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How to convert WMA to MP3 online
The SimpleSize audio converter accepts WMA files and has MP3 selected as the output by default. You do not need an account.
- Drop the WMA file. Drag it onto the dropzone or click to browse. The converter takes one file at a time.
- Check the two menus. Output format is already MP3. Quality is already Good (192 kbps), which suits most WMA files. The other options are Economy (64 kbps), Standard (128 kbps) and Best (320 kbps).
- Click Convert Audio and download. A progress bar shows the time remaining and you can cancel while it runs. When it finishes, the page shows a download button and the size of the new MP3.
That is the whole job for most files. The rest of this guide covers the two things that go wrong: picking a bitrate that costs quality or wastes space, and files that refuse to convert at all.
Why convert a Windows Media Audio file to MP3?
WMA is Microsoft's audio format. It was the default when you ripped a CD in Windows Media Player, so many music collections from the 2000s are full of .wma files.
The sound is fine. The problem is support. Windows plays WMA out of the box, but iPhones, Macs and many apps, web players and smart speakers do not. MP3 plays on practically everything made in the last 25 years.
So turning a Windows Media Audio file into MP3 is about compatibility, not about improving the sound. That matters for the next section, because the conversion can only keep or lose quality. It can never add any. If the difference between a container and a codec is new to you, what is a codec explains it.
Does converting WMA to MP3 lose quality?
Yes, a little. Standard WMA is a lossy format: when the file was made, the encoder discarded the parts of the sound it judged you would not hear. MP3 does the same thing, but with its own rules about what to discard.
A converter cannot translate one into the other directly. It decodes the WMA to plain audio and then encodes that audio as MP3. The MP3 encoder treats the leftovers of the first encode as real sound and trims again. Audio people call this transcoding, and the extra damage is called generation loss.
How audible it is depends almost entirely on the bitrate you give the second encode:
- Too low and the MP3 encoder has to cut into audio that was already cut once. You hear swishy cymbals, dull highs and a watery stereo image.
- About one step above the source and the MP3 has enough room to store what the WMA still holds. Most people cannot tell the two apart.
- Far above the source and nothing improves. The detail the WMA dropped is gone, so the extra bits store nothing useful.
Keep the original WMA
Do not delete the WMA after converting. If you need another format later, convert from the WMA again. Converting the MP3 would add a third round of loss.
Which MP3 bitrate should you choose for a WMA file?
Match the Quality menu to the bitrate of the WMA you are starting from, then go one step up.
WMA at 64 kbps or lower
Standard (128 kbps)
Typical for voice recordings and old portable players. 128 kbps holds everything such a file contains.
WMA at 96 to 128 kbps
Good (192 kbps)
The most common case for ripped CDs. This is the converter's default.
WMA at 160 kbps or higher
Best (320 kbps)
Gives the second encode the most headroom. Use it for music you care about.
WMA Lossless
Best (320 kbps) or FLAC
Nothing was discarded yet, so this is a first lossy encode, not a second one.
Expect the MP3 to be bigger than the WMA when you step up. At 192 kbps an MP3 takes about 1.4 MB per minute, so a four-minute song lands near 5.8 MB. The same song as a 128 kbps WMA is under 4 MB. That extra space is the price of not losing more quality. The maths behind these numbers is in our guide to audio file size.
How to check the bitrate of a WMA file
On Windows, right-click the file, choose Properties and open the Details tab. The Bit rate line under Audio shows the number you need.
If you cannot check, keep Good (192 kbps). It is safe for almost any WMA ripped from a CD.
What to do with WMA Lossless files
Windows Media Player could also rip to WMA Lossless. Those files are large, often well above 700 kbps in the Details tab, and they hold the full CD audio.
If you only need the song on your phone, an MP3 at Best (320 kbps) is fine. If you want to keep a perfect copy in a format more players understand, set Output format to FLAC instead. FLAC is lossless too, so no Quality menu appears for it.
Why does a WMA file fail to convert?
The usual reason is copy protection. Older versions of Windows Media Player had a "Copy protect music" option for ripping CDs, and music stores of that era sold WMA tracks locked with Microsoft's DRM. A protected file is encrypted and tied to a licence on the computer that created it.
No ordinary converter can read that audio, ours included. If you upload a protected file, the converter stops with a message that it could not convert the audio.
How to tell if a WMA file is protected
Open Properties and the Details tab again and scroll to the bottom. A line named Protected says Yes or No.
If it says Yes, you have two honest options:
- You still have the CD: rip it again with copy protection switched off, or rip it straight to MP3.
- You bought the track online: check whether the store or its successor lets you download it again without DRM.
If the file is not protected and still fails, it may be damaged or incomplete. Try playing it to the end in Windows first.
Online converter WMA to MP3: limits and privacy
Here is what the SimpleSize converter does and where it stops, so there are no surprises halfway through an album.
| Question | Answer |
|---|---|
| Maximum file size | 100 MB per file |
| Files per run | One at a time |
| Daily limit | 10 conversions a day, shown under the dropzone |
| MP3 bitrates | 64, 128, 192 or 320 kbps |
| Other outputs | WAV, M4A, AAC, FLAC, OGG, WMA, AIFF, MP2 |
| Where it runs | On our server. The file is deleted 30 minutes after the result is ready |
| Account | Not needed |
100 MB is a lot of WMA. At 128 kbps it is roughly 100 minutes of audio, so single songs, full albums ripped as one file and most lectures fit.
A failed conversion does not use up one of your 10 daily runs. Only finished ones count.
The daily limit is the thing to plan around. For a few albums, convert the tracks you want over a couple of days. For a whole library of hundreds of files, a local tool is the better fit.
Can you convert WMA to MP3 with FFmpeg?
Yes. FFmpeg is a free command-line tool, and it is what our converter runs on the server, with the LAME MP3 encoder. On your own computer it has no file or daily limits. This command does the same job as the Good (192 kbps) setting:
ffmpeg -i song.wma -c:a libmp3lame -b:a 192k song.mp3To convert every WMA in a folder on Windows, open Command Prompt in that folder and run:
for %f in (*.wma) do ffmpeg -i "%f" -c:a libmp3lame -b:a 192k "%~nf.mp3"Change 192k to 128k or 320k using the same rule as above. The FFmpeg codec documentation lists the other MP3 encoder options, and the LAME project documents the encoder itself. For background on the WMA family, including the Pro and Lossless variants, see Windows Media Audio on Wikipedia.
FFmpeg cannot open protected files either. DRM stops every tool at the same point.
Frequently asked questions about WMA to MP3
Not in a way that helps here. At the same bitrate the two sound broadly similar, and a converted MP3 can never sound better than the WMA it came from. You convert for compatibility, not for quality.
No. It will sound at best the same as the WMA, in a file more than twice the size. For a 128 kbps source, Good (192 kbps) keeps what is there without wasting space.
Because file size follows bitrate, and you chose a higher one. A 192 kbps MP3 is about 1.5 times the size of a 128 kbps WMA of the same song. That is expected when you step up to protect quality.
The SimpleSize audio converter handles one file per run, up to 10 runs a day. For a large folder, the FFmpeg loop in this guide converts every WMA in one go on your own computer.
Not with a converter. The audio is encrypted, so the conversion fails. Re-rip the CD with copy protection turned off, or download the track again from the store if it now offers a version without DRM.
Turn your WMA file into an MP3
Drop the file, keep MP3 and Good (192 kbps), and download. Files up to 100 MB, no signup.