An impact wrench is built around noise. Inside the nose, a spinning hammer strikes the anvil thousands of times a minute, and each blow is what turns a rusted lug nut that a ratchet cannot move. That is also why these tools sit near the top of the loudness scale in any garage or shop. The difference between models is still real, and it is worth knowing before you spend a day in a tire bay or under a truck.
Sixteen impact wrenches sold in the US carry maker noise declarations we could read and match to the US model. Thirteen of them are declared under the EN 62841 standards, and at the operator's ear they run from 91 to 101 dB(A). Three more, all from Milwaukee, have figures on pages that name no standard, from 95.4 to 99.79.
The test behind the numbers
Makers selling in Europe declare impact wrench noise under EN 62841-2-2, the part of the power tool standard that covers impact drivers and impact wrenches. 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, and every maker in this guide states a K of 3 dB.
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.
The makers name their standard in different ways. DEWALT, Makita and Bosch print EN 62841-2-2 next to the figures. Hilti's manuals say the EN 62841 standards apply and put the exact parts in the declaration of conformity. Milwaukee's European pages print the figures with no standard at all, so we keep them in a group of their own. Air impact wrenches are declared under a different family of standards, ISO 15744 and ISO 11148-6, and none is ranked here.
Almost none of it is printed for US buyers
Hilti is the exception. Its US pages print an A-weighted emission sound pressure level for each wrench, the same figure as in its European manuals, though not the sound power figure. For the other makers, none of the US product pages and US manuals we opened prints a noise figure. Every other number here comes from the same maker's European documents: DEWALT's UK manuals, Makita's EU manuals, Bosch's original instructions and Milwaukee's EU product pages.
Where the model number is the same in both markets, as with DEWALT's DCF891, DCF900 and DCF921 and Makita's corded TW0350, the match is direct, and DEWALT's UK and US manuals even print the same torque in newton metres. Makita's US manuals for the GWT02 and WT06 print specification tables that match its European TW002G and TW161D manuals line for line. Bosch's US and European versions share a part number family: the US GDS18V-740N carries 06019J8314, and the European GDS 18V-1000 manual gives 3 601 JJ8 3.., with the same three speeds. For Milwaukee we paired each US wrench with the European one of the same type, drive size, speeds and torque, and one pairing, the 2962-20, lists two of its four mode speeds differently in the two markets. Each catalog entry states the pairing and the evidence.
The ranking, declared under EN 62841
DEWALT's DCF891B leads at 91 dB(A) at the ear and 102 sound power. It is a mid-range 1/2 inch wrench with 600 ft-lbs of fastening torque and 800 ft-lbs of breakaway in DEWALT's US manual. Hilti's 12 V SIW 2-A12 follows at 92, with the lowest sound power here at 100, but it is a 3/8 inch subcompact rated for 133 ft-lbs.
Bosch's GDS18V-740N is third at 93.5, and it is a high torque wrench rated for 740 ft-lbs. DEWALT's DCF900B and Makita's 40V GWT02Z share the next spot at 95, with 1,030 and 1,250 ft-lbs of fastening torque.
Three wrenches declare 96: Makita's 12V max WT06Z, Hilti's 22 V SIW 4AT-22 and Makita's corded TW0350. DEWALT's DCF921B compact and Makita's 18V mid-torque XWT17Z declare 97, Bosch's GDS18V-330CN 98, Makita's 18V high torque XWT08Z 100, and Hilti's SIW 8-22 101, the highest figure in this guide.
Sound power follows a similar order, with some swaps. The SIW 2-A12's 100 dB(A) is lowest, then the Bosch GDS18V-740N at 101.5 and the DEWALT DCF891B at 102. DEWALT's compact DCF921B declares 108, four more than Hilti's compact SIW 4AT-22 at 104, although they are a decibel apart at the ear.
Milwaukee's European pages give sound pressure, sound power and a 3 dB(A) uncertainty for most of its wrenches, often to two decimal places. The M18 FMTIW2F12, the twin of the US 2962-20 mid-torque wrench, prints 95.4 dB(A) at the ear and 106.4 sound power. The M12 FSCIWF38, the twin of the 3049-20 subcompact 3/8 inch, prints 97 and 105. The M18 FIW2F12, the twin of the 2855-20 compact 1/2 inch, prints 99.79 and 110.79.
The pages do not describe the test behind these figures, and we cannot compare test setups that are not described. That is the reason these three stay in their own group. None of them would change who is quietest overall: the DEWALT DCF891B declares 91 dB(A) under EN62841-2-2, four decibels under Milwaukee's lowest.
3/8 inch and 12 V wrenches
Small wrenches are not automatically quiet. Among the 3/8 inch tools, Hilti's SIW 2-A12 declares 92 dB(A), DEWALT's DCF923, the 3/8 inch sibling of the DCF921B, declares 96 in the same UK manual, and Milwaukee's M12 3049-20 prints 97. On 12 V batteries, Makita's WT06Z is the only 1/2 inch drive here, at 96. If most of your work is small fasteners, the lightest tool is not always the quietest one, so check the figure before you buy.
Torque and noise
A bigger wrench is not always a louder one. The Bosch GDS18V-740N declares 93.5 dB(A) with 740 ft-lbs, less than every compact 1/2 inch wrench here. Makita's GWT02Z declares 95 with 1,250 ft-lbs, five decibels under its own 18V XWT08Z, which is rated for 740. But Hilti's SIW 8-22, a high torque 1/2 inch, declares the most at 101. The design of the hammer mechanism, the housing and the motor seem to matter as much as the torque rating, and each wrench has to be judged on its own figure.
The silent aisle
Milwaukee's EU page for the M18 FHIW2F12, the European version of the US 2967-20 high torque wrench, lists torque and speed but no noise values, and neither does the page for the M12 FCIWF38G3, the European version of the 2562-20 stubby. So those two popular Milwaukee wrenches are not ranked. DEWALT's UK page for the DCF961 high torque wrench links no manual we could open, and we found no European twin with figures for Bosch's GDS18V-221N. These wrenches may be quiet or loud. Their makers' documents that we read do not say.
What the spread means
Ten decibels separate the quietest declaration here from the loudest at the ear. That is a large gap on a logarithmic scale, but even at 91 dB(A) the Makita, Bosch and DEWALT manuals all tell you to wear hearing protection. In use, a seized bolt, a long socket extension or the echo of a metal building can change what you actually hear. Choosing a quieter wrench helps, and so does using the lowest power mode that does the job, which many of these wrenches offer.
We did not measure any of these impact wrenches. Every figure is the maker's own, quoted as published, with the standard, K value and document identified wherever the maker identified them.
