In this guide
Audio bitrate describes how many bits encode a second of audio, usually expressed in kbps. A higher rate generally means a larger file, but codec, source quality and encoding choices also matter. Compare actual exports instead of treating bitrate as a quality score.
Audio bitrate is the amount of data used to represent audio over time. It is commonly shown in kilobits per second (kbps). A 192 kbps audio stream uses about 192,000 bits per second on average; at a constant rate, that is approximately 1.44 MB of audio data per minute, before container and metadata overhead.
Bitrate is useful for planning file size and bandwidth. It is not a complete measure of sound quality: the codec, encoder, source, channel arrangement and material all matter. Compare exports from the same original at similar listening levels and check the destination's requirements.
How bitrate affects file size
For a constant bitrate, estimate the audio payload with duration in seconds × bitrate in kbps × 1,000 ÷ 8. This gives bytes. Divide by 1,000,000 for decimal MB. The finished file can be larger because of tags, framing and container overhead.
| Audio bitrate | One minute, estimated payload | Ten minutes, estimated payload |
|---|---|---|
| 128 kbps | 0.96 MB | 9.6 MB |
| 192 kbps | 1.44 MB | 14.4 MB |
| 320 kbps | 2.40 MB | 24 MB |
These are estimates for the audio stream, not guarantees for a whole video file. Video, additional audio tracks and container overhead add data. For a variable-bitrate file, use its average audio bitrate for an estimate and inspect the actual file for a strict size limit. The audio file size calculator helps compare other durations and rates.
Does higher bitrate mean better audio?
For the same lossy codec, encoder and source, a higher bitrate generally gives the encoder more data to represent the sound, but it does not guarantee an audible improvement. Speech, cymbals, ambience and dense music challenge an encoder differently. A lower-rate file from one codec is not automatically worse than a higher-rate file from another. Codec capabilities and settings differ; see MDN's audio codec guide.
A noisy recording remains noisy at a high bitrate, and converting a low-bitrate MP3 to a higher bitrate cannot restore the information discarded earlier. Keep the best available original and make each comparison from that source. MP3 and AAC are lossy; FLAC is lossless. Lossless encoding preserves the encoded samples, but cannot restore detail already missing from its source.
Bitrate vs sample rate vs bit depth
| Property | What it describes | Example |
|---|---|---|
| Bitrate | Data per second in an audio stream. | 192 kbps MP3 |
| Sample rate | Samples per second per channel in digital audio. | 48 kHz means 48,000 samples per second per channel. |
| Bit depth | Bits used to represent each sample in integer PCM. | 24-bit PCM has a different sample representation from 16-bit PCM. |
For uncompressed integer PCM, audio payload bitrate equals sample rate × bits per sample × number of channels. For example, 48,000 Hz × 16 bits × 2 channels is 1,536,000 bits per second, or 1,536 kbps. That does not mean a 1,536 kbps PCM file and a 1,536 kbps lossy file are interchangeable. WAV is a container that can hold different encodings; inspect the actual file rather than assuming every WAV is PCM. The WAV file inspector can help inspect supported local WAV files.
Constant, variable and average bitrate
Constant bitrate (CBR) aims for a fixed rate and makes duration-based size estimates straightforward. Variable bitrate (VBR) allows the encoder to use different rates across the audio. Average bitrate (ABR) targets an overall average while allowing variation. Exact behavior depends on the encoder and format. Audacity's MP3 export options explain these choices for MP3.
A displayed bitrate may be a target, an average or a stream property. A video's overall bitrate may also include picture and other tracks, so it should not be mistaken for the audio track's bitrate. Check the specific audio stream in your editor or media inspector.
How to choose a bitrate
- Start with the destination. Check accepted codecs, bitrate or file-size limits, and whether the recipient needs an editable lossless file.
- Keep a suitable master. Preserve the original or a lossless working copy when available; avoid repeatedly encoding lossy files during editing.
- Choose a representative excerpt. Include quiet speech and consonants, or dense music and cymbals, depending on your project.
- Export candidates from the same source. Use the same codec and encoder when comparing rates. Listen at similar volume and check the actual size.
- Verify the delivered file. Play it on the intended device and confirm any platform or collaborator requirements.
For an MP3-specific comparison, see 128, 192 and 320 kbps MP3. For live streaming, the OBS audio bitrate guide explains track settings and checks. Neither number alone guarantees a particular result.
Common questions
Is 320 kbps lossless?
No. A 320 kbps MP3 is still lossy. Losslessness depends on the encoding, not a bitrate threshold.
Is kbps the same as kHz?
No. Kbps describes bits per second; kHz describes thousands of samples per second. They measure different properties.
Does converting 128 kbps MP3 to 320 kbps improve it?
It makes a new, usually larger lossy file but cannot recover information lost in the first encode. Use the original master when available.
Does stereo double the size?
At the same total constant bitrate and duration, mono and stereo encoded streams have approximately the same payload size. In uncompressed PCM, doubling channels doubles the sample payload if sample rate and bit depth stay fixed.