How many decibels is a subway train passing on the platform?

A subway train passing on the platform is typically around 95 decibels A-weighted, measured at a usual listening distance. That figure is a representative level rather than a measurement of any particular object, and the real level changes with distance, with the enclosure the sound is in, and with the specific equipment involved. Doubling your distance from a point source reduces the level by roughly 6 decibels.

What does A-weighted mean?

A-weighting is a filter applied to a sound level measurement that approximates how sensitive human hearing is at different frequencies. Human hearing is far less sensitive to very low frequencies than to mid frequencies, so an unweighted measurement overstates how loud a bass heavy sound seems. Almost every figure quoted in hearing conservation is A-weighted, which is why it is written dBA.

At what level does hearing protection become necessary?

The NIOSH recommended exposure limit begins at 85 decibels A-weighted averaged over an eight hour day. Above that, the permissible time halves for every 3 decibel increase, so 88 dBA allows four hours and 94 dBA allows one. The separate OSHA enforceable limit begins at 90 dBA and uses a 5 decibel exchange rate, which permits considerably longer.

Why are decibels not linear?

The decibel is a logarithmic ratio, which is why 20 decibels is not twice 10. An increase of 10 decibels corresponds to roughly a tenfold increase in sound intensity and is usually perceived as about twice as loud. The scale is logarithmic because the range of intensities human hearing covers is enormous, and a linear scale would be unusable.

Can I measure this myself?

Yes, with a sound level meter, which is an inexpensive handheld instrument. A phone app gives a rough indication and is useful for deciding whether a room is obviously loud, but a phone microphone is not calibrated and its reading should not be treated as a figure. If you are measuring to decide about hearing protection at work, the measurement that matters is a time weighted average rather than a peak.

How loud is a subway train passing on the platform

Quick answer

A subway train passing on the platform measures roughly 95 decibels A-weighted at a usual listening distance. That is at or above 85 dBA, where the NIOSH recommended exposure limit begins, and it allows about 47.6 minutes of exposure before protection is recommended.

How loud is a subway train passing on the platform compared with everything else?

Decibels are logarithmic rather than linear, which is why the numbers behave so unintuitively. An increase of 10 decibels is roughly a tenfold increase in sound intensity, and every 3 decibel increase halves how long the NIOSH recommended limit considers an exposure acceptable.

Published figure From a named standards body, regulator or professional classification. Reproduced here, not derived by us.

A subway train passing on the platform sits at about 95 dBA, alongside a petrol lawnmower, a hair dryer, a motorcycle at close range, a hand drill, a farm tractor, a nightclub dance floor.

Sounds at or near 95 dBA
Sound	Typical level (dBA)
A subway train passing on the platform	95
A petrol lawnmower	90
A hair dryer	90
A motorcycle at close range	95
A hand drill	98
A farm tractor	100
A nightclub dance floor	100

Typical A-weighted levels at a usual listening distance. Real levels vary with distance, enclosure and the specific equipment.

How long is 95 decibels safe for?

Published figure From a named standards body, regulator or professional classification. Reproduced here, not derived by us.

At 95 dBA the NIOSH recommended limit allows 47.6 minutes, while the more permissive OSHA enforceable limit allows a longer period.

Permissible exposure time at 95 dBA
Standard	Reference level	Exchange rate	Time allowed at this level
NIOSH recommended exposure limit	85 dBA over 8 hours	3 dB	47.6 minutes
OSHA permissible exposure limit	90 dBA over 8 hours	5 dB	not stated

These two standards are frequently quoted as though they were the same. They are not. NIOSH is a recommendation and OSHA is enforceable, and the 5 decibel OSHA exchange rate permits substantially longer exposure at the same level than the 3 decibel NIOSH rate does.

Common questions

How many decibels is a subway train passing on the platform?: A subway train passing on the platform is typically around 95 decibels A-weighted, measured at a usual listening distance. That figure is a representative level rather than a measurement of any particular object, and the real level changes with distance, with the enclosure the sound is in, and with the specific equipment involved. Doubling your distance from a point source reduces the level by roughly 6 decibels.
What does A-weighted mean?: A-weighting is a filter applied to a sound level measurement that approximates how sensitive human hearing is at different frequencies. Human hearing is far less sensitive to very low frequencies than to mid frequencies, so an unweighted measurement overstates how loud a bass heavy sound seems. Almost every figure quoted in hearing conservation is A-weighted, which is why it is written dBA.
At what level does hearing protection become necessary?: The NIOSH recommended exposure limit begins at 85 decibels A-weighted averaged over an eight hour day. Above that, the permissible time halves for every 3 decibel increase, so 88 dBA allows four hours and 94 dBA allows one. The separate OSHA enforceable limit begins at 90 dBA and uses a 5 decibel exchange rate, which permits considerably longer.
Why are decibels not linear?: The decibel is a logarithmic ratio, which is why 20 decibels is not twice 10. An increase of 10 decibels corresponds to roughly a tenfold increase in sound intensity and is usually perceived as about twice as loud. The scale is logarithmic because the range of intensities human hearing covers is enormous, and a linear scale would be unusable.
Can I measure this myself?: Yes, with a sound level meter, which is an inexpensive handheld instrument. A phone app gives a rough indication and is useful for deciding whether a room is obviously loud, but a phone microphone is not calibrated and its reading should not be treated as a figure. If you are measuring to decide about hearing protection at work, the measurement that matters is a time weighted average rather than a peak.

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Last updated 2026-09-17.