Why are my AIFF files so large?

AIFF stores uncompressed PCM audio, meaning every sample of the recording is written to the file in raw form with nothing discarded. For a 44.1 kHz, 16-bit stereo recording that works out to roughly 10 MB per minute, so a five-minute track reaches around 50 MB. This doesn't mean the format is flawed; it's the price paid for having no quality loss. WAV works on the same principle and produces similar sizes.

Is there quality loss when converting AIFF to MP3?

Yes, and it's unavoidable. AIFF is lossless while MP3 is a lossy format; some audio information is permanently discarded during encoding. At high bitrates like 256-320 kbps, however, that difference is too small to distinguish in most listening environments. What matters is not deleting your original AIFF files, because they are your master copy and cannot be reproduced from an MP3.

What is the difference between AIFF and WAV?

In terms of audio data both store uncompressed PCM, so there is no practical difference in quality between them. The main distinction is their origin: AIFF came from the Apple world and WAV from the Microsoft side, and they differ in how data is arranged inside the file and how metadata is handled. Today nearly all serious software on both macOS and Windows can open either format, so the choice usually comes down to workflow habit.

Can I delete my AIFF files after converting?

We'd advise against it. MP3 is a lossy format; the audio data discarded during conversion cannot be recovered, so even if you produce an AIFF from the MP3 later you won't return to the original quality. Keep your AIFF files archived on a backup drive and use the MP3 copies for everyday listening. That way you'll have a clean source if you ever want to move to a different format.

How to Convert AIFF to MP3: A Step-by-Step Guide

What is AIFF and why convert it?

AIFF is Apple's uncompressed audio format, and in practice it can be thought of as the counterpart to WAV. It holds raw PCM audio data: every sample captured during recording is stored exactly as it was, with no information discarded. That's why it turns up frequently in Logic, GarageBand, and macOS-based audio workflows, as well as in CD audio transfers and as a professional delivery format.

The only drawback of this otherwise excellent structure is size. A 44.1 kHz, 16-bit stereo recording takes up roughly 10 MB per minute. An album's worth of AIFF files quickly reaches gigabytes; putting them on a phone, sending them by email, or uploading them to the web stops being practical.

Converting to MP3 is exactly what addresses this: AIFF is a production and archive format, MP3 is a distribution format.

This conversion has something distinctive about it

Most audio conversions move from one lossy format to another, and there the main concern is compounding losses. Moving from AIFF to MP3 is different: here the source is lossless, and the conversion is the first moment of real loss that recording experiences.

That has two important consequences:

First, bitrate selection genuinely matters. When converting from a lossy source, choosing a high bitrate has limited benefit because what was lost is already lost. But when converting from a lossless source, the bitrate you choose directly determines how good the output will be. This is the one moment where you have a real say in the quality.

Second, you must keep the original. Producing an AIFF from an MP3 is possible but pointless: the lost information doesn't return, you simply place a small file into a large container. Your AIFF file is your master copy. Deleting it is an irreversible decision.

Step-by-step conversion

1. Finish the recording before converting

Complete all editing — cuts, level adjustment, noise cleanup, effects — on the AIFF. If you edit after converting to MP3 and save again, you add a second round of compression and drop the quality for no reason. The rule is simple: edit in a lossless format, convert as the final step.

2. Upload your file

Open our AIFF to MP3 converter and drag your file in. Because it runs in the browser, there's no software to install.

3. Choose a bitrate to match the content

Since you're converting from a lossless source, this choice directly determines the result:

320 kbps: The safest choice for music and content you'll publish. For anyone wanting near-archive quality or listening on good equipment.
192-256 kbps: A balanced middle ground between size and quality. More than enough for everyday listening and general sharing.
128 kbps and below: Not recommended for music. Perfectly adequate for speech recordings.
96-128 kbps mono: Ideal for single-channel speech content such as interviews, lectures, or meeting recordings; it shrinks the file dramatically.

If a variable bitrate (VBR) option is available, consider it: because it allocates more data to dense passages, it generally gives a slightly better result at the same average size.

4. Check the channel setting

If the source is a stereo music recording, leave it in stereo. For a speech recording made with a single microphone where both channels carry the same audio, dropping to mono nearly halves the file and costs you nothing. Converting stereo music to mono, on the other hand, permanently destroys the stereo image.

5. Convert and tag

Once processing is done, download your MP3. AIFF files sometimes carry limited metadata, so your output may arrive without artist and album information. If you're adding it to a music library, fill in those fields with a tag editor.

6. Verify the result

Open the file and listen to a few seconds from the beginning, middle, and end. Check that the duration matches the source and that there are no dropouts or artifacts. If you chose a low bitrate, it's worth testing once in the intended listening environment — phone, car stereo, headphones.

What file sizes to expect

An hour of 44.1 kHz, 16-bit stereo AIFF comes to roughly 600 MB. The same recording as MP3 drops to approximately: 55 MB at 128 kbps, 85 MB at 192 kbps, and 140 MB at 320 kbps. This is why the impact of bitrate selection is so pronounced on long recordings.

If you want to reduce size while staying lossless, FLAC offers a middle path: it stores exactly the same audio data as AIFF at roughly half the size. Its device compatibility, however, isn't as broad as MP3's.

Common mistakes

Deleting the original AIFF files. The mistake that causes the most regret. Back up your master copy.
Editing on the MP3. Every re-save is another round of loss.
Giving speech recordings 320 kbps. It takes up space needlessly and is inaudible by ear.
Expecting quality from raising the sample rate. Detail that isn't in the source cannot be manufactured.

In summary

Converting AIFF to MP3 is the step that turns a lossless master into something shareable. Because this is the recording's first moment of real loss, bitrate selection genuinely makes a difference here — 256-320 kbps for music and 96-128 kbps for speech are sensible ranges. Finish your editing before converting, test the result in the target environment, and above all keep your original AIFF files archived. As long as the master copy remains in your hands, you can always produce a clean output in a different format.