MP3 Bit Rate: What Does It Mean?

Bit rate meaning and which MP3 bit rate to use

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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 bitrate is only useful when space is at a minimum.

What Bit Rate Means

The bit rate of an MP3 file 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's been encoded with a constant bit rate (CBR) of 128 kilobits per second (kbit/s) is processed at 128,000 bits every single second. For audio that's 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 kbit/s. This is far higher than the best bit rate for MP3s, which is 320 kbit/s.

Does Bit Rate Matter?

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 all that much.

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:

  • Some detail might be missing in low bitrate MP3s.
  • You may not be able to hear subtle background tracks.
  • You might hear a small amount of distortion.

Use an audio file converter to change the bit rate of an MP3.

Here are some examples of how audio quality differs as bit rate increases:

  • 32 kbit/s: Usually used only for spoken audio
  • 96 kbit/s: Speech or low-quality streaming
  • 128 or 160 kbit/s: Mid-range bit rate quality
  • 192 kbit/s: Medium quality bit rate
  • 256 kbit/s: A commonly used high-quality bit rate
  • 320 kbit/s: The highest bit rate level that MP3 supports

Other audio file formats support much higher bit rates, such as up to 500 kbit/s for OGG files and 9.6 mbit/s for DVD audio.