Create real MP3, WAV, OGG, M4A and WebM test audio with the exact size and duration you need. Pick a format, set the size and duration, and generate.
Generate test audio files in various formats with natural sounds.
🔧 Size matching: the audio is encoded at the highest bitrate that fits the target size, and padded to the exact size. If even the lowest bitrate is too large, the audio is shortened.
Compatible with all major audio players and browsers
Every format is encoded with its real codec in your browser, so the files pass content-based type checks and work with audio libraries. You can choose the sound: white noise, a sine wave tone, simulated rain, an ambient drone or a synthetic bird chirp.
The advanced options only offer the channel layouts and sample rates each format supports. Bit depth applies to WAV; compressed formats are encoded by bitrate.
Enter a target size up to 2,000 MB and the file comes out at exactly that many bytes (FileMock uses binary megabytes: 1 MB = 1,048,576 bytes).
Compressed formats are encoded at the highest bitrate that fits the target, and the rest of the size is filled with padding that players ignore. In MP3 and OGG files the padding sits inside the file's metadata, so players still show the correct duration. If even the lowest bitrate is too large for the duration you entered, the audio is shortened.
WAV is uncompressed, so its size is fixed by the settings: each second of 44.1 kHz stereo 16-bit audio takes about 0.17 MB. When the duration you entered doesn't fit the target, the audio is shortened; otherwise the remaining space is padded. The generator shows this before you start.
Answers to common questions about generating test audio files.
