Audio Converter Online
Free audio converter in your browser: turn audio or video into MP3, WAV, M4A, FLAC, OGG or OPUS. Trim, normalize and batch convert. Nothing is uploaded.
- Free, no sign-up
- Files stay on your device
- No watermark
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How to convert an audio file
Upload one or many audio files, or videos to extract the sound from.
Pick MP3, M4A, WAV, FLAC, OGG or OPUS and the quality. Trim or normalize if you like.
Listen to the result and download it, or get all files as a ZIP.
A complete audio converter that runs in your browser
Six formats, real estimates
Convert to MP3, M4A (AAC), WAV, FLAC, OGG Vorbis or OPUS. Each format shows the estimated size for your files before you start, and you choose the bitrate, sample rate and mono or stereo.
Extract audio from video
Drop an MP4, MOV, MKV, WEBM or AVI video and get its soundtrack as an audio file. The video is read straight from your disk instead of being copied into memory, so long recordings can be handled.
Trim, normalize and fade
Cut a section with a built-in player, bring quiet recordings up to a standard loudness, add fade in and fade out, or speed up a lecture without changing the pitch.
Private and free, no limits
The converter runs on your device, so files are never uploaded. There is no sign-up, no watermark and no daily limit. Batch convert as many files as your device can handle.
A private audio converter for music, voice and video sound
BestConverter's audio converter runs a full audio engine inside your web browser. Your music, voice memos, podcasts and videos are converted on your own computer or phone and never sent to a server. Add one file or a whole batch, pick a format once, and every file is converted with the same settings. The options window shows the length, codec, sample rate and channels of each file, and an estimate of the size each output format will produce.
Choose the right output format
- MP3 works on every phone, car stereo and app. 192 kbps is a good default; 320 kbps is the maximum.
- M4A (AAC) is the format of Apple Music and iTunes and is well supported on Android.
- WAV is uncompressed audio for editing software, in 16-bit or 24-bit.
- FLAC is lossless: the same sound as WAV in roughly half the size.
- OGG Vorbis and OPUS are open formats. OPUS makes the smallest files and is ideal for speech.
More than a format change
For a single file, a player lets you mark the start and end of the part you want, which is handy for ringtones, interview clips or removing silence at the start of a recording. You can switch voice recordings to mono (this halves a WAV or FLAC file), change the sample rate (for example 16 kHz for speech tools), normalize loudness, add fades of up to 5 seconds and change the playback speed from 0.5x to 2x without changing the pitch. Title, artist and album tags are kept unless you turn them off.
Tips for the best result
Keep the original sample rate unless a device or app asks for a specific one. For a batch of files recorded at different volumes, turn on normalization so they play at the same level. When the source is already MP3 or AAC, converting to the same or a lower bitrate is enough; a higher bitrate only makes the file bigger.
Honest limits
Album cover images are not copied to the new file. Only the first audio track of a video is extracted, and trimming is available when you convert one file at a time. Because everything runs on your device, very large uncompressed results can exceed the memory a browser tab may use; compressed formats or trimming avoid this.
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Frequently asked questions
What audio formats can this audio converter open and create?
It opens MP3, WAV, M4A, AAC, FLAC, OGG, OPUS, WMA, AIFF, AMR and AC3 audio, plus MP4, MOV, MKV, WEBM, AVI, WMV, FLV and 3GP videos. The result can be MP3, M4A (AAC), WAV, FLAC, OGG (Vorbis) or OPUS. Files protected with DRM, such as some purchased music, cannot be converted.
What is the best audio format and bitrate to choose?
MP3 at 192 kbps plays everywhere and sounds transparent for most music. M4A (AAC) is the native format of iPhones and iTunes. OPUS gives the smallest files for the same quality and is excellent for speech at 32-64 kbps. Choose WAV for editing software, and FLAC to keep perfect quality in about half the size of WAV.
How do I extract audio from a video online?
Upload the video, choose an audio format such as MP3 or M4A and press Convert. Only the first audio track is used. If a video has no sound, the converter tells you instead of producing an empty file.
How can I make quiet audio files louder?
Turn on Normalize loudness: it measures how loud the recording sounds (EBU R128) and adjusts it to -16 LUFS, the usual level for podcasts and streaming, while keeping peaks below -1.5 dB. If you prefer a fixed change, turn it off and use the Volume slider from -15 to +15 dB.
Does converting MP3 to WAV or FLAC improve sound quality?
No. Converting a compressed file such as MP3 to WAV or FLAC keeps the quality it already has, without restoring details that were lost. Converting between lossy formats loses a little more each time, so use a high bitrate, or a lossless format, when the source is good.
Is it safe to convert audio files online here?
Yes. Your files are never uploaded. The converter itself (about 31 MB) downloads once when you first use the tool and your browser keeps it in its cache; after that, all the work happens on your device. Very long WAV results can be limited by your browser memory, especially on phones.