Convert your .mp3 files to .aac format online for free. No software to install. Fast, secure, and easy.
Pro account required for audio & video
Drag and drop your .mp3 file or click to browse.
Select AAC as your output format.
Click Convert and download your .aac file.
Converting between MP3 and AAC changes the codec used for compression. AAC typically delivers better audio quality than MP3 at the same bitrate.
MP3 (MPEG Audio Layer III, introduced in 1993) uses Lossy (psychoacoustic model + MDCT) compression. AAC (Advanced Audio Coding, introduced in 1997) uses Lossy (MDCT-based with TNS and PNS tools) compression. MP3 browser support: Universal. AAC browser support: Universal.
Both MP3 and AAC use lossy compression. Converting between two lossy formats involves decoding the MP3 file and re-encoding it as AAC, which introduces an additional generation of compression. To minimize quality loss, use the highest practical quality setting for the AAC output.
Typical MP3 file size: A 4-minute song at 192 kbps: ~5.5 MB; at 320 kbps: ~9.2 MB. Typical AAC file size: A 4-minute song at 256 kbps AAC-LC: ~7.3 MB.
When converting between two lossy formats, use the highest practical bitrate for the output to minimize the quality impact of double compression. If possible, convert from the original lossless source instead of from a previously compressed file.
Convert MP3 to AAC with 3 free conversions per day. No hidden fees.
Create a free account in 10 seconds and start converting immediately. No credit card required.
Files are encrypted during transfer, processed on secure servers, and deleted immediately after conversion.
Convert files from any device — desktop, tablet, or phone. No software to install, works in any modern browser.
SquishConvert supports over 358 file conversion combinations across images, documents, audio, and video.
Your converted .aac file maintains the best possible quality. No unnecessary compression or quality loss.
Audio conversion requires a Pro account. See pricing — starting at $4.99/month
You get 3 free conversions per day. Audio conversions require a Pro account.
Most files convert in under 10 seconds. Larger files may take a bit longer depending on size.
Yes. Files are encrypted during transfer, processed on secure servers, and deleted immediately after conversion. We never store your files.
Currently, SquishConvert converts one file at a time. Batch conversion is coming soon — stay tuned!
Free users can convert files up to 10 MB. Pro users can convert files up to 500 MB.