What does 65 dB sound like? Everyday noise levels compared

A decibel figure on its own means little until you can hear it in your head. The easiest way is to place it between sounds you know.

What 65 dB sounds like

A normal conversation at about 1 m is around 60 dB. A washing machine, or a vacuum cleaner a few metres away, is around 70 dB. 65 dB sits between the two. The Australian government's aircraft noise assessments put ordinary conversation at about 60 to 65 dB, so a sound at 65 dB is as loud as the voices it competes with: you can talk over it, but you have to raise your voice or wait for it to pass.

A single sound at 65 dB is harmless and, on its own, easy to ignore. What makes it matter near an airport is repetition: dozens or hundreds of times a day, each one long enough to stop a sentence.

Everyday noise levels compared

These are typical levels from the FAA and the Australian government. A sound's level depends on how far away you are, which is why some come with a distance.

For planes, the level depends on the aircraft, its height and how far to the side it passes; how loud a plane is over a house gives measured figures.

How the decibel scale works

Decibels are logarithmic: each step up means a multiple of the sound energy, not an extra amount of it, which matches the way our ears respond. Three rules cover most of what you need:

• 3 dB more doubles the sound energy. Two identical machines running side by side measure 3 dB more than one.
• 10 dB more sounds about twice as loud. A vacuum cleaner at 70 dB sounds roughly twice as loud as a conversation at 60 dB.
• 2 to 3 dB is about the smallest change most people notice.

So 65 dB carries about three times the energy of 60 dB, but sounds only about 1.4 times as loud. The same arithmetic explains why official noise averages move so little: doubling the number of flights over a day adds just 3 dB to the average, a change most people could barely hear, while the number of planes has doubled.

Why 65 dB matters

A threshold like 65 dB is about speech. Australia counts aircraft noise events above 70 dB outdoors (N70), because a plane at that level makes about 60 dB inside a room with the windows open, enough to disturb a conversation. At night the count is of events above 60 dB (N60): about 50 dB indoors with the windows open, close to the level at which a sleeping person may wake.

The UK settled on 65 dB for daytime counts. The CAA's 2014 Survey of Noise Attitudes recommended counting planes above 65 dB (N65) rather than 70 dB, because in many areas flights were already quieter than 70 dB on the ground, and fleets keep getting quieter. The government's 2017 air navigation guidance then required proposals for new flight paths to consider N65 by day and N60 at night, and to use them to show communities the likely effect. Heathrow's annual noise report still maps N65 around the airport.

Indoors and outdoors

All these thresholds are outdoor levels. Walls and windows take some of the sound off: Australian assessments assume about 10 dB with the windows open and 20 dB with them closed, and Germany's aircraft noise law allows 15 dB between outside and inside when it draws its night-time protection zones.

So a plane at 65 dB outside is roughly 55 dB in a room with an open window. That is still well above the background: a monitor at Shepperton, near Heathrow, measured about 45 dB of background noise through the day and about 40 dB between midnight and 4 a.m.

Is 65 dB harmful?

It is far below the levels that hearing rules deal with. UK workplace rules require employers to act when a worker's average exposure over a day reaches 80 dB (A-weighted), or when sudden peaks reach 135 dB (C-weighted); 65 dB is far below both. The effects researched near airports are annoyance, disturbed sleep and long-term health, and they are studied with averages over the day and night. The World Health Organization recommends keeping aircraft noise below 45 dB Lden over the day and 40 dB Lnight at night. What the research says about living near an airport covers the studies.

Why we count planes above 65 dB

An average over the day hides how many planes there were; counting loud planes explains why. So our reports count them: a plane is loud when it passes 65 dB outdoors.

The count tracks how people feel. The CAA's survey of nearly 30,000 people around ten UK airports in 2023 found that the share highly annoyed by aircraft noise rose with the number of planes above 65 dB on an average summer day: about 12% where there were none, 25% at 50 a day, 34% at 100 and 39% at 200.

On our sample report for Kew Green, 10 km from Heathrow, that is 66 loud planes on an average day and 11 on an average night.