WMA Compressor

How to Compress WMA Files Online

1. Upload Your WMA Files: Drag and drop or click "+ Add Files" to load WMA audio from your device. Batch upload is supported — process a whole legacy library, audiobook set, or sermon archive in one pass. Files stay in your browser session.
2. Pick a Compression Method: Choose File Size Percentage (default 80% — a 10 MB file targets ~8 MB), Specific file size to enter an exact KB or MB target, Custom Bitrate in bps/Kbps/Mbps, Constant Bitrate presets from 8 kbps to 384 kbps (64 kbps default), or Variable Bitrate ranges scoped to WMA v1/v2 (e.g., 48k–64k, 96k–128k, 160k–192k).
3. Tune Audio Settings (Optional): Switch Audio Channel between Mono and Stereo (mono roughly halves voice-file size), set Audio Sample Rate to 8000, 16000, 24000, 44100, or 48000 Hz, or change Audio Codec between WMA v2 (default, broadest playback) and WMA v1 (older device support).
4. Trim and Compress (Optional + Final): Use Trim to set a start time and duration in seconds or HH:MM:SS.sss, then click Compress. Download each file individually or as a ZIP. No sign-up, no watermark, no email gating.

Why Compress WMA Files?

WMA (Windows Media Audio) launched on August 17, 1999 as Microsoft's MP3 competitor inside Windows Media Technologies 4.0, and it remains common in legacy Windows libraries, ripped CD archives, voice recorders, and older portable players. High-bitrate WMA files (192–320 kbps) waste storage for spoken-word content, podcasts, voice memos, and casual music playback. Re-encoding to 64–128 kbps typically cuts file size 50–75% with minimal audible loss for the intended use case.

• Legacy Windows libraries — Shrink a Windows Media Player rip collection in place without converting away from WMA, preserving device compatibility for Zune-era players, older Garmin/Sony car stereos, and Windows-only home audio receivers.
• Voice recorders and dictation — Olympus, Sony, and Philips voice recorders often save at 64–128 kbps stereo when the content is mono speech; downmixing to mono and dropping to 32–48 kbps cuts size by 70%+ without intelligibility loss.
• Audiobooks and sermons — A 2-hour 128 kbps stereo WMA sermon is roughly 110 MB; re-encoded to 48 kbps mono it lands near 40 MB, fitting easily under chat and email caps.
• Email and chat attachments — Personal Gmail caps attachments at 25 MB, Outlook.com at 20 MB, and Discord's free tier dropped to 10 MB per file in September 2024; a Specific file size target lets you hit any of those exactly.
• Cloud-storage cost — Halving the bitrate of a 50 GB WMA archive on OneDrive or Google Drive saves roughly 25 GB, directly reducing paid-tier spend.
• Older portable devices — Pre-2010 MP3 players, in-car CD/USB head units, and PMP devices that support WMA but have 1–8 GB of flash storage hold far more content at 96–128 kbps than at 256–320 kbps.

If you'd rather move to a modern codec entirely, see WMA to MP3, WMA to AAC, or WMA to Opus. For pure trimming without re-encoding, use Trim WMA or Audio Cutter.

WMA Bitrate Cheat Sheet — Which to Pick

Numbers assume stereo at 44.1 kHz unless noted; "size per hour" is the resulting file for one hour of audio at that bitrate. WMA Standard (v2) supports up to 48 kHz with stereo channels.

WMA vs MP3 vs AAC vs Opus — Format Comparison

Frequently Asked Questions

Is WMA still worth using in 2026, or should I convert to another format?

WMA Standard is a legacy codec — Microsoft hasn't released a new version since WMA 10 in 2003, and modern Windows defaults to AAC or MP3 for new recordings. If you have an existing WMA library that already plays on every device you use, compressing in place is the path of least friction. If you're starting fresh or need iOS/Android/Mac playback without re-encoding, WMA to AAC or WMA to Opus gives you better quality per MB and far broader native support.

What bitrate should I pick for WMA compression?

For voice content (podcasts, audiobooks, sermons, lectures) 48–64 kbps mono is more than enough; intelligibility doesn't improve above that. For music you actually listen to, 128 kbps stereo is a reasonable floor and 192 kbps is close to transparent on most equipment. Going above 256 kbps in WMA Standard rarely produces audible improvement — at that point a lossless format (FLAC, ALAC, WMA Lossless) is the better archival choice.

What's the difference between WMA v1 and WMA v2 in the codec dropdown?

WMA v2 (default) is the version that shipped from Windows Media 7 onward (2000) and is what nearly all modern WMA decoders expect. WMA v1 is the original 1999 encoder; it exists for compatibility with a handful of very old playback chains (early portable players, certain car head units from 2000–2004) that don't recognize v2 streams. Pick v2 unless a specific device refuses to play your file.

Does VBR or CBR sound better for WMA?

Variable Bitrate (VBR) allocates more data to complex passages and less to silence, so for music it produces better quality per MB than Constant Bitrate (CBR) at the same average. CBR is more predictable for streaming, fixed-size file caps, and older decoders that mis-handle VBR seeking. For modern playback and archival re-encodes, VBR is the better default; for "I need this file under exactly 8 MB" use CBR with the Specific file size option.

Will compressing change the metadata (title, artist, album art) on my WMA?

No. Title, artist, album, track number, year, genre, and embedded album art live in the WMA file's ASF header, not in the audio stream. Re-encoding rewrites the compressed audio but copies the existing metadata through unchanged.

Will my compressed WMA still play in Windows Media Player and on my Sonos / older car stereo?

WMA Standard v2 at any sample rate from 8 kHz to 48 kHz plays in Windows Media Player on Windows 7 through Windows 11, in VLC on every platform, on Sonos systems, and on essentially any device that ever advertised "WMA support." Sticking with v2 (the default) and using a sample rate of 44.1 or 48 kHz is the safest combination. If a device fails, drop to 22.05 kHz mono — that's the lowest-common-denominator that pre-2005 hardware also recognizes.

Can I hit a specific file size, like "exactly 10 MB for Discord"?

Yes — pick Specific file size, enter your target in MB, and the encoder back-calculates the right bitrate from the file's duration. Useful for Discord's 10 MB free-tier cap, Outlook.com's 20 MB attachment ceiling, Gmail's 25 MB limit, or any other hard cap. Aim a touch under your target (e.g., 9.5 MB for a 10 MB cap) to leave headroom for the ASF container overhead and metadata.

Does trimming before compression help reduce size further?

Yes — trimming removes audio outside your selected start/duration window before the encoder runs, so the size drop is proportional to the removed time. Cutting 10 minutes of silence or intro music off a 60-minute file saves ~17% on its own; combine that with a bitrate drop and a stereo-to-mono switch and you can routinely hit 80%+ total size reduction on voice content.

Why is my WMA Lossless file so much bigger than other WMA files I have?

WMA Lossless is a different codec from WMA Standard — it preserves the source audio bit-for-bit and typically sits at 400–900 kbps, which is 3–7x the size of a 128 kbps WMA Standard file. The compressor here re-encodes to WMA Standard (v1 or v2), which is lossy. If you want to keep lossless quality, convert to FLAC instead; if you want a small playable copy from a Lossless source, expect a dramatic size drop because you're moving from lossless to lossy.