Use this FLAC to AAC converter when an application or recipient asks for a standalone .aac audio file. Upload one FLAC, start conversion, and download the AAC when it finishes. The tool is free, with no account or software installation required.
The output is lossy AAC-LC audio in ADTS format. It is not lossless audio and is not an M4A file. Keep the original FLAC if you need exact preservation or a source for future edits.
What changes when FLAC becomes AAC?
FLAC stores audio using lossless compression. This tool decodes that audio and encodes it again with AAC, which discards some information. Changing the extension alone does not carry out the conversion.
| Property | FLAC input | This tool's AAC output |
|---|---|---|
| Extension | .flac | .aac |
| Audio encoding | FLAC | AAC-LC |
| File structure | FLAC stream and metadata | ADTS-framed AAC stream |
| Compression | Lossless | Lossy |
| Precision | Preserves the samples stored in the FLAC | Does not guarantee identical decoded samples |
| Main purpose here | Source for preservation or editing | Copy for a destination that accepts standalone AAC |
AAC describes an audio codec; ADTS describes how the encoded frames are packaged. The FFmpeg format documentation identifies ADTS as a format for one AAC stream. A player that supports AAC inside an MP4 or M4A file may not accept a standalone .aac file, so check both the codec and the required file format.
When a FLAC to AAC conversion is useful
Supply a standalone AAC file
If an import specification explicitly requests .aac or ADTS, this page produces that kind of audio file. Confirm any additional sample-rate, channel, and duration requirements before delivery. An extension match alone does not establish that every requirement has been met.
Prepare a listening or review copy
AAC can provide a compressed copy for someone who accepts this format and does not need the FLAC source. Check the actual size and listen to representative passages. Preserve the FLAC for final editing instead of repeatedly converting the AAC between lossy formats.
Test compatibility with an audio workflow
An application may accept AAC but have difficulty with your FLAC. Convert a representative file and try importing the downloaded result before preparing more files. If the original FLAC already works, conversion may be unnecessary and will not improve its sound.
How to convert FLAC to AAC online
- Upload one FLAC. Select or drag in a complete
.flacfile up to 200MB and 30 minutes. Wait until its recording, export, or download has finished before uploading. - Start conversion. Wait for the upload to finish, then start the task. AAC is already selected; the page uses preset encoding parameters.
- Check and download. Preview the AAC if your browser supports it, download the
.aac, and open it in the application where you intend to use it.
Each task processes one file. There is no batch upload, playlist import, or conversion from a webpage address. A FLAC album with cue information is still one input file; this tool does not split it into individual songs.
Can FLAC to AAC be lossless?
No. AAC output is lossy, including when the FLAC input is 16-bit or 24-bit. A result can sound very close to the source without preserving every audio sample. Keeping the same sample-rate or channel display does not prove lossless conversion.
The service uses an AAC-LC preset with a 192kbps bitrate target. Actual average bitrate can differ, particularly with short recordings or low sample rates. The LC in AAC-LC stands for Low Complexity. The FFmpeg codec documentation distinguishes this profile from other AAC profiles. This page has no HE-AAC, lossless, quality-slider, bitrate, sample-rate, channel, or bit-depth options.
Compare the files at similar playback volume. Listen to sustained notes, sharp attacks, quiet passages, and the beginning and end of the recording. Conversion does not remove noise, repair clipping, or restore missing audio. It also does not guarantee uninterrupted loops or identical timing in every receiving application.
Use the FLAC for later exports. Turning the AAC back into FLAC would store the decoded AAC audio, but it would not reconstruct the information lost during encoding. A higher bitrate or a larger output file does not change that limitation.
Will the AAC be smaller than the FLAC?
It often will be for ordinary music or recordings, but there is no fixed reduction ratio. FLAC compression depends on the content; silence or repetitive sound may compress very efficiently. Short files also give headers and metadata a greater share of the total size. Neither the extension nor the encoding target guarantees a smaller result.
For four minutes of audio, an actual average of 192kbps represents about 5.76MB of audio data. At 128kbps, the same duration represents about 3.84MB. Use audio data size (MB) ≈ average bitrate (kbps) × duration (seconds) ÷ 8000 for the calculation. These decimal-MB examples exclude ADTS frame headers and other overhead; they are not measured results or selectable settings.
Check the downloaded size against the destination's limit. The 200MB limit applies to the source you upload, even if you expect the AAC to be much smaller. Duration is a separate limit, so a compact FLAC can still exceed 30 minutes.
If uploading, conversion, or playback fails
If a duration-reading error prevents upload, check the source in a FLAC-compatible player and confirm that the export or download is complete. Another browser may help with input-reading problems. A valid .flac filename alone does not prove that its audio is readable.
If conversion fails, check the source's audio properties and whether the original application can export a suitable, complete file. Renaming the extension does not repair damage or alter the encoding. The service must be able to decode the actual audio within the size and duration limits.
If a completed AAC will not play in the browser, download it and try an application that explicitly accepts standalone AAC or ADTS. Verify duration, channel count, and channel layout after import. Check tags, artwork, and cue information separately; the tool does not guarantee complete metadata transfer or split an album into tracks.
Frequently asked questions
Is this FLAC to AAC converter free?
Yes. No account or credits are required. Each task accepts one FLAC file up to 200MB and 30 minutes. Batch upload and automatic splitting of longer files are not available.
Can I convert FLAC to AAC without losing quality?
Not losslessly. This page uses lossy AAC encoding, so it cannot preserve every original sample. A difference may be difficult to hear, but that does not make the conversion lossless. Keep the original FLAC for exact preservation or later edits.
Is the output AAC, M4A, or ALAC?
It is AAC-LC audio in an ADTS file with an .aac extension. This page does not output M4A or ALAC. Confirm that the receiving application accepts standalone AAC, not just AAC inside another container.
Can I choose 128kbps, 256kbps, or another quality setting?
No. The page uses a preset 192kbps target without manual bitrate, quality, sample-rate, channel, or bit-depth controls. The actual average bitrate and file size can vary with the source; the target is not an exact output guarantee.
Will the AAC always be smaller?
No. Duration, source compression, actual output bitrate, and file overhead all matter. FLAC can compress some sounds very efficiently. Check the actual download rather than relying on a fixed size ratio.
What if the browser cannot preview the input or result?
If an input-duration error blocks upload, check the FLAC in a compatible application and try another browser. If conversion has completed, download the AAC and use a player that supports standalone ADTS AAC. Input reading and output playback are separate compatibility checks.
Are tags, artwork, and album track boundaries preserved?
Complete preservation is not guaranteed. Inspect the downloaded file in its destination application. The tool creates one audio file and does not use cue information to split an album into tracks; keep the FLAC if you need those details.