Why MP3 to WAV, for this MP3 file
Some editors and hardware want WAV even when the recording started as MP3.
The WAV sound you will actually get
The MP3 is decoded and saved as WAV on your device.
The WAV is larger and it does not sound better than the MP3. Quality lost in the MP3 is gone.
MP3 to WAV without the extra promises
MP3 to WAV sits on this site because MP3 and WAV are not interchangeable, even when they look similar in a file list. Some editors and hardware want WAV even when the recording started as MP3. Podcast hosts, cars, WhatsApp, and old speakers expect MP3. Editors and some hardware want WAV even when the recording started as MP3.
The MP3 is decoded and saved as WAV on your device.
Read this about MP3 before you upload
MP3 is the audio file that plays everywhere. It is lossy. Music is often 192 to 320 kbps. Speech can be lower. Each MP3 save throws away a little more. Turning MP3 into WAV or FLAC does not bring the lost detail back.
Keep WAV or FLAC if you might edit again. Keep the MP3 if it is your only copy.
Read this about WAV before you send the download
The download has to be WAV, because that is the format the next step named. Editors and some hardware want WAV even when the recording started as MP3. A true WAV master is the right archive during an edit.
Do not describe that WAV as a studio master. It cannot sound better than the MP3.
Keep, check, then delete
People lose time when they convert before they know which rule failed. Size, pixel dimensions, codec, font encoding, and layout are different rules. MP3 to WAV only addresses the MP3 to WAV step. Some editors and hardware want WAV even when the recording started as MP3. The MP3 is decoded and saved as WAV on your device. The WAV is larger and it does not sound better than the MP3. Quality lost in the MP3 is gone. The file stays on your device. The first run downloads a converter, so keep this tab open. A phone runs out of memory on long files. A computer is the safer place for a big clip. Do the test with a short or simple file first when the real file is large. A one-page PDF, a single photo, or a one-minute clip will show you whether the output is the kind of file you needed. After that test looks right, run the real file once. Keep both the MP3 original and the WAV download until the receiving person or the upload form accepts it. Audio conversions are one-way once the format is lossy. MP3 to WAV can change the container or the codec so a player opens the file. It cannot make a muffled take clearer, and it cannot turn an MP3 into a studio master by calling the result WAV or FLAC. Finish the edit on the best copy you have, then make the share file once.
Here is the decision for MP3 to WAV. You start with MP3 and you stop when a real program accepts WAV. Compatibility is the reason to make an MP3, not an improvement in sound. A WAV made from MP3 is only a larger box around the same lossy sound. If those two sentences describe a tradeoff you do not want, do not convert. Renaming the extension by hand will not do this job. Running the tool twice on its own output will not do it either.
The WAV is larger and it does not sound better than the MP3. Quality lost in the MP3 is gone.
A related step, if you still need one, is WAV to MP3.
Other jobs start from the homepage, where each tool is named for the conversion it actually does.