What this Audio File Size Calculator does
The Audio File Size Calculator estimates the storage required for uncompressed pulse-code modulation (PCM) audio. It multiplies the recording duration by the number of samples captured each second, the number of bits used for each sample, and the number of audio channels. It then converts bits to bytes and decimal megabytes.
This estimate is useful during content and media production when planning a recording session, transferring source audio, or organizing project storage. It describes the audio data itself under the selected settings. The calculator's description excludes file headers and metadata, so an actual exported file may be slightly larger. The estimate also does not calculate compressed formats such as MP3, AAC, or Opus, because their sizes depend on encoding choices and audio content.
The calculator uses these inputs:
- Duration in seconds
- Sample rate in hertz, or samples per second
- Bit depth in bits per sample
- Channels, such as mono, stereo, or six-channel 5.1 audio
The result is labeled Estimated Size (MB). It uses decimal megabytes, where one MB is 1,000,000 bytes. Some operating systems display storage using binary units, which can make the same file appear to have a different numerical size.
How to use the Audio File Size Calculator
Choose settings that match the audio you expect to record or export. Enter the duration in seconds. For a three-minute segment, enter 180. Select the sample rate, bit depth, and channel count from the available options. The result updates to show the estimated uncompressed size in MB.
For example, estimate a three-minute stereo recording at 44,100 Hz and 16-bit depth. The duration is 180 seconds, the sample rate is 44,100 samples per second, the bit depth is 16 bits, and stereo uses two channels. Applying the calculator's formula gives:
180 × 44,100 × 16 × 2 ÷ 8 ÷ 1,000,000 = 31.752 MB
Rounded to two decimal places, the estimated size is 31.75 MB. This is a calculation of PCM audio data, not a prediction for a compressed export. If the planned recording uses a different channel layout or technical setting, update that input before using the estimate for storage planning.
How the Audio File Size Calculator formula works
Digital PCM audio represents each sample with a set number of bits. The sample rate determines how many samples are recorded each second. Multiplying the duration in seconds by the sample rate gives the number of samples per channel across the recording. Multiplying by bit depth gives bits, and multiplying by channel count accounts for each recorded channel.
The calculator then divides by eight because one byte contains eight bits. It divides by 1,000,000 to express the byte total in decimal megabytes. Written as an equation, the formula is:
Size in MB = duration × sample rate × bit depth × channels ÷ 8 ÷ 1,000,000
Each part represents a measurable property of the audio. A longer recording has more samples. A higher sample rate captures more samples per second. A higher bit depth stores more bits for each sample. More channels require separate sample data for each channel. With other inputs held constant, raising any one of these values raises the estimated uncompressed size proportionally.
The formula assumes that all selected channels use the same sample rate and bit depth throughout the full duration. It does not model compression, variable bit rates, silence trimming, container overhead, or changes in settings during a project. Those details require information beyond the calculator's four inputs.
Use cases for the Audio File Size Calculator
Production teams can use a rough PCM size estimate to make practical planning decisions before recording or exporting. The figure can help compare format settings and identify when a project may require additional working storage.
- Session planning: Estimate the space for a planned recording length before starting a voiceover, interview, or music session.
- Project storage: Compare the approximate size of mono and stereo source material when organizing a production drive.
- Transfer preparation: Get a baseline estimate before moving uncompressed audio between collaborators or workstations.
- Setting comparisons: See how changing sample rate, bit depth, or channel count affects the PCM data estimate.
- Archiving: Roughly estimate the combined storage for a set of recordings by calculating each duration and adding the results.
For a project with several clips, calculate each clip separately if their settings or durations differ. Add those estimates for a basic total. Keep room for project files, alternate takes, exports, and other production assets because this result covers only the selected audio data.
Other factors to consider when calculating audio size
The file format can change the final storage requirement substantially. A lossless or lossy compressed file does not follow the calculator's uncompressed PCM formula. For compressed audio, the encoder settings, such as target bitrate, and sometimes the material itself affect the result. Use an export estimate from the relevant software or inspect a representative encoded file when you need a compressed-file estimate.
Container formats can also add headers, metadata, markers, and other information. The calculator excludes these elements by design. Their contribution is commonly small relative to long recordings, but the exact amount depends on the format and embedded data. Multitrack sessions may also contain separate files for each track, so account for every recorded track rather than assuming a stereo mix represents the whole project.
Finally, distinguish MB from MiB when comparing estimates with a computer's storage display. Decimal MB equals 1,000,000 bytes, while binary MiB equals 1,048,576 bytes. The byte count can be the same even when the displayed unit value differs. Treat this calculator as a transparent planning estimate for uncompressed PCM data and check the target recording or export settings for the final file size.
Audio File Size Calculator FAQ
Does this calculator estimate MP3 or AAC file sizes?
No. It estimates uncompressed PCM data from duration, sample rate, bit depth, and channel count. Compressed formats need encoder settings such as bitrate, which are not inputs here.
Why does a stereo recording use twice the channel count of mono?
Stereo audio contains two channels, while mono contains one. Under the formula, two channels require twice as many sample bits as one channel when duration, sample rate, and bit depth are the same.
Why can the actual file be larger than the estimate?
The estimate excludes headers and metadata. A file container can include those items, and a production project may also contain additional tracks, markers, or alternate takes that are outside the calculation.
What does the sample rate mean?
Sample rate is the number of audio samples captured per second, measured in hertz. The calculator offers 22,050, 44,100, 48,000, and 96,000 Hz as choices.
Is the result in MB or MiB?
The result is in decimal MB, using 1,000,000 bytes per MB. MiB uses 1,048,576 bytes, so a device that reports binary units may show a different number for the same data.