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iMac (Retina 4K, 21.5-inch, 2017) - Technical Specifications


  • Retina 4K display

  • 21.5-inch (diagonal) Retina 4K display

  • 4096-by-2304 resolution with support for one billion colors

  • 500 nits brightness

  • Wide color (P3)


  • 3.0GHz

    • 3.0GHz quad‑core Intel Core i5 (Turbo Boost up to 3.5GHz)

    • Configurable to 3.6GHz quad-core Intel Core i7 (Turbo Boost up to 4.2GHz)

  • 3.4GHz

    • 3.4GHz quad-core Intel Core i5 (Turbo Boost up to 3.8GHz)

    • Configurable to 3.6GHz quad-core Intel Core i7 (Turbo Boost up to 4.2GHz)


  • 3.0GHz

    • 8GB of 2400MHz DDR4 memory

    • Configurable to 16GB

  • 3.4GHz

    • 8GB of 2400MHz DDR4 memory

    • Configurable to 16GB or 32GB


  • 3.0GHz

    • 1TB (5400-rpm) hard drive

    • Configurable to 1TB Fusion Drive or 256GB or 512GB SSD

  • 3.4GHz

    • 1TB Fusion Drive

    • Configurable to 256GB, 512GB, or 1TB SSD


  • 3.0GHz

    • Radeon Pro 555 with 2GB of VRAM

  • 3.4GHz

    • Radeon Pro 560 with 4GB of VRAM

Video Support and Camera

  • FaceTime HD camera

  • Simultaneously supports full native resolution on the built-in display at millions of colors (21.5-inch) or 1 billion colors (21.5-inch 4K) and:

    • One 5120‑by‑2880 (5K) external display at 60Hz with support for 1 billion colors, or

    • Two 3840-by-2160 (4K UHD) external displays at 60Hz with support for 1 billion colors, or

    • Two 4096‑by‑2304 (4K) external displays at 60Hz with support for millions of colors

  • Thunderbolt 3 digital video output

  • Native DisplayPort output over USB‑C

  • Thunderbolt 2, HDMI, DVI, and VGA output supported using adapters (sold separately)


  • Stereo speakers

  • Microphone

  • 3.5 mm headphone jack

    • Support for Apple iPhone headset with microphone

Connections and Expansion

  • 3.5 mm headphone jack

  • SDXC card slot

  • Four USB 3 ports (compatible with USB 2)

  • Two Thunderbolt 3 (USB-C) ports with support for:

    • DisplayPort

    • Thunderbolt (up to 40 Gbps)

    • USB 3.1 Gen 2 (up to 10 Gbps)

    • Thunderbolt 2, HDMI, DVI, and VGA supported using adapters (sold separately)

  • 10/100/1000BASE-T Gigabit Ethernet (RJ-45 connector)

  • Kensington lock slot


  • Magic Keyboard

    • Magic Keyboard comes standard with your iMac. It’s wireless and rechargeable (so you won’t be replacing batteries), with an ultracompact, edge-to-edge design that wastes no surface space. It has a stable scissor mechanism, optimized key travel, and a low profile that provide control and comfort. And it pairs immediately with your iMac right out of the box.

  • Magic Keyboard with Numeric Keypad

    • You get all the functionality of Magic Keyboard, with an extended layout that makes it even easier to work and play. The new Magic Keyboard with Numeric Keypad includes document navigation controls — page up, page down, home, and end — and full-size arrow keys that are perfect for navigating pro apps, moving through spreadsheets, and playing games.

  • Magic Mouse 2

    • Magic Mouse 2 comes standard with your iMac. The design of Magic Mouse 2 lets it glide smoothly across your desk. And since it supports Multi-Touch, you can use simple gestures on its surface to do things such as swipe between web pages and scroll through documents.

  • Magic Trackpad 2

    • If you prefer using a trackpad, Magic Trackpad 2 gives you the full range of Multi-Touch gestures and introduces Force Touch to the desktop. Sensors underneath the trackpad surface detect subtle differences in the amount of pressure you apply, bringing more functionality to your fingertips and enabling a deeper connection to your content. This design, along with a low profile, makes it extremely comfortable to use.


  • Wi-Fi

    • 802.11ac Wi-Fi wireless networking

    • IEEE 802.11a/b/g/n compatible

  • Bluetooth

    • Bluetooth 4.2 wireless technology

Size and Weight

  • Height: 17.7 inches (45.0 cm)

  • Width: 20.8 inches (52.8 cm)

  • Stand depth: 6.9 inches (17.5 cm)

  • Weight: 12.5 pounds (5.66 kg)2

Electrical and Operating Requirements

  • Line voltage: 100–240V AC

  • Frequency: 50Hz to 60Hz, single phase

  • Operating temperature: 50° to 95° F (10° to 35° C)

  • Relative humidity: 5% to 95% noncondensing

  • Operating altitude: tested up to 10,000 feet

In the Box

  • 21.5‑inch iMac with Retina 4K display

  • Magic Keyboard

  • Magic Mouse 2

  • Power cord

  • Lightning to USB Cable

Operating System


macOS is the operating system that powers everything you do on a Mac. macOS Mojave brings new features inspired by its most powerful users, but designed for everyone. So you can get more out of every click.

Learn more


Accessibility features help people with disabilities get the most out of their new iMac. With built-in support for vision, hearing, physical and motor skills, and learning and literacy, you can create and do amazing things.

Learn more

Features include:

  • VoiceOver

  • Zoom

  • Increase Contrast

  • Reduce Motion

  • Siri and Dictation

  • Switch Control

  • Closed Captions

  • Text to Speech

Built‑in Apps3

  • Photos

  • iMovie

  • GarageBand

  • Pages

  • Numbers

  • Keynote

  • Siri

  • Safari

  • Mail

  • FaceTime

  • Messages

  • Maps

  • News

  • Stocks

  • Home

  • Voice Memos

  • Notes

  • Calendar

  • Contacts

  • Reminders

  • Photo Booth

  • Preview

  • iTunes

  • Books

  • App Store

  • Time Machine

Configure to Order

Configure your iMac with these options.

Looking for an iMac you can mount on a wall or an adjustable arm? Choose an iMac with a Built-in VESA Mount Adapter.

  • 3.0GHz

    • Magic Trackpad 2

    • Magic Keyboard with Numeric Keypad

    • 3.6GHz quad-core Intel Core i7 upgrade

    • 16GB memory upgrade

    • 1TB Fusion Drive

    • 256GB or 512GB SSD

  • 3.4GHz

    • Magic Trackpad 2

    • Magic Keyboard with Numeric Keypad

    • 3.6GHz quad-core Intel Core i7 upgrade

    • 16GB or 32GB memory upgrade

    • 256GB, 512GB, or 1TB SSD

iMac and the Environment

Apple takes a complete product life cycle approach to determining our environmental impact. Learn more

iMac is designed with the following features to reduce its environmental impact:

  • Arsenic-free display glass

  • BFR-free

  • PVC-free4

  • Beryllium-free

  • Mercury-free LED-backlit display

  • Recyclable aluminum enclosure

  • Speaker enclosures made with 60 percent post‑consumer recycled plastic

  • Fan assembly made with 26 percent bio‑based plastic

  • Meets ENERGY STAR Version 6.1 requirements

  • Rated EPEAT Gold5

Apple and the Environment

Learn more about Apple’s dedication to reducing the environmental impact of our products and process. Or read our Product Environmental Reports for detailed information on the environmental performance of every Apple product.

Apple GiveBack

Letting go of your old Mac is easy with Apple GiveBack. If it’s in good shape, you can trade it in for Apple Store credit. If it’s not eligible for credit, we’ll recycle it responsibly at no cost to you. Good for you. Good for the planet.

See how it works

Acoustic Performance

Declared noise emission values in accordance with ECMA-109

Sound Power Level

L W A,m (B)

Sound Pressure Level

Operator Position

L p A,m (dB)


2.0 (K V =0.3)


Wireless web

2.0 (K V =0.3)


Hard drive seek

2.0 (K V =0.3)


  1. L W A,m is the mean A-weighted sound power level, rounded to the nearest 0.1 B.

  2. L p A,m is the mean A-weighted sound pressure level measured at operator position (rounded to the nearest 1 dB).

  3. 1 B (bel) = 10 dB (decibel)

  4. K v is the statistical adder for computing upper-limit of A-weighted sound power level.

  5. The quantity, L W A,c (formerly called L W Ad) may be computed from the sum of L W A,m and K v.

  6. The Wireless web test browses 25 popular websites.

  7. Configuration tested: 3.4GHz quad-core Intel Core i5 processor, 8GB memory, 1TB hard drive, Radeon Pro 560 Graphics.

  1. 1GB = 1 billion bytes and 1TB = 1 trillion bytes; actual formatted capacity less.

  2. Weight varies by configuration and manufacturing process.

  3. iMovie, GarageBand, Pages, Numbers, and Keynote are available on the Mac App Store. Downloading apps requires an Apple ID and a device that is compatible with the OS version required for each app.

  4. PVC-free AC power cord available in all regions except India and South Korea.

  5. iMac achieved a Gold rating from EPEAT in the U.S. and Canada.