Audio File Size Calculator
PCM audio MB, bitrate, and GB hours.
What it does
Uncompressed audio size is arithmetic. Sample rate times bit depth times channels times seconds gives bytes, with no codec tricks. CD audio at 44.1 kHz, 16 bit, stereo runs near 10 MB a minute, so albums need hundreds of megabytes before compression.
The tool above runs PCM math. Three minutes of CD audio gives 31.8 MB at 1411.2 kbps with 1.57 hours per GB. One hour at 48 kHz, 24 bit, stereo gives 1036.8 MB at 2304 kbps with 0.96 hours per GB. Higher rates and depths cost storage linearly.
Bitrate and size stay linked. Doubling channels doubles both, while halving time halves both. Compressed formats break the link with ratios of their own, so MP3 and FLAC sit below these PCM ceilings.
This page models PCM only. It does not estimate MP3, AAC, or FLAC sizes, nor headers and streaming overhead. Use it to size masters before encoding.
How to use
- Enter the duration in seconds.
- Pick 44.1, 48, or 96 kHz.
- Pick 16 or 24 bit.
- Pick mono or stereo.
- Read MB first, then bitrate.
- Read hours per GB for storage planning.
Formula
- secs
- Duration in seconds.
- rate
- Samples per second in kHz: 44.1, 48, or 96.
- bits, ch
- Bits per sample with channels 1 or 2.
Uncompressed PCM with 44.1, 48, or 96 kHz and 16 or 24 bit in mono or stereo. At zero seconds there is no file. Compressed formats need their own ratios.
Worked example
Example: 3 min CD audio
Defaults: 3 minutes of CD audio (44.1 kHz, 16 bit, stereo). Uncompressed PCM only.
- Inputs: 180 s at 44.1 kHz, 16 bit, stereo.
- Bytes: 44100 times 2 times 2 times 180 is 31,752,000.
- MB: /1,000,000 is 31.8 MB.
- Bitrate: 44100 times 16 times 2 / 1000 is 1411.2 kbps.
- Hours per GB: 1.57 h per GB. Tool shows the same.
Reference table
| Format and time | Size | Bitrate |
|---|---|---|
| 44.1/16/stereo 180 s | 31.8 MB | 1411.2 kbps |
| 48/24/stereo 3600 s | 1036.8 MB | 2304 kbps |
| 96/16/mono 60 s | 11.5 MB | 1536 kbps |
| 44.1/16/mono 60 s | 5.3 MB | 705.6 kbps |
| 48/16/stereo 180 s | 34.6 MB | 1536 kbps |
Limits
- PCM only. Compressed formats excluded.
- Headers ignored. Small overhead extra.
- No streaming overhead.
- Fixed rate assumed. Variable rates differ.
Common mistakes
- Reading MB as MiB (2% gap).
- Pricing MP3 from PCM math.
- Forgetting stereo doubles size.
- Mixing kHz with Hz, off by 1000x.
- Ignoring headroom for masters.
Try it yourself
Quick checks. Answers sit tucked under each question.
1 hour at 48 kHz, 24 bit, stereo?
Bytes are 48,000x3x2x3600 = 1,036,800,000, or 1036.8 MB at 2304 kbps with 0.96 h per GB.
1 minute at 96 kHz, 16 bit, mono?
Bytes are 96,000x2x1x60 = 11,520,000, or 11.5 MB at 1536 kbps with 1.45 h per GB.
Questions
How is audio size figured?
Bytes = rate x bits/8 x channels x seconds, /1e6 for MB. Here 31.8 MB.
How is bitrate figured?
Rate x bits x channels / 1000. Here 1411.2 kbps.
How are hours per GB figured?
1e9 / bytes per hour. Here 1.57 h per GB.
Is this my MP3 size?
No. MP3, AAC, and FLAC shrink below PCM. This is the uncompressed source size.
Do stereo and time scale linearly?
Yes. Double channels doubles size. Halve time halves it.
Does this include headers?
No. Headers add a little. Streaming adds overhead on top.