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Convert MP3 to M4A Online — Apple Format Compatibility

Convert MP3 to Apple's native M4A format for seamless iTunes and iOS playback.

Drop up to 50 files at once — no install, no sign-up required.

Drop MP3 Files Here

50 MB or 2 hours per file Up to 50 files (2 GB limit) 3 parallel conversions 1 credit per 5 minutes

Encrypted EU Servers Auto-delete 1h

Median MP3 → M4A time (last 10k jobs): 1.3s per minute

How it works

  1. 1 · Drop your files

    Drag & drop or choose MP3 files. No account required—paid plans unlock bigger batches, higher limits, and priority queues.

  2. 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. 3 · Download & auto-delete

    Grab your M4A 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.

M4A (MPEG-4 Audio) is Apple's container format for AAC-encoded audio, introduced with iTunes in 2001. AAC itself was standardized by MPEG in 1997 (MPEG-2) and enhanced in 1999 (MPEG-4), achieving compression ratios of 8:1 to 12:1. M4A has become synonymous with Apple's ecosystem—it's the default for iTunes purchases, Apple Music downloads, and iPhone voice memos. At equivalent bitrates, AAC delivers better quality than MP3, with 256 kbps M4A typically matching 320 kbps MP3.

Learn more: M4A on Wikipedia

M4A supports sample rates up to 96 kHz and up to 48 audio channels, including surround sound configurations. The main limitation is compatibility—while modern devices handle M4A well, older hardware and some software (particularly on Windows and Linux) may not support it natively. For universal playback, MP3 remains the safer choice. M4A excels for Apple-centric workflows: syncing to iPhone, organizing in iTunes/Music app, or archiving Apple Music downloads.

Frequently Asked Questions

What is the difference between MP3 and M4A?

MP3 uses older MPEG-1 Layer 3 compression. M4A uses modern AAC encoding in an MPEG-4 container. AAC generally achieves better quality at the same bitrate. M4A is the native format for Apple devices and iTunes.

Will converting MP3 to M4A improve audio quality?

No, it won't improve quality. Since MP3 is already compressed, converting to M4A re-encodes the audio. You get a different container and codec, but the quality lost during original MP3 encoding is gone forever. For best quality, start from lossless FLAC sources instead.

Why would I convert MP3 to M4A?

Compatibility with Apple devices. M4A is the native format for iPhone, iPad, iTunes, and Apple Music. Some apps and workflows require M4A files. M4A also supports features like gapless playback that MP3 handles inconsistently. Need the reverse? Convert M4A to MP3.

What AAC settings do you use?

We encode at 320 kbps AAC (maximum quality) for excellent audio fidelity. The output uses the 'ipod' container format for maximum Apple device compatibility, with faststart enabled for streaming.

How do file sizes compare between MP3 and M4A?

At the same bitrate, M4A files are similar in size to MP3 files (within 10-15%). AAC is more efficient than MP3, so you could use a lower bitrate for equivalent quality-but we keep them matched for predictable output sizes.

What happens to ID3 tags and metadata?

Text metadata (title, artist, album, genre) is preserved and mapped to iTunes metadata. Embedded cover art is stripped during conversion—keep your original MP3 if cover art is important.

How long can my audio files be?

Duration limits depend on your plan: Guest/Free: 120 minutes, Pro: 600 minutes (10 hours), Business: 3000 minutes (50 hours). This accommodates everything from short clips to full audiobook chapters and podcasts.

What are the limits for this converter?

TierMax File SizeMax Files/BatchParallel Processing
Free50 MB50 files3 at once
Pro500 MB200 files6 at once
Business2048 MB1000 files10 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:

TierDaily LimitMonthly Limit
Free50 credits/day
Pro10,000 credits/month
Business30,000 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.

Choose Your Plan

Limits shown for MP3 to M4A conversion. One subscription unlocks the entire Tools.FAST Network. Plans cover Convert.FAST, Compress.FAST, PDF.FAST (soon), and all future tools.

Monthly Annual 4 Months Free

Free

$0

For occasional personal use

  • 50 MB per file
  • 50 files per batch
  • 3 parallel conversions
  • 50 credits/day
  • Standard priority
  • Email support
Sign Up Free

No sign-up required. Create an account for your own credit pool.

Popular

Pro

$9 /month

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

$19 /month

1 seat

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 M4A

Latest improvements to this converter

Last updated December 15, 2025
Dec 15, 2025

Initial release of MP3 to M4A converter with AAC encoding.