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iMac (Retina 4K, 21.5-inch, 2019) vs MacBook Air (Retina, 13-inch, 2018)

iMac (Retina 4K, 21.5-inch, 2019)1MacBook Air (Retina, 13-inch, 2018)2

Quick look

Quick look: iMac against MacBook Air
FigureiMac1MacBook Air2
Price£1,2493launch price£1,1994launch price
ChipCore i33.6GHz quad-core IntelCore i51.6GHz dual-core Intel
CPU4-coreCPU2-coreCPU
Memory8GBmemory, base8GBmemory, base
Storage256GBstorage, base128GBstorage, base
Battery life Not available5No batteryUp to13 hrsvideo playback, claimed
Released19 March 20196Available online; Apple gave no in-store day7 November 20184ReleasedIn Apple Stores; orderable online from 30 October 2018.
Security updatesNot available7Security updates14 September 20268Security updates ended
Price
The iMac is £1,249 at launch, per Apple Newsroom (UK); the MacBook Air is £1,199 at launch, per Apple Newsroom (UK).
Kind of Mac
The iMac is an all-in-one; the MacBook Air is a laptop. The MacBook Air has a battery, whereas the iMac has none.

True to scale

iMac (Retina 4K, 21.5-inch, 2019) · 528 × 450 mm frontMacBook Air (Retina, 13-inch, 2018) · 304.1 × 212.4 mm footprint

An all-in-one and a laptop are different shapes, so they stand side by side rather than superposed: the front face of one and the footprint of the other, from Apple’s published dimensions, at one scale. Corner rounding is our drawing convention, not a measurement.

Specifications

Each figure is from the source marked by its Mac’s name unless it carries its own small number, which links to where that figure was read.

Body

Body: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple MacBook Air (Retina, 13-inch, 2018)
SpecificationiMac1MacBook Air2
Dimensions450 x 528 x 175 mm4.1–15.6 x 304.1 x 212.4 mm
Weight5.48 kg1.25 kg
ColoursNot available9Gold, Silver, Space Gray
PortsTwo Thunderbolt 3 (USB-C) ports, four USB-A ports, SDXC card slot, Gigabit Ethernet (RJ-45), 3.5 mm headphone jackTwo Thunderbolt 3 (USB-C) ports, 3.5 mm headphone jack
Thunderbolt ports22
Thunderbolt versionThunderbolt 3Thunderbolt 3
USB-A ports4No USB-A ports.10
HDMINo HDMI port.11No HDMI port.12
SD card slotYesNo SD card slot.12
Headphone jackYesYes
MagSafeNot available13No MagSafe port.12
KeyboardMagic KeyboardFull-size keyboard with LED-backlit keys
Touch IDNo Touch ID.11Yes

Display

Display: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple MacBook Air (Retina, 13-inch, 2018)
SpecificationiMac1MacBook Air2
Display size21.5 in13.3 in
Resolution4096 x 23042560 x 1600
Pixel densityNot available9227 ppi
Display typeRetina 4K displayRetina display
Brightness500 nitsNot available14
Wide colour (P3)YesNot available14

Chip and memory

Chip and memory: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple MacBook Air (Retina, 13-inch, 2018)
SpecificationiMac1MacBook Air2
Chip3.6GHz quad-core Intel Core i31.6GHz dual-core Intel Core i5
Apple siliconIntel processor, not Apple silicon.15Intel processor, not Apple silicon.10
CPU cores42
GraphicsRadeon Pro 555X with 2GB of GDDR5 memoryIntel UHD Graphics 617
Chip options3.6GHz quad-core Intel Core i3, 3.0GHz 6-core Intel Core i5, or 3.2GHz 6-core Intel Core i71.6GHz dual-core Intel Core i516
Memory (base)8GB8GB
Memory (maximum)32GB16GB
Memory options8GB, 16GB or 32GB8GB or 16GB
Memory upgradeable by userNo, as Apple documents17No, as Apple documents18
Storage (base)256GB128GB
Storage (maximum)1TB1.5TB
Storage options256GB SSD or 1TB Fusion Drive128GB, 256GB, 512GB or 1.5TB

Battery and power

Battery and power: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple MacBook Air (Retina, 13-inch, 2018)
SpecificationiMac1MacBook Air2
Battery capacityNot available550.3 Wh
Rated charge cyclesNot available51,000 cycles19
Video playback (claimed)Not available513 h
Wireless web (claimed)Not available512 h
Included power adapterNot available2030 W
Fast chargingNot available5No fast charging.12

Connectivity

Connectivity: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple MacBook Air (Retina, 13-inch, 2018)
SpecificationiMac1MacBook Air2
Wi-Fi802.11ac Wi-Fi802.11ac Wi-Fi
Bluetooth4.24.2
Ethernet10/100/1000BASE-T Gigabit Ethernet (RJ-45)No Ethernet port.12
External displays (base)22

Camera and audio

Camera and audio: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple MacBook Air (Retina, 13-inch, 2018)
SpecificationiMac1MacBook Air2
CameraFaceTime HD camera720p FaceTime HD camera
SpeakersStereo speakersStereo speakers
MicrophonesMicrophoneThree microphones

Platform

Platform: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple MacBook Air (Retina, 13-inch, 2018)
SpecificationiMac1MacBook Air2
Shipped withmacOS Mojave21macOS Mojave22
Newest macOSmacOS Sequoia23macOS Sonoma24
Model identifieriMac19,223MacBookAir8,124
Model year20192018

Sources

  1. Apple Support (UK) — iMac (Retina 4K, 21.5-inch, 2019) - Technical Specifications · Default for iMac · Apple’s figure · read 15 Sep 2026

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  2. Apple Support (UK) — MacBook Air (Retina, 13-inch, 2018) - Technical Specifications · Default for MacBook Air · Apple’s figure · read 15 Sep 2026

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  3. Apple Newsroom (UK) — iMac gets a 2x performance boost · Apple’s figure · read 15 Sep 2026

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  4. Apple Newsroom (UK) — All-new MacBook Air takes flight · Apple’s figure · read 15 Sep 2026

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  5. Doesn’t apply: no battery

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  6. Apple Newsroom (UK) — iMac gets a 2x performance boost · Apple’s figure · read 22 Sep 2026

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  7. Security updates: no end date published. Checked: endoflife.date. Read 22 Sep 2026

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

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  9. Not published by Apple. Pages checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, 2019) - Technical Specifications; Apple Support (UK) — Identify your iMac model; Apple Newsroom (UK) — iMac gets a 2x performance boost. Read 9 Oct 2026

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  10. MacBook Air (Retina, 13-inch, 2018): No USB-A ports. Intel processor, not Apple silicon. Checked: Apple Support (UK) — MacBook Air (Retina, 13-inch, 2018) - Technical Specifications. Read 15 Sep 2026

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  11. iMac (Retina 4K, 21.5-inch, 2019): No HDMI port. No Touch ID. Checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, 2019) - Technical Specifications. Read 9 Oct 2026

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  12. MacBook Air (Retina, 13-inch, 2018): No HDMI port. No SD card slot. No MagSafe port. No fast charging. No Ethernet port. Checked: Apple Support (UK) — MacBook Air (Retina, 13-inch, 2018) - Technical Specifications. Read 9 Oct 2026

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  13. Doesn’t apply: MagSafe is a notebook charging port

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  14. Not published by Apple. Pages checked: Apple Support (UK) — MacBook Air (Retina, 13-inch, 2018) - Technical Specifications; Apple Support (UK) — Identify your MacBook Air model; Apple Newsroom (UK) — All-new MacBook Air takes flight. Read 9 Oct 2026

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  15. iMac (Retina 4K, 21.5-inch, 2019): Intel processor, not Apple silicon. Checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, 2019) - Technical Specifications. Read 15 Sep 2026

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  16. Apple Support (UK) — MacBook Air (Retina, 13-inch, 2018) - Technical Specifications · Apple’s figure · read 9 Oct 2026

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

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  18. Apple Support (UK) — MacBook Pro: how to remove or install memory · Apple’s figure · read 18 Oct 2026

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  19. Apple Support (UK) — Determine battery cycle count for Mac laptops · Apple’s figure · read 15 Oct 2026

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  20. Doesn’t apply: internal power supply, no power adapter in the box

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  21. Apple Newsroom (UK) — iMac gets a 2x performance boost · Apple’s figure · read 9 Oct 2026

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  22. Apple Newsroom (UK) — All-new MacBook Air takes flight · Apple’s figure · read 9 Oct 2026

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

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  24. Apple Support (UK) — Identify your MacBook Air model · Apple’s figure · read 15 Sep 2026

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Not published by Apple

iMac. Apple doesn’t publish for this Mac: 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, 2019) - Technical Specifications; Apple Support (UK) — Identify your iMac model; Apple Newsroom (UK) — iMac gets a 2x performance boost, read 9 Oct 2026.

MacBook Air. Apple doesn’t publish for this Mac: refresh rate, nano-texture option, GPU cores, storage upgradeable by user. Geekbench 7: the Mac chart has no entry for this Mac, so no figures are shown (chart read 10 Oct 2026). Pages checked: Apple Support (UK) — MacBook Air (Retina, 13-inch, 2018) - Technical Specifications; Apple Support (UK) — Identify your MacBook Air model; Apple Newsroom (UK) — All-new MacBook Air takes flight, read 9 Oct 2026.

If you own one of them

Whether to move is a different question from which is better. Each Mac has a page on it: what its successor changes (the newest Mac in its line where Apple sells one, otherwise the Mac this site treats as its replacement, which can be in another line), what it fetches and whether it still gets updates. Should I upgrade my iMac (Retina 4K, 21.5-inch, 2019)? · Should I upgrade my MacBook Air (Retina, 13-inch, 2018)?

The pairs a buyer of either Mac would also weigh. Any two Macs in the catalogue can be compared from the chooser.