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What "Lossless" Really Means: Spotify, Apple Music and the Numbers Behind Hi-Res Audio

·8 min read

In September 2025 Spotify announced lossless audio for Premium subscribers, up to 24-bit/44.1 kHz FLAC. Apple announced lossless audio for Apple Music in 2021. The word is easy to misread, so this article starts with what lossless actually promises. It then looks at what the two services say about their own quality levels, how much data each level represents, why Bluetooth changes the picture, and what the argument over hi-res audio looks like.

Every claim about a service or a standard comes from that company's or standards body's own publication, linked at the end. Calculations are ours and are labelled as such.

What "Lossless" Promises, and What It Does Not

The FLAC specification, RFC 9639, defines lossless compression as reducing the storage needed for data without removing or irreversibly altering any of it. In other words, decompressing losslessly compressed information returns exactly the original data. Lossy compression, by contrast, returns an approximation of the original data.

For audio, that makes a lossless codec such as FLAC or Apple's ALAC a smaller package for PCM. Decode it and you get back the same samples that went in. Apple's 2021 announcement describes ALAC in the same terms: Apple says it uses ALAC to preserve every single bit of the original audio file. Our guide to what PCM audio is explains what those samples are.

Two things follow from the definition. First, lossless preserves the file a service starts with; it cannot add anything that file does not contain. Second, lossless describes the codec, not the whole path to your ears. The Bluetooth section below shows why that matters.

What Spotify Announced

Spotify's announcement of 10 September 2025 says:

  • Premium subscribers can stream tracks in up to 24-bit/44.1 kHz FLAC.
  • Lossless joins the existing Low, Normal, High and Very High levels, and each level can be set separately for Wi-Fi, cellular and downloads.
  • The rollout is gradual. An update dated 6 October 2025 says it is available to Premium users in more than 50 markets.
  • You turn it on per device under Settings & Privacy → Media Quality, and a Lossless indicator shows in the Now Playing view or bar and in the Connect Picker when it is active.
  • It works on mobile, desktop and tablet, and on many devices that support Spotify Connect, including Sony, Bose, Samsung and Sennheiser. The announcement said support for Sonos and Amazon devices would arrive the following month.

Spotify gives 24-bit/44.1 kHz as a maximum ("up to"). The announcement does not state that every track is delivered at that resolution.

How Apple Music Compares

Apple's announcement of 17 May 2021 described a catalogue of more than 75 million songs in lossless audio, using ALAC. Its lossless tier starts at CD quality, which is 16-bit at 44.1 kHz, and goes up to 24-bit at 48 kHz, playable natively on Apple devices. A separate Hi-Resolution Lossless tier goes up to 24-bit at 192 kHz and requires external equipment, such as a USB digital-to-analogue converter (DAC). Apple's current support page lists, platform by platform, when an external DAC is needed to listen at sample rates above 48 kHz.

ServiceLossless codecHighest resolution stated
SpotifyFLAC24-bit/44.1 kHz
Apple MusicALAC24-bit/192 kHz (Hi-Res Lossless); 24-bit/48 kHz in the standard Lossless tier

We compare only these two because they are the services whose own announcements we checked. Other services publish their own figures.

How Much Data Is That?

The uncompressed data rate of PCM is the sample rate times the bit depth times the number of channels. For stereo, that gives these figures (our calculation, with 1 MB meaning 1,000,000 bytes):

QualityUncompressed data ratePer minute
16-bit / 44.1 kHz (CD quality)1,411.2 kbit/sabout 10.6 MB
24-bit / 44.1 kHz2,116.8 kbit/sabout 15.9 MB
24-bit / 48 kHz2,304 kbit/sabout 17.3 MB
24-bit / 96 kHz4,608 kbit/sabout 34.6 MB
24-bit / 192 kHz9,216 kbit/sabout 69.1 MB

So 24-bit/192 kHz is about 6.5 times the data of CD quality (our calculation). Real lossless files are smaller than these figures, because FLAC and ALAC compress. RFC 9639 explains that FLAC works because samples in audio signals tend to be highly correlated with their close neighbours, so how much smaller a file gets varies from track to track (our inference, not a figure from the RFC). We have not quoted streaming bitrates for the services, because Spotify's announcement does not state them. Our guide to sample rate and bit depth covers where these numbers come from.

Why Bluetooth Is the Weak Link

Spotify recommends streaming lossless on Wi-Fi, using wired headphones or speakers or a non-Bluetooth connection such as Spotify Connect. Its reason is that Bluetooth does not currently provide enough bandwidth to transmit lossless audio, so the signal has to be compressed before it is sent.

Apple makes a similar point on its support page. AirPods 3 or earlier, AirPods Pro 1, AirPods Pro 2 with the Lightning charging case, AirPods Max and most Beats wireless headphones use Apple's AAC Bluetooth codec, and Apple states that Bluetooth connections are not lossless. The same page says AirPods Max 1 (USB-C) and AirPods Max 2 can play lossless audio when connected with a USB-C cable.

For scale, Sony's LDAC page shows the standard Bluetooth A2DP link at 328 kbit/s at 44.1 kHz, and LDAC at up to 990 kbit/s, adapting between 330, 660 and 990 kbit/s. The uncompressed CD-quality PCM in the table above is 1,411.2 kbit/s. A bitrate alone does not tell you whether a link is lossless, because lossless compression lowers the number too, so rely on what the manufacturer and the service say about the specific codec. Spotify says Bluetooth currently cannot carry lossless audio, and Apple says the same of its AAC Bluetooth connections.

Is Hi-Res Worth It? One Engineering View

An article from Xiph.Org, signed "Monty" and dated March 2012, is called "24/192 Music Downloads... and why they make no sense". In summary, it argues:

  • Playback fidelity of 24-bit/192 kHz is slightly inferior to 16/44.1 or 16/48, and the files take about six times the space.
  • The range of 20 Hz to 20 kHz is a generous description of what people hear. Ultrasonic content is inaudible and can cause intermodulation distortion in playback equipment that was not designed to reproduce it.
  • 16-bit PCM has a dynamic range of 96 dB by the common definition of 6 dB per bit, but the article argues that with shaped dither the effective dynamic range reaches about 120 dB in practice.
  • More than 16 bits has real uses in recording and production, but the article says 24-bit is no help for playback. It does not harm fidelity, it just wastes space.

For context, RFC 6716 notes that the sampling theorem allows a bandwidth up to half the sampling rate, so 44.1 kHz can represent content up to 22.05 kHz (our arithmetic). The same RFC calls 20 kHz the generally accepted upper limit of human hearing. The Opus 1.6 release demo page (see our Opus 1.6 article) says 48 kHz audio is "good enough for everyone" and describes 96 kHz Opus HD as being for other uses such as sensors and ultrasonics.

This is one published argument by a single author. It is not a settled consensus, and we have not reproduced its listening tests. We include it because it explains what the extra bits and samples in the table above actually add. Whether you can hear a difference depends on your equipment, your hearing and the quality of the master.

Practical Takeaways

  • Lossless guarantees that decoding gives back the same PCM samples, and nothing more. That is the definition in RFC 9639.
  • Check the connection. Spotify says Bluetooth currently cannot carry lossless audio and Apple says its AAC Bluetooth connections are not lossless, so use Wi-Fi, a wired connection or a USB connection where the service supports it.
  • Higher numbers mean more data. By our calculation, 24-bit/192 kHz is about 6.5 times the uncompressed data of CD quality.
  • Treat claims about audible benefits from hi-res formats as a matter of debate, and judge for yourself on your own equipment.
  • You can check your own headphones and speakers with our guide to testing audio equipment with a tone generator.

Summary

Lossless means the decoded PCM is identical to what was encoded, which is a promise about the codec and not about the whole listening chain. Spotify's lossless tier tops out at 24-bit/44.1 kHz FLAC, Apple Music's Hi-Res Lossless tier at 24-bit/192 kHz, and Spotify says Bluetooth currently cannot carry lossless audio while Apple says its AAC Bluetooth connections are not lossless. The data-rate table shows what each step up costs in bandwidth and storage, and the Xiph.Org article shows that whether the extra resolution is audible is still argued over.

Sources and verification

The facts in this article were checked against the primary sources below on . Figures described as our own calculation are derived from those sources. If you spot a mistake, please tell us through the contact page.