RunConvert

FLAC to AAC Converter

Convert FLAC to AAC online for free. Fast, secure, and high-quality conversion with no sign-up or software required.

Free to useNo file stored beyond 1 hourEncrypted over TLS 1.2/1.3No watermarks

How it works

Three steps to your converted file

Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.

01

Upload your file

Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.

02

Choose an output format

Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.

03

Convert & download

Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.

What is a FLAC file?

The Free Lossless Audio Codec (FLAC) is an open-source audio coding format developed by the Xiph.Org Foundation that compresses digital audio without any loss of data (bit-perfect preservation). It employs linear prediction and Rice coding (Golomb-Rice) rather than the perceptual psychoacoustic modeling used in MP3 or AAC. The format structure consists of the 'fLaC' stream marker, metadata blocks (Streaminfo, Vorbis comments for tags, Seekpoints), and audio frames, typically achieving compression ratios of 50-70% compared to raw PCM WAV files.

How to open a FLAC file

FLAC enjoys extensive native support on modern platforms, including Windows 10/11, Android, and macOS (starting with macOS High Sierra). For older systems or advanced playback control, software such as Foobar2000 (Windows) or Vox (macOS) is recommended. The VLC media player is a universal solution for all operating systems, handling FLAC streams and associated metadata seamlessly.

FLAC Technical Info

Full Name
Free Lossless Audio Codec
Developed By
Josh Coalson / Xiph.Org Foundation
Initial Release
2001
MIME Type
audio/flac

What is an AAC file?

Advanced Audio Coding (AAC) is a lossy digital audio compression standard defined by ISO/IEC 13818-7 (MPEG-2) and ISO/IEC 14496-3 (MPEG-4). Developed by a consortium including Bell Labs, Fraunhofer IIS, and Dolby Laboratories as the successor to MP3, AAC utilizes the Modified Discrete Cosine Transform (MDCT) algorithm and perceptual noise shaping to discard imperceptible signal components. It supports up to 48 audio channels, arbitrary sample rates, and utilizes extensions such as Spectral Band Replication (SBR) to achieve higher fidelity at lower bitrates than predecessor formats.

How to open an AAC file

AAC serves as the default audio container for Apple's iTunes and iOS devices, ensuring native support within the macOS Core Audio framework and Apple Music. Windows 10 and 11 provide native decoding support via the Groove Music and Windows Media Player applications. For cross-platform playback or advanced stream analysis, users should utilize VLC Media Player or FFmpeg, which contain the necessary libavcodec libraries to decode AAC streams without external codec packs.

AAC Technical Info

Full Name
Advanced Audio Coding
Developed By
Bell Labs, Fraunhofer IIS, Dolby, Sony, Nokia
Initial Release
1997
MIME Type
audio/aac

Why RunConvert

The fastest way to convert any file

Purpose-built for speed, privacy, and breadth of format support.

Convert FLAC to AAC in seconds

Every FLAC to AAC conversion runs on our servers, so your device stays fast and the output quality stays intact.

Fast, cloud-powered

No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.

Secure & private

Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.

Free - no account needed

Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.

Developer API

Convert FLAC to AAC via API

Automate FLAC to AAC conversions in three steps: create a job, upload your file, then poll for the result.

# 1. Create job
curl -X POST https://api.runconvert.com/v3/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "tag": "flac-to-aac",
    "tasks": {
      "upload-file": {
        "operation": "import/upload"
      },
      "convert": {
        "operation": "convert",
        "input": "upload-file",
        "output_format": "aac"
      },
      "export-result": {
        "operation": "export/url",
        "input": "convert"
      }
    }
  }'

# 2. Upload your file (use upload_url from the response)
curl -X PUT "$UPLOAD_URL" --upload-file input.flac

# 3. Poll for result
curl https://api.runconvert.com/v3/jobs/$JOB_ID?include=tasks \
  -H "Authorization: Bearer YOUR_API_KEY"

Replace YOUR_API_KEY with your RunConvert API key. Get your free API key at runconvert.com/api.