An angle grinder is loud in a different way from a saw. The motor spins a 4-1/2 or 5 inch wheel at up to 11,000 RPM, the gears whine, and the wheel itself screams against steel, stone or tile. A cut-off job can be over in seconds, but grinding down a weld or cleaning up a rusty frame keeps the tool running for many minutes, often inches from your head.
Twelve 4-1/2 and 5 inch grinders sold in the US carry maker noise figures we could read and match to the US model. Eight of them form the main group: A-weighted figures under the current standard, plus three Milwaukee figures whose EU pages name no standard. At the operator's ear those run from 82 to 85 dB(A). Two corded Makitas have figures only under an older standard, and two Fein grinders print theirs in a way we keep apart.
The test behind the numbers
Makers selling in Europe declare grinder noise under EN 62841-2-3, the standard for handheld grinders, polishers and disc sanders. It gives two quantities. LpA is sound pressure at the operator's position. LWA is sound power, the tool's total output. Each comes with a K value, the uncertainty, which is 3 dB for every grinder here.
We rank on LpA and show LwA beside it. Both come from the same test, but they measure different things and never belong in one ranking. The sound power vs sound pressure explainer covers why.
Three more rules shape the ranking. Figures under the older EN 60745 standard are ranked only against each other. Figures printed as "dB" without "(A)" are kept apart from A-weighted ones. And where a maker gives separate figures for different applications, such as surface grinding and sanding with a disc, we would not rank one against another; every noise figure we quote here is a single declared value for the tool.
Almost none of it is printed for US buyers
Of the brands we checked, only Fein prints noise figures on its US grinder pages. None of the Makita, Milwaukee, Bosch or DEWALT US pages or manuals we opened prints one, and every other figure here comes from the same maker's European documents: Makita's EU manuals, Milwaukee's EU product pages, Bosch's European original instructions and DEWALT's UK service site.
Where the model number is the same in both markets, as with the Makita 9557PB and GA4530 and the DEWALT DCG413, the match is direct. Bosch makes its tools easy to check through shared part number families: the US GWX18V-10PN is part 06019J4212, and the European GWX 18V-10 P is 0 601 9J4 200, both rated at 9,000 RPM. For Makita's cordless grinders and Milwaukee's M18 FUEL grinders we paired each US tool with the European one that has the same speed range, switch type, brake and wheel size. Each catalog entry states the pairing and the evidence. One caveat applies to the two corded Makitas: their declarations describe the 230 V European tools, and the US versions run on 120 V.
The main group
The quietest grinder in the main group is also one of the plainest. Makita declares 82 dB(A) at the ear and 90 dB(A) sound power for the DGA504, the twin of the US XAG04Z: a brushless 18V LXT grinder with a lock-on slide switch and no electric brake. Both figures are the lowest in the main group.
Milwaukee's M18 FUEL grinders sit just behind. The EU pages for the braking slide switch M18 FSAG125XB and the variable speed paddle switch M18 FSAGV125XPDB, twins of the US 2881-20 and 2888-20, both print 82.6 dB(A) at the ear and 93.6 sound power. The flathead M18 FSAGF125XPDB, the twin of the 2886-20, prints 82.67 and 93.67. None of the three pages names a standard or a test condition, which is why we say so each time we quote them.
Makita's paddle switch XAG20Z, through its twin the DGA517, declares 83 dB(A) and 91 sound power. That puts it 0.4 decibels above the Milwaukee 2888-20 at the ear but 2.6 below it on sound power, the lowest of any paddle switch grinder in the main group. Bosch's X-LOCK GWX18V-10PN declares 84 and 92, and its threaded GWS18V-10PN 85 and 93, the same pair as DEWALT's DCG413B.
The whole main group spans three decibels at the ear. That is a real difference if you grind all day, but it is far smaller than the difference between grinding thick plate and thin sheet.
Two corded grinders on the older standard
Makita's corded 9557PB and GA4530 have declarations only under EN 60745, the older standard: 85 dB(A) at the ear and 96 sound power for each. We rank them against each other, where they tie, and not against the cordless grinders. Makita's newer European GA4530R, a different model declared under EN62841-2-3, gives 88 dB(A) at the ear and the same 96 sound power, which is reason enough to keep the two standards apart.
Fein, printed without the A
Fein puts figures on its US pages, which no other brand here does. The CCG 18-125-10 AS and the dead man's switch CCG 18-125-10 PD AS both list "Sound pressure level LpA" 86 dB and "Sound power level LWA" 97 dB, each with a K of 3, and a "Peak sound value LpCpeak" of 99 dB. The pages print "dB" rather than "dB(A)" and name no standard, so we list the two Fein grinders on their own rather than rank them against the others.
The silent aisle
DEWALT prints no noise figure on the US page or in the US manual for its corded DWE402, and we found no UK tool with that model number to quote. We also found no UK DCG415, and DEWALT's US page for the DCG405B no longer loads, so neither is ranked. Milwaukee's EU pages for its M18 FUEL high performance grinders, the M18 FHSAG125XB2 and M18 FHSAG150XB2, list speed and disc size but no noise values.
Some grinders have European relatives we could not call twins. Makita's EU manual declares 84 dB(A) for the 40V max GA005G, but at 9,000 RPM, where the US GAG01Z runs at 8,500. It declares 87 dB(A) for the 6 inch 9566PC at 10,000 RPM, where the US tool runs at 9,000. We found no EU manual under the number of Makita's corded X-LOCK GA4570. Hilti's US page and manual for the AG 4S-22 print no figure; its UK page and European manual for the AG 4S-22-125 give 89 dB(A) at the ear, and the manual 97 sound power under 62841-2-3:2021, but the UK tool's six speed steps run from 3,400 to 7,600 RPM and the US tool's from 3,100 to 7,700. Metabo's international page gives 96 dB(A) for the corded WEV 11-125 Quick, but its US pages returned errors or a blank landing page when we checked, so we could not match a US model. These grinders may be quiet or loud; we cannot rank them fairly.
What the spread means
At the ear, the eight main group grinders sit within three decibels of each other. The choice of wheel, the material and how you hold the work matter at least as much. Makita's and Bosch's manuals warn that thin sheet metal can push noise up to 15 dB above the declared value, far more than the three decibel spread in the main group. Clamp the work, damp large panels, let the wheel do the cutting, and wear hearing protection whichever grinder you own.
We did not measure any of these grinders. Every figure is the maker's own, quoted as published, with the standard, K value and document identified wherever the maker identified them.
