What is bitrate in audio?

Bitrate is the number of bits processed per second in an audio stream, measured in kilobits per second (kbps). Higher bitrates mean better audio quality and larger file sizes. Common MP3 bitrates range from 64 kbps (low quality) to 320 kbps (near-lossless).

Is the calculated size exact?

The result is an estimate based on a constant bitrate (CBR). Variable bitrate (VBR) files will differ slightly because the bitrate changes with audio complexity. Container overhead (ID3 tags, headers) also adds a small amount — typically under 1% for files longer than a minute.

What bitrate should I use for MP3?

128 kbps is acceptable for casual listening, 192 kbps is a good balance of quality and size, 256–320 kbps is recommended when quality matters. Lossless formats like FLAC use 700–1400 kbps depending on source material.

How do I calculate audio file size manually?

Multiply the bitrate in kbps by the duration in seconds to get total kilobits, then divide by 8 to convert to kilobytes. For example, a 3-minute track at 320 kbps: 320 × 180 ÷ 8 = 7,200 KB ≈ 7.03 MB.

Does audio format affect the calculation?

This calculator works for any constant-bitrate format (MP3, AAC, OGG, WMA, etc.). For lossless formats like WAV or AIFF, multiply sample rate × bit depth × channels to get the bitrate first, then use this tool.

Audio File Size Calculator

Name: Audio File Size Calculator
Availability: InStock
Author: Nham Vu

Enter a bitrate and duration to instantly calculate the expected audio file size in KB, MB, and GB.

Audio Parameters

Bitrate (kbps)

Duration

Hours

Minutes

Seconds

Estimated File Size

Fill in the bitrate and duration, then click Calculate.

Common Bitrate Reference

Bitrate	Quality	Typical Format	Size / min
64 kbps	Low	Podcast, Voice	0.47 MB
96 kbps	Medium-low	Internet Radio	0.70 MB
128 kbps	Standard	MP3, AAC	0.94 MB
192 kbps	Good	MP3, AAC	1.40 MB
256 kbps	High	AAC, MP3	1.88 MB
320 kbps	Near-lossless	MP3 max	2.34 MB

Summary

Enter a bitrate and duration to instantly calculate the expected audio file size in KB, MB, and GB.

How it works

Enter the audio bitrate in kilobits per second (kbps) — common values are 128, 192, 256, or 320 kbps for MP3.
Enter the duration using the hours, minutes, and seconds fields.
The calculator multiplies bitrate by total seconds to get total bits, then converts to bytes.
Results are displayed instantly in KB, MB, and GB.
Use the preset bitrate buttons to quickly fill in common values.

Use cases

Estimate how much storage a podcast episode will require before recording.
Calculate the download size of a music album at a given quality setting.
Plan disk space for long audio recordings such as lectures or interviews.
Compare file sizes across different bitrates to choose the right quality/size trade-off.
Estimate streaming bandwidth needs for online audio content.
Check how many audio files will fit on a device with limited storage.
Verify expected file size before downloading a large audiobook.
Help clients understand the storage impact of different audio quality levels.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu