Free Audio File Size Calculator: WAV, MP3, FLAC, AAC, and More

File Size in bytes = Sample Rate in Hz times (Bit Depth divided by 8) times Number of Channels times Duration in seconds. For a 3-minute (180-second) stereo WAV at CD quality (44,100 Hz / 16-bit / 2 channels): 44,100 times 2 times 2 times 180 = 31,752,000 bytes = 31.75 MB. This is exact: the raw PCM data in a WAV file is a fixed number of bytes determined entirely by these four parameters. The WAV container header adds only 44 bytes, which is negligible beyond the first few seconds of audio.

For lossy compressed formats (MP3, AAC, OGG, Opus), file size is determined by bitrate and duration only: File Size in bytes = (Bitrate in kbps times 1,000 divided by 8) times Duration in seconds. Sample rate and bit depth determine the quality of the source audio before encoding, but once the bitrate is set, the output file size depends only on the bitrate and how long the audio is. A 128 kbps MP3 and a 128 kbps AAC of the same 60-minute audio will both be approximately 57.6 MB, regardless of whether they were encoded from a CD-quality or hi-res source.

Unlike WAV, which is uncompressed and produces a deterministic file size, FLAC uses lossless compression whose ratio varies with the audio content. Dense, complex orchestral recordings compress less efficiently than simple spoken-word audio or silence. The typical FLAC compression ratio for mixed music content runs from 55% to 65% of the original WAV size, with 60% as a commonly cited average. This calculator uses 60% as the default estimate. Real FLAC files of your specific audio may be somewhat smaller or larger. For archival planning, use the WAV size as your guaranteed upper bound and treat the FLAC estimate as a space-saving projection.

For music intended for streaming and download delivery, 44,100 Hz (CD quality) is the standard and the preferred format for most distribution aggregators including DistroKid, TuneCore, and CD Baby. For projects synced to picture (film, TV, advertising), use 48,000 Hz, which is the SMPTE broadcast audio standard used throughout US television and film production. For archival recording where maximum future-proofing is the goal, the Library of Congress recommends 96,000 Hz / 24-bit WAV. Avoid 192,000 Hz for most work: the storage cost doubles over 96,000 Hz with no audible benefit for material that will be delivered at 44.1 or 48 kHz.

A weekly 45-minute podcast published 52 times per year, delivered as 128 kbps mono MP3, produces approximately 52 times 43.2 MB = 2.25 GB of delivery files per year. If you also keep the original WAV masters at 44.1kHz / 16-bit mono, that adds approximately 52 times 119.0 MB = 6.2 GB of masters. Total annual podcast storage: approximately 8.5 GB. Most podcast hosting plans include enough storage for this: Buzzsprout offers 250 MB monthly (the plan limits how much you upload per month, not total storage of all episodes). Budget approximately 10 to 12 GB of local storage per year for a typical weekly show with WAV masters and MP3 delivery files.

Upload uncompressed WAV or lossless FLAC to all major streaming platforms. Spotify, Apple Music, Amazon Music, Tidal, and every major US platform re-encodes your uploaded audio into their delivery format (Ogg Vorbis for Spotify, AAC for Apple, FLAC for Amazon HD). If you upload a 320 kbps MP3 and they re-encode it to 256 kbps AAC, you get a compressed copy of a compressed copy: double lossy encoding introduces audible artifacts that degrade from the original. The upload size difference between WAV and MP3 is trivial compared to the quality protection of uploading losslessly.

32-bit float is a recording format used by modern field recorders (Zoom F6, Sound Devices MixPre series, Tentacle Track E) that stores audio as floating-point numbers rather than fixed integers. The practical benefit is that 32-bit float cannot clip: even if the input signal peaks well above 0 dBFS, the recorder captures the full level information and you can apply gain correction in post-production without any quality loss. Files are twice the size of 16-bit recordings and 33% larger than 24-bit integer recordings. Use 32-bit float for location sound, field recording, and any situation where you cannot control incoming levels and retakes are not possible. Use 24-bit integer for studio sessions where levels are controlled.

A typical studio album session with 16 simultaneous tracks, recording at 48kHz / 24-bit, for a 40-minute album with 5 takes per song (12 songs): 40 minutes times 5 takes = 200 minutes of total recording time. File size: 48,000 times 3 times 2 times (200 times 60) times 16 = 331.8 GB of raw audio. Add project files, renders, stems, and safety copies and the total session footprint typically runs 1 to 2 TB. Professional studios in Nashville, Los Angeles, and New York typically provision 2 to 4 TB of fast SSD per album project, with secondary NAS backup running simultaneously during the session.

This causes confusion because drive manufacturers and operating systems use different definitions. Hard drives and SSDs are sold and marketed using decimal megabytes (1 MB = 1,000,000 bytes = 10^6). Operating systems (Windows, macOS, Linux) display storage using binary mebibytes (1 MiB = 1,048,576 bytes = 2^20). This means a 1 TB hard drive holds 1,000,000,000,000 bytes, but macOS reports it as approximately 931 GiB. This calculator uses decimal units (MB, GB) matching storage packaging. When an OS shows a file as smaller than this calculator predicts, it is reporting in binary units (MiB, GiB), not because the calculation is wrong. The actual file byte count is the same either way.

The 3-2-1 backup rule is a data protection guideline widely recommended in professional audio production: keep 3 copies of every irreplaceable recording, on 2 different storage media types, with 1 copy stored off-site or in cloud storage. For a 50 GB recording session: drive 1 (working session on studio SSD), drive 2 (immediate local backup on external HDD), copy 3 (cloud backup to services such as Backblaze, Dropbox, or Google Drive). The total storage provisioned is 150 GB (3 times the raw recording), not counting project headroom. Calculate this before every session so your storage budget covers all three copies.

Multi-track mode multiplies the single-track file size (calculated from your sample rate, bit depth, channel count, and duration) by the number of tracks you enter. If you enter 16 tracks with a stereo (2-channel) setting, the calculator treats this as 16 stereo tracks and multiplies by 16. If you are recording 16 mono tracks (as is common in drum recording where each microphone is mono), set channels to 1 before switching to multi-track mode and entering 16 tracks. The result shows the total combined storage for all tracks at a single take length; multiply by your typical number of takes to get your full session storage requirement.

For podcasts that are primarily speech with occasional music beds or transitions, 128 kbps stereo MP3 or AAC is the standard choice and the threshold above which most listeners cannot detect quality differences on typical earbuds or phone speakers. For music-centric podcasts (DJ mixes, music criticism with full song clips, or shows where audio quality is a central value), 192 kbps stereo MP3 is a reasonable premium choice. 320 kbps for podcasts provides minimal audible benefit over 192 kbps in most listening environments and increases file sizes by 67%. The Podcast file size calculator in drive mode can show you the annual storage and CDN bandwidth implications of each bitrate choice at your typical episode length.

File size scales linearly with channel count for uncompressed formats. A mono file (1 channel) is exactly half the size of a stereo file (2 channels) at the same sample rate, bit depth, and duration. A 5.1 surround file (6 channels) is exactly three times the size of the equivalent stereo file. This is why podcasters recording speech typically use mono: a one-hour mono WAV at 44.1kHz / 16-bit is 317.5 MB versus 635 MB for stereo. There is no quality benefit to stereo for a single-microphone speech recording, and switching to mono halves storage and CDN bandwidth requirements for the life of the show.

The Library of Congress Recommended Formats Statement for audio specifies WAV (Broadcast WAVE Format, BWF) at 96,000 Hz / 24-bit as its preferred preservation format for digital audio materials in the American Folklife Center and other collections. The LOC accepts FLAC as an acceptable alternative (since it is losslessly decodable to identical PCM). The LOC Recommended Formats Statement, published and updated at loc.gov/preservation/resources/rfs, also accepts AIFF at these specifications. For long-term archival purposes, 96kHz / 24-bit WAV or FLAC represents the US institutional standard for audio preservation as of 2026. This is the “Studio 96” preset in this calculator.

Yes. The PDF report includes the file size calculation for your selected format, the format comparison table showing all 8 formats at your current settings, the US streaming platform delivery specifications table, and notes on FLAC estimation accuracy and decimal vs binary storage units. The drive capacity table (how many hours per GB at your settings) is shown when you are in Drive Planner mode and included in the PDF. The report is designed to be a complete session planning reference that you can print and bring to a studio or share with a client.

Yes to both. The calculator is completely free with no account required and works in any modern mobile or desktop browser. The format comparison, drive planner, and platform specs table all reflow for small screens. The PDF download and WhatsApp share work on mobile. You can use the Drive Planner tab on your phone at the music store to verify an SD card or external drive has enough capacity for your planned session, or check the file size result before deciding which format to use for a project.