---
title: "Audio file size calculator — Free, No Signup | Murmur"
description: "Estimate audio file size for MP3, AAC, and uncompressed WAV. Calculate MB and MiB from duration, bitrate, sample rate, bit depth, and channels."
canonical: "https://www.murmurtts.com/tools/audio-file-size-calculator"
---
PLAN YOUR EXPORT / FREE TOOL

# Audio file size calculator

Know the size before you export. Compare compressed audio with uncompressed PCM.

## Set your export details.

ESTIMATED AUDIO DATA

9.6 MB

9.16 MiB

128 kbps total · constant or average encoded bitrate

Estimate excludes container headers, artwork, and metadata. Actual compressed sizes vary with encoding.

## How to use this tool

1. Enter the audio duration in minutes.
2. Choose compressed audio and a bitrate, or PCM and its sample settings.
3. Read the estimated size in MB and MiB. Allow a little extra space for metadata.

File size in bytes = duration in seconds × bitrate in bits per second ÷ 8. For uncompressed PCM, bitrate = sample rate × bit depth × channels. A 10-minute recording at 128 kbps is about 9.6 MB before metadata.

YOUR NEXT RECORDING

## Give your script a voice.

Create narration with Murmur, the local voice studio for Apple Silicon Macs.

[Create audio with Murmur](https://www.murmurtts.com/#product)

## Audio file size calculator: questions answered.

How big is a 1-hour MP3 at 128 kbps?

Approximately 57.6 MB, or 54.93 MiB, before metadata and container overhead. Variable bitrate files depend on their actual average bitrate.

Why are MB and MiB different?

One MB is 1,000,000 bytes. One MiB is 1,048,576 bytes. Apps can display the same file size using different units.

How do I calculate WAV file size?

For uncompressed PCM WAV, multiply sample rate, bit depth, channel count, and duration, then divide by eight for bytes. Headers and metadata add a small amount. Compressed WAV uses a different calculation.

Does stereo double an MP3’s size?

Not when the total encoded bitrate stays the same. The compressed bitrate already covers all channels. For uncompressed PCM, doubling the channel count doubles the audio data size.

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