MP3 Bit Rate: What Does It Mean?

mp3 car aux
Plugging in an MP3 player or phone via an auxiliary input is one way to go, but it may not provide the best sound. PraxisPhotography / Moment / Getty

MP3 is a popular digital audio coding format. When looking at the bit rate of an MP3, typically the larger the bit rate, the better the sound quality. A lower bit rate is only useful when space is at a minimum. 

About Bit Rate

In an MP3, bit rate is a measure of the audio data throughput in a given amount of time. Simply put, it's the number of bits that are processed every second. For example, the audio data in an MP3 file that has been encoded with a constant bit rate (CBR) of 128 kilobits per second is processed at 128,000 bits every second. For audio that has been encoded at a variable bit rate (VBR), the displayed value is an average.

The higher the bit rate, the better the sound quality when playing back a lossy audio format tune. To put digital audio compression into perspective when talking about bit rates, a standard audio CD, which contains uncompressed audio data, has a bit rate of 1,411 Kbps. This is far higher than the best bit rate for MP3s, which is 320 Kbps.

How Bit Rate Affects You

Unless you consider yourself an audiophile and have a top-notch pair of headphones to wear while listening to your music, the bit rate of your MP3s may not matter. If you're wearing inexpensive earbuds with your iPod, you won't be able to hear the difference in your music. Even with premium headphones, the difference between high and low bitrates is most noticeable in only a few areas: a little of the detail may be missing in low bit rate MP3s, you may not be able to hear subtle background tracks, or you might hear a small amount of distortion.