Compress Audio to Reduce File Size

Why would I need to compress audio files?

Audio compression solves storage and bandwidth problems. Your FLAC music collection takes 50GB but your phone only has 32GB total. Your podcast episodes are 100MB each in WAV but listeners don't want to download huge files. Your website's background music is making pages load slowly. Maybe you recorded interviews at 96kHz/24-bit (overkill for voice) and need to compress them to reasonable sizes, or you're uploading to platforms with file size limits.

Different scenarios need different compression levels. Podcasts can be heavily compressed (64-96kbps) because voice doesn't need high fidelity. Music should be compressed moderately (192-256kbps) to maintain quality. Audiobooks can be mono at 64kbps (half the size of stereo with no quality loss for speech). Compressing audio lets you fit more songs on devices, reduce mobile data usage, speed up website loading, meet platform upload limits, and save cloud storage costs.

How does audio compression work?

Our compressor uses a simple, secure process:

Upload Your Audio

Drag and drop your audio files or click to browse. Your files are encrypted during upload using SSL. We support files up to 100MB (that's several hours of audio).

Choose Quality Settings

Select compression preset (Fast, Normal, Maximum, Ultra) or customize bitrate, sample rate, and channel settings. Our interface shows file size estimates based on your settings.

Server Processing

Your audio is compressed on our servers using FFmpeg, the industry-standard tool used by Spotify, YouTube, and professional studios. Fast, high-quality compression without draining your device's battery or CPU.

Download & Cleanup

Download your compressed audio. We automatically delete all files from our servers within 1 hour for your privacy. No files are stored permanently – we only keep them long enough for you to download.

The entire process typically takes seconds to a few minutes, depending on file size and compression settings. Your original audio is never modified.

What compression settings should I use?

The right settings depend on your use case:

Use 192kbps for general music

192kbps MP3 or 128kbps AAC offers excellent quality that 95% of people can't distinguish from lossless on consumer equipment. Perfect balance between quality and file size. A 5MB song becomes 3-4MB at 192kbps with barely noticeable quality difference.

Use 96kbps for podcasts

Speech doesn't need high bitrates. 96kbps MP3 or 64kbps AAC in mono sounds perfectly clear for voice and reduces file sizes dramatically. A 60-minute podcast drops from 60MB to 7-8MB with no loss in speech intelligibility.

Use 256-320kbps for high-quality music

If you have good headphones or speakers and care about quality, use 256kbps AAC or 320kbps MP3. Near-transparent quality on high-end equipment. Files are larger but still much smaller than lossless (8-10MB vs 30-40MB per song).

Use 44.1kHz sample rate for music

CD quality sample rate (44100 Hz) is perfect for music. Higher rates (48kHz, 96kHz) don't improve perceived quality for most content and just waste space. Use 48kHz only for professional video workflows that require it.

Use mono for speech-only content

Podcasts, audiobooks, and voice recordings don't benefit from stereo. Converting to mono cuts file size in half with zero quality loss for voice. A 20MB stereo podcast becomes 10MB mono with identical speech clarity.

Enable VBR for better efficiency

Variable Bitrate (VBR) adjusts compression dynamically – complex passages get more bits, simple parts get fewer. Results in 10-20% smaller files than constant bitrate with same perceived quality. Perfect for music with varying complexity.

Quick preset guide

Fast = 96kbps (podcasts, voice), Normal = 192kbps (general music), Maximum = 256kbps (high-quality music), Ultra = 320kbps (audiophile music). Use Fast for speech, Normal for everything else unless you have specific quality needs.

Remember: You can always test different settings to see which works best for your needs. The compressor makes it easy to compare results.

Will compression reduce audio quality?

Yes, lossy compression (MP3, AAC, OGG, OPUS) permanently removes audio data to make files smaller. The key is that it removes data humans typically can't hear – very high frequencies above 16-20kHz, quiet sounds masked by louder ones, and subtle details in complex passages. At good bitrates (192kbps+), most people can't distinguish compressed from lossless on consumer equipment. At lower bitrates (96kbps), you'll hear compression artifacts in music but speech still sounds fine.

How much quality loss depends on bitrate. 320kbps MP3 is nearly transparent (indistinguishable from original for 99% of listeners on 99% of equipment). 192kbps is excellent quality where most people stop hearing differences. 128kbps is acceptable for casual listening. 96kbps is fine for podcasts but poor for music. 64kbps is okay for speech-only content but terrible for anything else. The quality trade-off: 320kbps = 10MB song, 192kbps = 6MB song, 128kbps = 4MB song, 96kbps = 3MB song.

Choosing quality levels: Use high bitrates (256-320kbps) for music you'll play on good equipment (studio monitors, audiophile headphones). Use medium bitrates (192kbps) for everyday music listening (Bluetooth speakers, regular headphones, car stereos). Use low bitrates (96kbps) only for speech content where file size matters more than fidelity. Test different settings – compression quality is subjective and depends on your ears and equipment.

Can I compress multiple audio files at once?

Yes! Select multiple audio files at once (hold Ctrl or Cmd while clicking, or drag multiple files into the upload area). All files will be compressed using the same settings you choose. This is perfect for compressing an entire music album, podcast series, or voice recording collection. Compress 10 songs or 100 – the compressor handles them all with consistent quality.

After compression, you can download each file individually, or use the 'Download All as ZIP' button to get all compressed files in one archive. The ZIP option is super convenient when you've compressed a whole album or podcast series – instead of clicking download 15 times, you get one file that extracts into all your compressed audio with proper filenames.

There's no practical limit on batch size. Audio compression is fast – a typical 3-minute MP3 song compresses in 5-15 seconds. Even compressing 50 songs takes just a few minutes. For huge batches (500+ files), consider doing them in groups of 100 to make management easier. The compressor shows progress for each file so you know what's happening.

What bitrate should I use for MP3 or AAC?

Bitrate is like image resolution – higher = better quality + bigger files. For MP3: 96kbps is acceptable for podcasts and spoken word (sounds thin but intelligible). 128kbps is the old standard (okay for casual listening but you'll notice compression artifacts). 192kbps is the sweet spot for most music (good quality, reasonable size). 256kbps is very high quality (hard to tell from lossless for most people). 320kbps is maximum MP3 quality (near-transparent, but files are large). For AAC: You get equivalent quality at 20-30% lower bitrate, so 256kbps AAC ≈ 320kbps MP3.

Practical recommendations: Podcasts/audiobooks: Use 96kbps MP3 (mono saves even more space) or 64kbps AAC. Music for everyday listening: Use 192kbps MP3 or 128kbps AAC. High-quality music: Use 256-320kbps MP3 or 256kbps AAC. Streaming over mobile data: Use 128kbps to save bandwidth. Archival copies: Don't use lossy at all – use FLAC or WAV to keep perfect quality.

Honest truth: Most people can't hear the difference between 192kbps and 320kbps MP3 on consumer equipment (laptop speakers, Bluetooth earbuds, car stereos). The difference only becomes noticeable on high-end headphones or studio monitors. 192kbps MP3 is the practical sweet spot – good enough for 95% of listening situations while keeping file sizes reasonable. Use 320kbps only if you have lossless sources and really care about the last 1% of quality.

Should I compress lossless FLAC files?

It depends on your needs. FLAC is already compressed (losslessly) – it's 40-60% smaller than WAV while keeping perfect quality. Compressing FLAC to MP3/AAC makes files even smaller (5-10x reduction) but permanently loses quality. Do this if you need portable copies for devices with limited storage, want faster streaming over mobile data, or are making distribution copies for platforms with file size limits. Always keep your original FLAC files as master archives.

Best practices: Keep FLAC as your master library backup on your computer or NAS. Compress FLAC to 256kbps MP3 or 256kbps AAC for portable copies on phones and portable players – excellent quality that 95% of people can't distinguish from lossless on consumer equipment. Never delete your FLACs after compressing – storage is cheap and you might want different compression settings later (re-compressing MP3→AAC loses more quality than FLAC→AAC).

For Apple users: Compress FLAC to 256kbps AAC for iTunes and iOS devices. AAC at 256kbps sounds excellent on iPhones and AirPods and is what Apple Music uses for streaming. If you must keep perfect quality and use Apple devices, convert FLAC to ALAC (Apple Lossless) instead of compressing – files stay large but quality is preserved and it works natively in iTunes.

How do I avoid losing too much quality during compression?

Follow these tips to maintain acceptable quality:

Don't compress repeatedly

Each lossy compression loses more quality. Avoid MP3 → AAC → OGG chains. Always compress from your best source (FLAC, WAV, or high-bitrate original) directly to your target format. Never re-compress already compressed files unless absolutely necessary.

Keep lossless masters

Store your music library in FLAC or WAV as master copies. Create compressed copies (MP3, AAC) from these masters whenever needed. You can always make new compressed copies with different settings, but you can never recover quality lost from compressed files.

Don't upsample bitrates

Compressing 128kbps MP3 to 320kbps MP3 doesn't improve quality – it just makes files bigger with the same quality. You can't add detail that isn't there. Always use source file quality as your baseline and compress from there.

Use appropriate bitrates

Match bitrate to content and playback equipment. Music on good headphones deserves 256-320kbps. Music on Bluetooth speakers sounds fine at 192kbps. Podcasts need only 96kbps. Voice recordings work at 64kbps mono. Don't use 320kbps for everything – it wastes space without audible benefit in many cases.

Know when quality matters

High-end headphones reveal differences between 192kbps and 320kbps. Bluetooth speakers and laptop speakers don't. Match your compression level to your listening equipment. If you mostly use AirPods and a car stereo, 192kbps is plenty.

Summary: Keep lossless masters, compress directly from them to final format, use appropriate bitrates for your use case, and avoid re-compressing already compressed files. Quality compression is about finding the right balance between file size and acceptable audio fidelity.

Is this really free? What's the catch?

Yes, completely free – no catch, no hidden fees, no premium tiers, no subscriptions. You can compress unlimited audio files with no watermarks added. We support ourselves through optional donations and non-intrusive ads (which you can block if you prefer). We built this because we were frustrated with other compressors that limit file sizes, add watermarks, or constantly push premium upgrades.

The only real limitations: File size limit of 100MB per audio file (that's several hours of audio), and compression happens on our servers so you need an internet connection. If you need to compress massive files or want offline compression, you'd need desktop software like Audacity or ffmpeg. But for 99% of people compressing everyday audio, our free service works perfectly.

Use your compressed audio however you want – personal projects, podcasts, YouTube, commercial music production, client work, whatever. No attribution required, no restrictions. The audio files are 100% yours. We delete them from our servers within an hour, so they're truly yours with no strings attached.

What audio formats do you support for compression?

We support 55+ audio formats organized by category:

Common formats (7):

MP3, WAV, OGG, AAC, FLAC, M4A, WMA – These cover 95% of what most people need for music, podcasts, and general audio.

Lossless formats (5):

ALAC, APE, WV, TTA, AIFF – Perfect quality preservation for archival, mastering, and professional audio work.

Modern formats (3):

OPUS, WEBM, MKA – Next-generation codecs optimized for streaming and web applications with better efficiency than MP3.

Legacy formats (6):

MP2, AC3, AMR, AU, MID, RA – Older formats for backwards compatibility with vintage equipment and software.

Specialized formats (5):

DTS, CAF, VOC, SPX, DSS – Professional and specialized formats for specific industries like cinema, dictation, and gaming.

Portable/Netpbm Encodings (5):

PPM, PBM, PGM, PNM, PAM – Simple text-based encodings for cross-platform compatibility.

Legacy Encodings (7):

PCX, PICT, PCT, PCD, PDB, PALM, CUR – Older encodings for backwards compatibility with legacy systems.

Specialized Encodings (8):

VIPS, VIFF, MNG, MTV, WBMP, PGX, PAL, MAP – Technical encodings for specific industries and applications.

Fax & Print Encodings (5):

FAX, G3, G4, JBG, JBIG – Monochrome compression encodings for fax machines and document scanning.

Retro Encodings (6):

SIXEL, SIX, HRZ, IPL, PICON, OTB – Vintage computer graphics encodings from 1970s-1990s systems.

How long does audio compression take?

It depends on file size, format, and compression settings. As a rough guide: A 3-minute song typically takes 5-20 seconds. A 60-minute podcast takes 30-90 seconds. Simple compression (lowering bitrate only) is faster than complex operations (changing sample rate, converting formats, normalization). Larger files and aggressive compression take proportionally longer.

Compression speed factors: Lower bitrate compression is faster than higher bitrate. Mono conversion is faster than stereo processing. VBR (variable bitrate) takes slightly longer than CBR (constant bitrate) but produces better results. Batch compression processes files one at a time, so 10 songs take about 10x longer than one song. You'll see a progress bar showing estimated time remaining for each file.

If compression is taking forever: Check your internet connection (slow uploads make it seem stuck). Try lower quality settings for faster processing. Make sure your audio file isn't corrupted (try playing it first). For huge files (100MB+ lossless), just be patient – they genuinely take a few minutes even on fast servers. Most everyday compressions finish in under a minute.

Can I use this on my phone or tablet?

Yes! Our compressor works on iPhones, iPads, Android phones, and tablets. The interface adapts to touch screens and smaller displays. However, there are practical considerations: Mobile browsers have file size restrictions. Uploading large files over cellular data uses a lot of data and takes time. Your phone might time out or go to sleep during long compressions (though most finish in under a minute).

Best practices for mobile: Use WiFi, not cellular data (audio files are large and uploads use significant data). Keep your screen on during compression. Compress shorter audio files (under 10 minutes works best). For compressing entire music albums or large collections, use a computer. Mobile is perfect for quick single-file compressions like podcast episodes or voice recordings.

If you're having trouble on mobile: Try using your computer instead. Make sure you have a stable WiFi connection. Close other apps to free up memory. Update your browser to the latest version. Some older phones struggle with large file uploads – if upload fails repeatedly, the file might be too large for your device.

What happens to my audio metadata and tags?

Metadata (ID3 tags in MP3, Vorbis comments in OGG/FLAC) includes artist, album, title, genre, track number, album artwork, lyrics, and more. Our compressor attempts to preserve basic metadata during compression. Most common tags (artist, album, title, artwork) are usually preserved. The catch: Compression can sometimes strip advanced metadata, and different formats support different metadata fields.

What typically gets preserved: Song title, artist name, album name, track numbers, basic genre tags, and album artwork (if not too large). What might get lost: Advanced tags like lyrics, ReplayGain data, custom fields, multiple artists, detailed credits, and ratings. Metadata preservation depends on source format, target format, and compression settings.

Best practices for metadata: Always keep your original files with complete metadata as masters. Use our compressor for creating distribution copies. For serious metadata management (editing tags, adding artwork, organizing libraries), use dedicated tools like Mp3tag (Windows), Kid3 (cross-platform), or MusicBrainz Picard before compressing. These tools give you full control over tags and work better than trying to preserve tags through compression.

Can I extract and compress audio from videos?

Our compressor focuses on audio-to-audio compression. For extracting audio from video files (getting MP3 from MP4, WAV from MKV, etc.) and then compressing it, you'll need a video converter or audio extraction tool first. We have a separate Video Converter that can help extract audio. Audio extraction from video is a different workflow that requires handling video codecs, containers, and sometimes multiple audio tracks.

Why we don't mix audio and video compression here: They're different tools for different jobs. Audio extraction needs to decode video containers, handle video codecs, select audio tracks (movies often have multiple languages), and deal with sync issues. It's better handled by tools designed specifically for video. Keeping audio compression separate makes it faster, simpler, and more focused on what it does best.

Workaround for extracting and compressing audio from video: Use our Video Converter or desktop software like VLC (Media > Convert/Save) to extract audio first, then use our Audio Compressor to optimize the extracted audio. This two-step approach gives you more control over both extraction quality and compression settings than trying to do everything in one tool.

Should I use OPUS or MP3 for my podcast?

OPUS is technically superior – it sounds better than MP3 at half the file size. A podcast at 64kbps OPUS sounds as good as 96-128kbps MP3, saving bandwidth and storage. OPUS at 96kbps rivals MP3 at 192kbps for music. If you're hosting your podcast on your own website or a modern platform that supports OPUS, and your audience uses modern devices (anything from the last 5 years), OPUS is the better choice. Smaller file sizes mean faster downloads, lower hosting costs, and less mobile data usage for listeners.

But MP3 is universally compatible. It works on everything – old MP3 players, car stereos from 2005, vintage iPods, weird proprietary podcast apps, and every computer made since 1995. If your audience includes people with older devices, or you're distributing through platforms that don't support OPUS yet, MP3 is the safer choice. Use 96kbps for speech-heavy podcasts (perfectly clear voice, tiny files), 128kbps for podcasts with music intros/outros, or 192kbps if music is a big part of your content.

Practical recommendation: Compress to MP3 at 96-128kbps for maximum compatibility unless you have a specific reason to use OPUS. Most podcast platforms (Apple Podcasts, Spotify, Google Podcasts) work best with MP3. Save OPUS for web-only distribution where you control the player and know it supports modern formats. For audiobooks, use mono MP3 at 64-96kbps – voice doesn't need stereo and mono saves 50% space with zero quality loss for speech.