Laptop makers are some of the best acoustic disclosers anywhere. Apple, Dell, HP and Lenovo declare noise for current models under ISO 7779, ISO 9296 and ECMA-74 or ECMA-109, the same standards behind our mini PC guide, and they publish the declarations in support pages, regulatory datasheets and ECO declarations.
Seventeen current US laptops carry those declarations. At idle they run from 1.2 bels of sound power for a fanless MacBook to 2.8 bels for the flagship ThinkPad.
Two conventions that must not mix
The makers do not declare the same statistic. Apple and Dell print the mean sound power, LWA,m, with a statistical adder, KV, in its own column. HP and Lenovo print a statistical upper limit, LWA,c or LWAd, with the adder already included. A Lenovo 2.5 is not louder than a Dell 2.2 by 0.3 bels; they are different kinds of number.
Apple's footnote explains the relationship: KV is the adder for computing the upper limit from the mean. We rank Apple and Dell against each other, and HP and Lenovo against each other, and flag which convention each figure uses. The sound power vs sound pressure explainer covers bels, KV and the rest.
The Macs, with and without fans
Apple's declarations are strikingly uniform: every current MacBook declares 1.2 or 1.3 bels at idle and on its wireless web test, with 3 or 4 dB at the operator position. The MacBook Neo and MacBook Air are fanless, by Apple's own statements, so their figures are the measurement floor.
The MacBook Pro 14 with M5 has a fan and declares the same 1.3 bels. At light loads its fan adds nothing measurable. Apple declares no full load mode, though, so how loud a MacBook Pro gets under a long render is not published.
Windows laptops
On the mean convention, Dell's 14 Plus leads Windows laptops at 2.2 bels and 14.1 dB, and it declares the same figures under disk access as at idle. Dell's premium machines do not beat it: the Pro 14 Premium declares the same 2.2 bels with 22.0 dB of sound pressure, and the XPS 13 comes in at 2.5 bels.
On the upper limit convention, HP's EliteBook X G2i 14 declares 2.2 bels and 14 dB at idle, the lowest Windows figure on that scale, though its configured price on HP's store runs past $6,000. Lenovo's ThinkPads declare 2.5 to 2.8 bels at idle, and Lenovo is the only maker publishing a processor load figure: the T14s Gen 7 holds 26.7 dB with the CPU working.
Oddities in the paperwork
Dell publishes two XPS 13 datasheets with the same sound power and sound pressure figures 8 dB apart. Its XPS 14 and XPS 16 declare identical numbers. None of these change the ranking, but they are a reminder that a declaration is a document, and documents have errors.
Who publishes nothing
Microsoft's Surface eco profile has no acoustic row. We found no declaration from Framework or ASUS, or for HP's consumer OmniBook and Spectre lines. We did not confirm current Acer models either way.
We did not measure any of these laptops. Every figure is the maker's own, quoted as published, with the standard, mode, position and KV wherever the maker gave them.
