Audio File Size Calculator - WAV, MP3 & FLAC Estimates

Audio file size follows directly from how many bits per second the format stores. For uncompressed PCM audio — what a standard WAV or AIFF file contains — every second holds one sample per channel for each tick of the sample rate, and every sample occupies the bit depth. So the data rate is sample rate × bit depth × channels, and dividing by 8 converts bits to bytes. CD-quality stereo (44,100 Hz, 16-bit, 2 channels) works out to 1,411,200 bits — 176,400 bytes — every second, or about 10.58 MB per minute. That is why a 3-minute WAV lands at 31.75 MB while the same song as a 320 kbps MP3 is 7.2 MB. Compressed lossy formats such as MP3, AAC, and Ogg Vorbis throw away the sample-rate-times-bit-depth arithmetic entirely: you pick a target bitrate, and the encoder spends that budget on whatever the psychoacoustic model deems audible. Size then depends only on bitrate and duration — kbps × 1,000 ÷ 8 gives bytes per second. A 4-minute track at 320 kbps is 9.60 MB regardless of whether the source was 16-bit or 24-bit. Variable-bitrate (VBR) encodes hover around their average setting, so treat the result as a close estimate rather than an exact figure. Lossless compressors such as FLAC sit in between: they typically shrink PCM to 50-70 percent of the WAV size depending on how complex the music is, so a useful rule of thumb is to compute the WAV size here and take about 60 percent of it. The calculator reports decimal megabytes (1 MB = 1,000,000 bytes), which is what macOS, most cloud-storage quotas, and drive manufacturers use. Windows Explorer historically reports binary mebibytes (1 MiB = 1,048,576 bytes) while labeling them MB, which is why the same file looks about 4.6 percent smaller there — the MiB value shown alongside the result lets you match either display. A few practical notes. Real WAV files add a 44-byte header, and MP3s add ID3 tags plus any embedded cover art, so actual files run slightly larger than the raw math — usually by a few kilobytes unless the artwork is large. Recording at 48 kHz/24-bit, the common film and session standard, costs 17.28 MB per stereo minute, and 96 kHz/32-bit multiplies that quickly: an hour of stereo comes to about 2.76 GB. When planning a recording session, multiply the per-minute figure by track count, not just time — eight mono inputs at 48 kHz/24-bit consume 69.12 MB per minute of takes. For uploads and podcast feeds, working backward is just as useful: a 100 MB limit holds about 69 minutes of 192 kbps audio or 41 minutes at 320 kbps.