1,000 W. The DCA cordless kit is about £56.98. SnowVolt, Kistrba, and YWNYT are bare bodies with no battery in the price. Kistrba’s highlight says 5 inch, which this set treats as 125 mm. That is a title claim, not a depth checked on a slab. If the real question is the socket rather than the disc, stop here. Battery and bare bodies are the corded vs cordless angle grinder page. A 125 mm cordless kit does not answer a shallow corded job that never leaves the garage socket.
Do not fit the larger disc to the smaller guard
These small grinders share a practical bore family, so a 125 mm disc can sit on a 115 mm spindle and still look installed. The guard is what stops that pairing, not the nut. HSE’s HSG17 describes the guard’s job on a portable grinder, including stopping an oversize wheel. Bosch Professional’s UK proper-use page says the wheel must stay within the tool’s capacity, and that you should not fit a worn wheel taken from a larger grinder. DTC’s disc guide adds that the diameter must match the grinder and the guard, and that the disc’s maximum speed must be at least the grinder’s no-load speed.
You are a few millimetres short of depth, the 125 mm disc from the drawer threads on, and the 115 mm guard no longer covers the wheel the way HSG17 expects. The motor may start. That is not a pass. Buy the disc that matches the guard, or buy the larger grinder. How to fit the guard you already have is on the how to use an angle grinder page.
Which to buy for a home job
Choose 115 mm for a flat, a shed, and cuts that stay under about 30 mm: a bolt, a tile score, a short piece of box section, a bracket you can reach from one side. The lighter bodies here, the DCA ASM18-115 and the Bosch GWS 7-115, make overhead or cramped work less tiring. The Bosch still needs a disc bought separately. CHANTPOWER at 2.76 kg is still the smaller class. Mass does not promote it to 125 mm.
Choose 125 mm when the cut is often near that 30 mm mark and you want the extra depth, about 38 mm on Screwfix’s guide. POSENPRO at about £33.99 and 1,200 W is the corded example in this set for that regular small job. A higher wattage still does not cancel a poor switch, and it does not turn the tool into a paving saw. A one-pass kerb or thick paving sits on Screwfix’s 230 mm line, about 70 mm. Hire or buy that machine outside this set. A higher wattage on a 115 mm tool can feel stronger in a shallow cut. It does not beat a 125 mm disc on depth.
Common questions
Is 125 mm worth it over 115 mm?
It is worth the step when your cuts often sit near 30 mm and you want the extra depth Screwfix puts at about 38 mm. It is a poor swap for a one-off bolt, a tile score, or work in a tight flat, where a lighter 115 mm body in this set is already deep enough. Ten millimetres of disc are that small gain in reach, and only when the guard matches the wheel.
How deep can each one cut?
Use about 30 mm for 115 mm and about 38 mm for 125 mm, taken from Screwfix as a rule of thumb. Other UK pages print about 35 mm or up to 40 mm for the larger class. Those are shop guides, not a cut on your steel. The Bosch GWS 7-115 takes its class from the part number, and the UniversalGrind takes it from the model name. Neither figure is a measured depth.
Which is lighter for overhead or tight work?
The DCA ASM18-115 is 1.67 kg and the Bosch GWS 7-115 is 1.9 kg, both 115 mm. CHANTPOWER, also 115 mm, is 2.76 kg, so the smaller class is not automatically the light one. For overhead work or a cramped corner, start with a lighter 115 mm body if the cut stays under about 30 mm. If you need the extra depth often, take the 125 mm tool and plan the stance, rather than forcing the larger disc under the smaller guard.
Can I fit a 125 mm disc on a 115 mm grinder?
No. The disc may sit on the spindle because these tools share a practical bore family, and the guard still cannot cover an oversize wheel. HSG17 and Bosch Professional’s proper-use page both refuse that pairing. DTC also requires the diameter to match the guard, and the disc’s rated speed to clear the grinder’s no-load speed. Buy a matching disc, or buy the larger grinder.
Do both sizes use the same bore and M14 nut?
They share the same practical bore family, which is why the wrong diameter can still thread on. That shared fit is not permission to mix sizes. The guard decides which disc is allowed. Match the disc to the capacity printed for that tool and to the guard fitted on it. A nut that tightens only shows that the thread engaged.
Do I need a 230 mm grinder for paving?
For a one-pass kerb or thick paving, yes. Screwfix puts that class at about 70 mm of depth, and none of the twelve listings here is a 230 mm tool. A 125 mm grinder covers cuts near 30 mm. It is not a substitute for that larger machine. Hire or buy the 230 mm tool outside this comparison.
Does a higher wattage on a 115 mm tool beat a 125 mm tool?
On a shallow cut it can, inside Screwfix’s bands of about 500–900 W for occasional 115 mm work and about 700–1,200 W for regular 125 mm work. It does not win on depth. A 900 W 115 mm grinder still follows the smaller wheel. Choose the diameter first, then the watts, and only among tools whose guard matches the disc you will fit.
Related pages
Sources
Public UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the twelve amazon.co.uk listings captured on 20 October 2026. HSE limits and PUWER apply at work. They are not a certificate for a domestic grinder, and none of these scores is a laboratory test.
- HSE, PUWER (retrieved 20 October 2026)
- HSE, HSG17 (retrieved 20 October 2026)
- HSE, vibration regulations (retrieved 20 October 2026)
- HSE, construction noise (retrieved 20 October 2026)
- Electrical Safety First, Angle grinders (retrieved 20 October 2026)
- Screwfix, Angle grinder buying guide (retrieved 20 October 2026)
- OPSS, PSA5 toothed saw blades (retrieved 20 October 2026)
- DTC, Cutting and grinding discs (retrieved 20 October 2026)