Audio Bitrate & File Size Calculator
Solve for file size, required bitrate, or recording time from format, bitrate, sample rate, bit depth, channels, and duration.
What this tool tells you
What it does
Calculate average audio bitrate from file size and duration, estimate file size from bitrate and duration, or estimate recording time from available storage. File size in bytes = bitrate in bits per second × duration in seconds ÷ 8; average bitrate reverses this formula.
How to use it
For average bitrate, enter file size and duration. For file size or recording time, WAV and AIFF use sample rate, bit depth, and channels; FLAC uses those settings with an approximate size factor. MP3, AAC, and OGG use the total bitrate you enter in kbps, not a per-channel rate.
How to interpret it
Uncompressed PCM bitrate = sample rate × bit depth × channels: 44,100 Hz × 16 bits × 2 channels = 1,411.2 kbps. FLAC is estimated at 60% of raw PCM size, not a fixed bitrate or guaranteed saving. Lossy variable-bitrate output and container metadata can change actual file sizes. Size inputs labeled MB and GB use 1,024-based units.
Frequently Asked Questions
- How is file size calculated?
- Estimated size in bytes = bitrate in bits per second × duration in seconds ÷ 8. For uncompressed WAV and AIFF, bitrate = sample rate × bit depth × channels. For MP3, AAC, and OGG, the entered kbps value is multiplied by 1,000. FLAC uses an approximate 60% of raw PCM size; container metadata is not included.
- How do I find the bitrate needed to hit a target file size?
- Use the Bitrate tab: enter your target file size and the duration, and the calculator solves for the average bitrate (in kbps) that fits.
- How do I calculate recording time from available storage?
- Use the Recording Time tab: enter your available storage and the format/quality settings, and the calculator solves for how long you can record.
- Is the bitrate fixed for WAV, AIFF, and FLAC?
- For uncompressed PCM in WAV and AIFF, sample rate × bit depth × channels determines the audio bitrate. FLAC bitrate varies with the audio and encoder settings; this calculator only estimates its size at 60% of raw PCM. MP3, AAC, and OGG estimates use the total bitrate you enter; variable-bitrate encoding may differ.
Selected files are processed locally in the browser and are not uploaded to TrueRes for processing. Open this page in a modern browser to use the interactive tool.