Convert MP3 to AAC Online — Raw ADTS Format
Convert MP3 to AAC (ADTS) for streaming and hardware device compatibility.
Drop up to 50 files at once — no install, no sign-up required.
Drop MP3 Files Here
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How it works
- 1 · Drop your files
Drag & drop or choose MP3 files. No account required—paid plans unlock bigger batches, higher limits, and priority queues.
- 2 · We convert securely
Processed on our dedicated servers. Encrypted in transit & at rest. We never store filenames—only file types & sizes for accounting.
- 3 · Download & auto-delete
Grab your AAC files in seconds. Files delete automatically after 1 hour. Delete anytime after downloading with one click.
MP3 (MPEG-1 Audio Layer III) revolutionized digital audio when it was standardized in 1993 by the Fraunhofer Society. Using psychoacoustic compression, MP3 removes audio frequencies that humans typically cannot perceive, achieving 10:1 compression or better while maintaining excellent subjective quality. MP3 supports sample rates from 8-48 kHz and 16-bit audio. At 256 kbps, most listeners cannot distinguish MP3 from the original source in blind tests.
Learn more: MP3 on Wikipedia
MP3 remains the most universally compatible audio format, supported by every music player, smartphone, computer, and web browser. While newer codecs like AAC and Opus offer marginally better compression efficiency, MP3's ubiquitous support makes it the safest choice for sharing audio. The format's patents expired in 2017, making it completely free to use without licensing concerns.
AAC (Advanced Audio Coding) is the successor to MP3, standardized by MPEG in 1997 and subsequently adopted as the default format for YouTube, Apple Music, and most streaming platforms. Achieving compression ratios of 8:1 to 12:1, AAC delivers better quality than MP3 at the same bitrate—128 kbps AAC typically matches 160-192 kbps MP3. It's the underlying codec in M4A files (AAC audio in an MP4 container) and the audio component of most video files.
Learn more: AAC on Wikipedia
Raw AAC files (with .aac extension) are less common than containerized versions (.m4a, .mp4), but they're used in broadcast, streaming pipelines, and as extracted audio from video. AAC supports sample rates up to 96 kHz and up to 48 audio channels, including 5.1 and 7.1 surround configurations—making it suitable for professional multichannel content. For maximum compatibility with minimal quality loss, AAC at 256 kbps is often the sweet spot between MP3's universality and FLAC's fidelity.
Frequently Asked Questions
What is the difference between MP3 and AAC?
What is ADTS AAC format?
What is the difference between AAC and M4A?
Will converting MP3 to AAC improve audio quality?
Why would I convert MP3 to AAC?
What AAC settings do you use?
How long can my audio files be?
What are the limits for this converter?
| Tier | Max File Size | Max Files/Batch | Parallel Processing |
|---|---|---|---|
| Free | 50 MB | 50 files | 3 at once |
| Pro | 500 MB | 200 files | 6 at once |
| Business | 2048 MB | 1000 files | 10 at once |
Note: File size limits are specific to this converter. Batch and parallel processing limits apply to all images converters site-wide. See all converter limits →
How are credits calculated for this conversion?
Cost: 1 credit per 5 minutes
How it works:
- Files up to 5 minutes: 1 credit (minimum)
- 6-10 minutes: 2 credits
- 11-15 minutes: 3 credits
- 16-20 minutes: 4 credits
Example: A 10-minute file = 1 credit. A 180-minute (3h) audiobook = 36 credits.
Why per-minute? Audio conversion time scales with content duration, not file size. Longer audio requires proportionally more processing.
What are my daily and monthly credit limits?
Credit allocations vary by account tier:
| Tier | Daily Limit | Monthly Limit |
|---|---|---|
| Free | 50 credits/day | — |
| Pro | — | 10,000 credits/month |
| Business | — | 30,000 credits/month |
Daily credits (Free tier, including guests) reset every day at midnight UTC. Monthly credits (Pro & Business) reset on your billing cycle date.
Note: With 1 credit per 5 minutes, audio files under 5 MB cost 1 credit each. Pro users can convert 10,000 audio files per month.
Answers at a Glance
Quick answers to common questions.
- Are my files secure?
- How long do you keep my files?
- What metadata do you keep?
- What happens after I drop a file?
- Why are conversions so fast?
- How do you measure performance?
- What are the exact limits for each plan?
- Can I process files in bulk?
- Why did my file fail to convert?
- Do you use my files to train AI?
Choose Your Plan
Limits shown for MP3 to AAC conversion. One subscription unlocks the entire Tools.FAST Network. Plans cover Convert.FAST, Compress.FAST, PDF.FAST (soon), and all future tools.
Free
For occasional personal use
- 50 MB per file
- 50 files per batch
- 3 parallel conversions
- 50 credits/day
- Standard priority
- Email support
No sign-up required. Create an account for your own credit pool.
Pro
For independent work
- 500 MB per file
- 200 files per batch
- 6 parallel conversions
- 10,000 credits/month across Tools.FAST
- High priority
- Email & chat support
- One subscription for the entire Tools.FAST network
Business
For production scale
- 2 GB per file
- 1000 files per batch
- 10 parallel conversions
- 30,000 credits/month across Tools.FAST
- Add seats to invite team members
- Highest priority
- Priority email & chat support
- One subscription for the entire Tools.FAST network
How Credits Work
- Usually 1 credit per conversion. Exact cost shown before you start.
- Credits refresh monthly on your billing cycle.
- Unused credits roll over, capped at your plan's monthly amount.
- One subscription, all sites. Works across Convert.FAST, Compress.FAST, and future tools.
What's New in MP3 to AAC
Latest improvements to this converter
Initial release of MP3 to AAC converter with raw ADTS AAC output.