How Loud Is a Lawn Mower?

NIOSH puts a lawn mower at 85–90 dBANIOSH.

That is not an incidental figure. Eighty-five is the level at which every American hearing-health document changes character, and a mower sits at the bottom of its own range exactly there — which makes an ordinary Saturday chore the most common way people meet the threshold at all.

What else sits in that band

The company a mower keeps is the useful part of that table. Power tools, a printing press and a vacuum cleaner are all published in the same bandNIOSH. None of them feels dangerous, and that is precisely the problem: at this level the risk is a function of how long you stay, not of how bad it sounds.

There is a check that needs no equipment. At 85 dBA you generally have to raise your voice to be heard by someone three feet awayNIOSH. If you find yourself doing that behind the mower, the published figure is describing your machine well enough.

How long is a mow safe

At the bottom of the published band, 85 dBA, the NIOSH model allows eight hoursNIOSH. Nobody mows for eight hours, so a single lawn is comfortably inside it.

At the top of the band the picture changes faster than the five-decibel gap suggests, because the allowed time halves for every 3 dB increaseNIOSH. Ninety decibels is more than three decibels above the criterion, so the allowance is under half the day rather than a full one — still far more than a lawn takes.

The caveat matters more than the arithmetic here. The NIOSH limit is an occupational one, and NIOSH says directly that it is not a recommendation for noise in the general environment, and that it assumes the other sixteen hours of the day are spent somewhere quieterNIOSH. A landscaper mowing all day is the case the limit was written for. Someone doing their own lawn is borrowing it, and the borrowing runs in the conservative direction.

Why your mower is not the published number

Published figures are ranges for a category of machine, not values for yours. Two things move a real reading around more than most people expect.

The kind of machine. A petrol engine and a battery-powered motor are not the same acoustic object at all, and a ride-on is not a walk-behind. NIOSH's band covers a category broad enough to contain all of them, which is why it is published as a range rather than a point.

Distance and position. The published figure is taken near the machine, and almost no published value states from where. A mower heard from a neighbouring garden is a completely different number from the same mower behind the handles, and the level at the operator's ear is what any of this guidance is about.

Which is to say: if you want to know about your mower, the published band tells you what region to expect and nothing more precise than that.

Checking yours

The online decibel meter on this site runs in the browser — hold the phone where your head is while mowing, let the reading settle, and take where it sits rather than what it touches.

The number will be an uncalibrated estimate. Sound apps have been found to scatter by roughly ±10 dB against a reference instrumentKardous & Shaw, and a browser has less to work with than a native app. What it is good for is the comparison: your mower against your vacuum, this year's machine against last year's, or the difference an ear defender makes when you hold the phone inside one.

For contrast, sound at or below 70 dBA is unlikely to cause hearing loss however long it lastsNIDCD. If your reading lands there, the question is closed. If it lands in the eighties, the duration is what decides it.

Petrol, battery, ride-on

The category NIOSH's band covers is broad, and the differences inside it are real even though no agency publishes a figure for each type.

A petrol engine produces its noise continuously and across a wide range of frequencies; a battery motor is generally quieter and more tonal, and a ride-on puts the engine closer to the operator for longer. None of that changes what the published band says, and none of it can be resolved by reading more charts — it is exactly the situation where taking your own reading beats looking one up, because the question is about a specific machine rather than a category.

What can be said generally: the level at your ear depends on where the engine is relative to your head, and that varies more between machine types than most of the acoustic differences do. A walk-behind puts the source below and in front. A ride-on puts it underneath you.

What the neighbours hear

A different question, and one the occupational figures answer badly.

The published band describes the level near the machine. Someone in the next garden is hearing something considerably quieter, and the relevant thresholds for them are not about hearing damage at all — sound at or below 70 dBA is unlikely to damage hearing however long it lastsNIDCD, and most mower noise arriving next door is below that.

That does not make it acceptable, and it does not make a complaint unreasonable. It means the complaint is about annoyance, quiet enjoyment and the hour of the day rather than about hearing loss, and the rules that apply are local ones about permitted hours rather than any figure on this page.

How long does mowing a lawn actually take

Worth putting next to the allowance, because the answer is usually reassuring.

Most domestic lawns are twenty minutes to an hour. Against an allowance of eight hours at the bottom of the published band, that is a small fraction of a day — even at the top of the band it stays a fraction. The mower is not the thing that will spend your day.

What can spend it is a Saturday where the mower is one of four machines. An hour of mowing, then a strimmer, then a chain saw, then an afternoon at a match, is a sequence where each item looks harmless and the sum does not. That is what a dose is for, and it is the only honest way to look at a day built out of several loud tasks rather than one.

What to actually do about it

Ear defenders or plugs for the mow, which is a decision that takes ten seconds and covers the whole range the machine could be in. NIOSH's advice for anyone outside a workplace is that a level of 85 dB(A) or higher is a reason to take precautions regardless of whether you know the averageNIOSH, and a mower's published band starts exactly there.

Beyond that: less time per session rather than one long one, and distance from anything else running at the same time. A strimmer going while the mower runs is not five decibels added — it is a second source, and the decibel scale does not add the way arithmetic does.

Nearby questions

Vacuum cleaner noise is published in the same band as a mower and is met far more often — that is vacuum cleaner noise.

At the other end, motorcycle decibels covers a source NIDCD publishes across a much wider range, where the top of the band is a different kind of problem entirely.