If you care about perfect audio quality and have storage to spare, choose FLAC for your master library. If you need small files that play on every device, choose MP3 — and convert your FLACs to MP3 for portable use. The right answer depends on your ears, your hard drive, and where you listen.
When to Use FLAC
FLAC (Free Lossless Audio Codec) compresses music without losing a single bit of data. It’s the format archivists and audiophiles choose because it’s a perfect digital copy of the original CD or studio master. If you’re ripping your CD collection or buying high-resolution downloads, FLAC is the safe long-term choice: you can always convert it to any other format later without re-ripping.
FLAC files are typically 50–60% the size of the original WAV, but still much larger than MP3 — a 4-minute song might be 25–30 MB. That’s fine on a 1 TB drive, but it adds up fast on a phone. FLAC also isn’t supported by every device: older car stereos, some smart speakers, and many portable players won’t read it. If you’re building a home library on a computer or NAS, FLAC is the way to go.
When to Use MP3
MP3 is the universal format. It plays on virtually everything — phones, tablets, car stereos, smart TVs, web players, and even cheap earbuds. A 320 kbps MP3 sounds nearly identical to a CD for most listeners, especially on earbuds or in noisy environments. At 128 kbps it’s fine for spoken word or background music.
The big advantage is size: a 4-minute MP3 at 320 kbps is about 10 MB, and at 128 kbps it’s around 4 MB. That means you can fit thousands of songs on a phone. If you’re creating a playlist for your commute or a workout, MP3 is the practical choice. It’s also the safest format to send to friends or upload to services that don’t accept FLAC.
Why Convert in Your Browser Instead of Using an Upload Site
Most online converters work by uploading your file to a server, converting it there, and then having you download the result. That means your music — possibly your whole album — sits on someone else’s machine, even if only for a minute. With Audio Converter, everything happens locally in your browser. Your FLAC file never leaves your device. There’s no upload, no waiting for a server queue, and no risk of your private recordings being copied.
Because the conversion is on-device, there are no file-size caps and no watermarks. You can convert a full concert recording without worrying about a limit. And since the tool runs in your browser, it works on any operating system — Windows, macOS, Linux, or ChromeOS.
Common Mistakes to Avoid
- Converting FLAC to a lossy format twice. If you convert FLAC to MP3, keep the FLAC original. Never convert an MP3 back to FLAC — you’ll just get a large file with the same quality as the MP3.
- Using too low a bitrate. For music, 320 kbps MP3 is recommended. Below 192 kbps, you’ll notice a loss of high frequencies, especially with cymbals and strings.
- Not checking device compatibility. Before you delete your FLACs, make sure the player you’re targeting actually supports MP3 (it almost always does) or FLAC (it might not).
- Assuming FLAC is always better. If you listen on Bluetooth earbuds or in a car, the compression of the playback system masks any difference. MP3 is perfectly fine there.
Which One Should You Store Long-Term?
If you have the disk space, keep FLAC as your master and make MP3 copies for portable use. That way you’ll never have to re-rip or re-download your music. If storage is tight, MP3 at 320 kbps is a reasonable compromise that most people can’t distinguish from lossless in a blind test.
The Bottom Line on File Size
File size is the main trade-off. FLAC files are typically 3–5 times larger than MP3 at 320 kbps. If you’re ripping 1,000 CDs, that’s the difference between a few hundred gigabytes and a few dozen. Choose based on your storage and your listening habits.
How to Get a Portable Copy
When you’re ready to make a portable copy, use Audio Converter to convert your FLAC files to MP3. It’s free to use, with 5 exports per day without an account and 15 per day with a free account. If you need more, the Pro plan removes the daily limit and covers all 40 Alvseike tools. And because everything runs locally, your music stays private.