Use the free Audio File Size Calculator below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
How Big Will That Recording Be?
Nothing ruins a recording session like a full disk, and nothing ruins a website like an audio file ten times larger than it needs to be. File size is not a mystery. It is simple arithmetic: how long the audio is, times how much data each second carries. This calculator does that arithmetic for you, for uncompressed formats like WAV and AIFF, and for compressed formats like MP3, AAC, and OGG, plus a rough estimate for FLAC.
Start with duration, because it is the one factor you always know. A three-minute song, a thirty-minute podcast episode, and a two-hour lecture have wildly different storage needs even at the same quality. Enter minutes and seconds, then pick your format. The tool shows the total size, the size per minute, and the size per hour, so you can scale the answer to any project, from one track to a whole audiobook.
Uncompressed Audio: WAV and AIFF
Uncompressed audio stores every sample as a number, with no clever tricks. The size formula is: duration in seconds, times sample rate in samples per second, times bit depth divided by eight to get bytes, times the number of channels. CD quality is 44,100 samples per second, 16 bits, stereo. Plug in one minute: 60 times 44,100 times 2 times 2 equals 10,584,000 bytes, about 10.1 megabytes. That is why a three-minute CD-quality song is about 30 megabytes as a WAV, and why an hour of it passes 600 megabytes.
Higher settings grow fast. Studio quality at 48,000 samples per second and 24 bits, stereo, uses about 16.4 megabytes per minute. At 96,000 samples and 32 bits, the same minute needs about 46 megabytes. Those settings capture more detail, but ask whether your project needs it. For a podcast voice, CD quality is already generous. For music archiving, higher settings make sense because you keep the master forever and compress copies later.
Compressed Audio: MP3, AAC, and OGG
Compressed formats throw away sounds the human ear barely notices, and store the rest efficiently. Their size formula is simpler: duration times bitrate divided by eight. At 128 kilobits per second, one minute is about 0.96 megabytes. At 320 kilobits per second, the same minute is about 2.4 megabytes. The sound quality difference between those two settings is real on good headphones, but both are far smaller than the 10 megabytes of CD-quality WAV.
Choosing a bitrate is a trade-off, not a moral question. Speech survives happily at 96 or 128 kilobits per second. Music for casual listening sounds fine at 192. Music for careful listening deserves 256 or 320. Audiobooks at 128 sound clean and keep downloads small. The calculator lets you compare instantly: enter your duration once, change the bitrate, and watch the size move. That comparison is worth more than any rule of thumb.
FLAC: The Honest Estimate
FLAC compresses without throwing anything away, which means its size depends on the audio itself. A quiet piano recording compresses more than a loud rock mix. There is no fixed bitrate, so the tool estimates FLAC at about 55 percent of the matching WAV size. Treat that as a planning number, not a promise. Real FLAC files commonly land between 50 and 70 percent of WAV size, depending on the material. If your estimate says 100 megabytes, plan for 110 and you will rarely be surprised.
Planning Real Projects
Use the per-hour figure for podcasts and audiobooks. An hour of spoken word at 128 kilobits per second is about 58 megabytes, so a ten-hour audiobook is about 580 megabytes. Use the per-minute figure for music libraries. A thousand songs at three minutes each, at 256 kilobits per second, need roughly 5.8 gigabytes. Use the uncompressed figures before recording, so you format the right memory card and set the right session length. A 32-gigabyte card holds about three hours of 24-bit studio audio, but about fifty hours of MP3 at 128 kilobits per second.
Frequently Asked Questions
Why is my real file slightly bigger than the estimate? File headers, tags, album art, and encoder padding add a small overhead. The estimate covers audio data, which is nearly all of the file.
Is a bigger file always better quality? No. Beyond a point, extra data captures detail nobody can hear. Match the format to the purpose, and keep a high-quality master for archiving.
What about mono versus stereo? Mono uses half the data of stereo at the same settings. For a single voice, mono is often the smarter choice.
Enter your duration, pick your format, and know your file size before you press record.
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