Audio Bitrate Changer Change the bitrate of audio files to adjust quality and file size.

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Audio Bitrate Changer

Change the bitrate of audio files to adjust quality and file size.

Upload Audio

Drop your audio file or click to browse.

Select Bitrate

Choose your target bitrate (64-320 kbps).

Download

Download the re-encoded audio at your chosen bitrate.

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What Is Audio Bitrate Changer?

The Audio Bitrate Changer lets you re-encode audio files at a different bitrate to control the balance between quality and file size. Higher bitrates mean better quality but larger files, while lower bitrates produce smaller files with some quality reduction. Choose from standard bitrate options (64, 96, 128, 160, 192, 256, 320 kbps) and download the re-encoded file. The tool uses the Web Audio API to decode the source and MediaRecorder to re-encode at the target quality level. All processing is browser-based.

Why Use Audio Bitrate Changer?

Control the quality vs. file size tradeoff precisely
Standard bitrate options from 64 to 320 kbps
Preview estimated file size before conversion
All processing in your browser — files stay private

Common Use Cases

File Size Reduction

Reduce large audio files for email attachments or limited storage.

Streaming Optimization

Encode audio at optimal bitrates for web streaming.

Quality Control

Ensure audio meets specific bitrate requirements for platforms.

Bandwidth Saving

Create low-bitrate versions of audio for mobile data conservation.

Technical Guide

The tool decodes the source file into a PCM AudioBuffer using AudioContext.decodeAudioData(). An OfflineAudioContext is created and the decoded audio is rendered through it. The output is captured via a MediaStream and re-encoded using MediaRecorder with the specified bitrate parameter in the constructor options: { audioBitsPerSecond: targetBitrate }. The MediaRecorder uses the browser's native audio encoder (typically Opus in WebM or AAC in MP4) to produce the output at the target bitrate. The estimated output file size is calculated as: duration (seconds) * bitrate (bits/second) / 8 + overhead. The tool supports common bitrate values and displays the quality-size tradeoff for informed decision-making.

Tips & Best Practices

1
128 kbps is the standard for good quality with reasonable file size
2
64-96 kbps is sufficient for voice and spoken word content
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256-320 kbps is near-transparent quality for music
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Increasing bitrate of a low-quality source won't improve its quality

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Frequently Asked Questions

Q What bitrate should I use?

128 kbps is good for general use, 192-256 kbps for music, and 64-96 kbps for voice. Choose based on your quality needs and file size constraints.

Q Does increasing bitrate improve quality?

No. You can't add quality that wasn't in the original. Increasing bitrate only makes the file larger without improvement.

Q What's the relationship between bitrate and file size?

File size (MB) ≈ bitrate (kbps) × duration (seconds) / 8000. So 128 kbps × 240s (4 min) ≈ 3.8 MB.

Q What format is the output?

The output format depends on browser capabilities — typically WebM/Opus or MP4/AAC.

Q Is processing done locally?

Yes. All bitrate encoding happens in your browser. No files are uploaded.

About This Tool

Audio Bitrate Changer is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.