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iMac (Retina 4K, 21.5-inch, Late 2015)

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Quick look

Price
£1,1992launch price
Chip
Core i53.1GHz quad-core Intel
CPU
4-coreCPU
GPU
Not available3GPU
Memory
8GBmemory, base
Storage
1TBstorage, base
Display
21.5-inchdisplay
Released
13 October 20152Released
Security updates
16 September 20244Security updates ended

Each figure is from the source marked1 unless it carries its own number.

528 mm450 mm
Drawn to scale from the published dimensions below: the front face. Outline only — the corner radius, where the display sits in the face and the stand’s width are our drawing conventions, not measurements; the display rectangle is Apple’s diagonal at its aspect ratio.

Specifications

Body

Dimensions
450 x 528 x 175 mm
Weight
5.68 kg
Ports
Two Thunderbolt 2 ports, four USB 3 ports, SDXC card slot, Gigabit Ethernet (RJ-45), 3.5 mm headphone jack
Thunderbolt ports
2
Thunderbolt version
Thunderbolt 2
USB-A ports
4
HDMI
No HDMI port.5
SD card slot
Yes
Headphone jack
Yes
Keyboard
Magic Keyboard
Touch ID
No Touch ID.5

Display

Display size
21.5 in
Resolution
4096 x 2304
Display type
Retina 4K display with IPS technology
Wide colour (P3)
Yes6

Chip and memory

Chip
3.1GHz quad-core Intel Core i5
Apple silicon
Intel processor, not Apple silicon.7
CPU cores
4
Graphics
Intel Iris Pro Graphics 6200
Chip options
3.1GHz quad-core Intel Core i5 or 3.3GHz quad-core Intel Core i7
Memory (base)
8GB
Memory (maximum)
16GB
Memory options
8GB or 16GB
Memory upgradeable by user
No, as Apple documents8
Storage (base)
1TB
Storage (maximum)
2TB
Storage options
1TB hard drive, 1TB or 2TB Fusion Drive, or 256GB or 512GB flash storage (SSD)9

Connectivity

Wi-Fi
802.11ac Wi-Fi
Bluetooth
4.0
Ethernet
10/100/1000BASE-T Gigabit Ethernet (RJ-45)
External displays (base)
1

Camera and audio

Camera
FaceTime HD camera
Speakers
Stereo speakers
Microphones
Dual microphones

Platform

Shipped with
OS X El Capitan10
Newest macOS
macOS Monterey11
Model identifier
iMac16,211
Part numbers
MK452xx/A12
Model year
2015

Benchmarks

Geekbench 7 (CPU, single-core)
1,08013
Geekbench 7 (CPU, multi-core)
3,12213

An iMac has no battery, so battery rows do not apply.

Software support

Feature updates until
Not available14
endoflife.date lists security support for Monterey as ended
16 September 20244
Basis
endoflife.date’s listed end of security support for Monterey15

Previous and next model

Next model

What changed

Weight
5.68 kg iMac (Retina 4K, 21.5-inch, Late 2015)5.66 kg iMac (Retina 4K, 21.5-inch, 2017)
Ports
Two Thunderbolt 2 ports, four USB 3 ports, SDXC card slot, Gigabit Ethernet (RJ-45), 3.5 mm headphone jack iMac (Retina 4K, 21.5-inch, Late 2015)Two Thunderbolt 3 (USB-C) ports, four USB 3 ports, SDXC card slot, Gigabit Ethernet (RJ-45), 3.5 mm headphone jack iMac (Retina 4K, 21.5-inch, 2017)
Chip
3.1GHz quad-core Intel Core i5 iMac (Retina 4K, 21.5-inch, Late 2015)3.0GHz quad-core Intel Core i5 iMac (Retina 4K, 21.5-inch, 2017)

More on this Mac

Comparisons

Against its own line

Against the rest of the range

Sources

  1. Apple Support (UK) — iMac (Retina 4K, 21.5-inch, Late 2015) - Technical Specification · Default for iMac (Retina 4K, 21.5-inch, Late 2015) · Apple’s figure · read 15 Sep 2026

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  2. Apple Newsroom (UK) — Apple Updates iMac Family with Stunning New Retina Displays · Apple’s figure · read 15 Sep 2026

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  3. Not published by Apple. Pages checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, Late 2015) - Technical Specification; Apple Support (UK) — Identify your iMac model; Apple Newsroom (UK) — Apple Updates iMac Family with Stunning New Retina Displays. Read 9 Oct 2026

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  4. endoflife.date — Apple macOS · third-party figure · read 2 Oct 2026

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  5. No HDMI port. No Touch ID. Checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, Late 2015) - Technical Specification. Read 9 Oct 2026

    ↩

  6. Apple Newsroom (UK) — Apple Updates iMac Family with Stunning New Retina Displays · Apple’s figure · read 3 Oct 2026

    ↩

  7. Intel processor, not Apple silicon. Checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, Late 2015) - Technical Specification. Read 15 Sep 2026

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  8. Apple Support (UK) — Install memory in an iMac · Apple’s figure · read 18 Oct 2026

    ↩

  9. Apple Support (UK) — iMac (Retina 4K, 21.5-inch, Late 2015) - Technical Specification · Apple’s figure · read 11 Oct 2026

    ↩

  10. Apple Newsroom (UK) — Apple Updates iMac Family with Stunning New Retina Displays · Apple’s figure · read 9 Oct 2026

    ↩

  11. Apple Support (UK) — Identify your iMac model · Apple’s figure · read 15 Sep 2026

    ↩

  12. Apple Support (UK) — Identify your iMac model · Apple’s figure · read 18 Oct 2026

    ↩

  13. Geekbench Browser (Primate Labs) · third-party figure · read 11 Oct 2026

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  14. Feature updates: end date not published by Apple. Checked: endoflife.date. Read 2 Oct 2026

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  15. This is endoflife.date’s cycle end for Monterey, not necessarily the day of Apple’s last patch. The newest macOS Apple lists this Mac for is macOS Monterey. endoflife.date records security updates for Monterey as ended on 16 September 2024. Source: endoflife.date. Read 2 Oct 2026

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Not published by Apple

iMac (Retina 4K, 21.5-inch, Late 2015). Apple doesn’t publish for this Mac: colours, pixel density, brightness, refresh rate, nano-texture option, GPU cores, storage upgradeable by user, maximum continuous power. Geekbench 7 Metal: the Mac chart has no Metal score for this Mac (chart read 10 Oct 2026). Pages checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, Late 2015) - Technical Specification; Apple Support (UK) — Identify your iMac model; Apple Newsroom (UK) — Apple Updates iMac Family with Stunning New Retina Displays, read 9 Oct 2026.