HD, which stands for High Definition, refers to the display resolution on Mac computers and devices. The higher the resolution, the sharper and more detailed the image quality is on a screen.
Quick Answer
On Mac computers and devices, HD resolutions typically start at 1280 x 720 pixels (720p) and go up to 3840 x 2160 pixels (4K). The most common HD resolutions you’ll see are:
- 1280 x 720 pixels (720p)
- 1920 x 1080 pixels (1080p)
- 2560 x 1440 pixels (1440p)
- 3840 x 2160 pixels (4K)
Higher resolutions like 5K and 8K are also considered HD, but less common on Macs currently. The higher the resolution (more pixels), the sharper and more detailed the image.
What is Display Resolution?
Display resolution refers to the number of pixels (individual dots) contained on a display. It’s expressed as the number of pixels horizontally x the number vertically. For example, a resolution of 1920 x 1080 means there are 1920 pixels across horizontally and 1080 vertically, equaling around 2 million total pixels.
The more pixels on a display, the sharper and more detailed the image can be. Higher resolutions allow you to see more fine details and textures, as well as fit more content on the screen without things looking pixelated or fuzzy.
Common Display Resolutions
Here are some common display resolutions you’ll see from low to high:
- 720p (1280 x 720) – The minimum for HD. Called 720p because it’s 720 horizontal lines high.
- 1080p (1920 x 1080) – The most popular HD resolution. Also called Full HD (FHD).
- 1440p (2560 x 1440) – Mid-way between 1080p and 4K. Also called Quad HD (QHD).
- 4K (3840 x 2160) – Called 4K because it’s approximately 4000 pixels wide. Also known as Ultra HD (UHD).
- 5K (5120 x 2880) – Primarily found on 27-inch iMacs currently.
- 8K (7680 x 4320) – The highest consumer resolution. But rarely found currently.
There are also some common non-HD resolutions below 720p like:
- 1024 x 768
- 1280 x 800
- 1440 x 900
But in general, most modern Macs and displays are at least 720p HD or higher.
Mac Display Resolutions
Here are some of the common native resolutions you’ll find on various Mac models:
MacBook Air & MacBook Pro
- 13-inch: 2560 x 1600 (non-Retina), 2560 x 1600 (Retina)
- 15-inch: 2880 x 1800 (Retina)
- 16-inch: 3072 x 1920 (Retina)
iMac
- 21.5-inch: 1920 x 1080 (non-Retina), 4096 x 2304 (Retina 4K)
- 27-inch: 2560 x 1440 (non-Retina), 5120 x 2880 (Retina 5K)
iMac Pro
- 27-inch: 5120 x 2880 (Retina 5K)
Mac Pro
- Up to 4096 x 2304 (Retina 4K)
- Up to 6016 x 3384 (Retina 6K)
Mac Mini
- Up to 4096 x 2304 (Retina 4K)
MacBook
- 12-inch: 2304 x 1440
As you can see, almost all modern Macs feature display resolutions of at least 1920 x 1080 (Full HD) or higher. Apple began transitioning to Retina displays with resolutions of 2560 x 1600 and above starting in 2012.
External Display Resolutions
When connecting most modern Macs to an external display or TV, you can output video at the following resolutions depending on the Mac model:
- Up to 3840 x 2160 (4K UHD)
- Up to 4096 x 2304 (4K)
- Up to 5120 × 2880 (5K)
- Up to 6016 x 3384 (6K)
The latest Macs can typically support up to two external displays at up to 4K resolution each. Some models like the Mac Pro support higher 5K – 8K resolutions on up to four or six displays when using multiple GPUs.
Using HDMI vs DisplayPort vs Thunderbolt
The type of connection you use between your Mac and display also affects the maximum resolutions. Here are the typical maximum resolutions for different port types:
| Connection Type | Max Resolution |
|---|---|
| HDMI | 3840 x 2160 (4K) |
| Mini DisplayPort | 3840 x 2160 (4K) |
| Thunderbolt 1/2 | 3840 x 2160 (4K) |
| Thunderbolt 3 (USB-C) | 5120 x 2880 (5K) or higher |
Thunderbolt 3 connections support the highest resolutions and bandwidth, allowing for multiple high-res external displays on recent Macs.
Resolution vs Pixel Density
Two displays with the same resolution may not exactly look the same. This is because pixel density also affects image sharpness and clarity.
Pixel density is measured in pixels per inch (PPI) or pixels per centimeter (PPCM). It essentially tells you how tightly the pixels are packed together on a display.
A lower pixel density means the pixels are more spread out, making things look more pixelated and less sharp. A higher pixel density means the pixels are more densely packed together, allowing for sharper-looking text and images.
Apple’s Retina displays typically have PPI of 220 or higher. This results in extremely sharp image quality where individual pixels become indistinguishable at normal viewing distances.
Scaling Resolutions for Proper Pixel Density
To achieve optimal pixel density on displays of varying sizes, MacOS and iOS use scaling resolutions. This means rendering UI elements and content at resolutions higher or lower than the display’s native resolution, then scaling them down or up.
For example, the 12.9-inch iPad Pro has a native display resolution of 2732 x 2048 pixels. But iOS renders content at 2048 x 2732 then scales it down for proper pixel density. This results in sharp, crisp text and images optimized for that size screen.
MacOS does similar resolution scaling based on a display’s pixel density to optimize the viewing experience. You can adjust scaling settings in System Preferences > Displays on a Mac.
HD vs Retina vs 4K Displays
With all the different resolutions and PPI measurements, what do terms like HD and Retina really mean on Macs? Here’s an overview:
HD
HD refers to any display or resolution with at least 720 vertical lines of resolution. So 1280 x 720 pixels (720p) is considered the minimum for HD.
Retina
Retina is Apple’s marketing term for displays with ~220 PPI or higher. At normal viewing distances, individual pixels become indistinguishable resulting in “Retina” sharpness and clarity.
4K
4K refers to displays with a horizontal resolution of around 4000 pixels. The most common 4K resolution is 3840 x 2160 pixels (UHD).
Although Retina and 4K aim for visual sharpness, Retina focuses on pixel density while 4K focuses on total resolution count. A Retina display may not be 4K, and a 4K display may not qualify as Retina depending on its size and viewing distance.
HD vs Standard Definition
HD resolutions offer major visual improvements over standard definition displays of the past. Here’s a quick comparison between standard definition and high definition:
| Resolution | Definition | Use Cases |
|---|---|---|
| 1280 x 720 and up | HD (High Definition) | Modern TVs, displays, mobile devices |
| 640 x 480 (VGA) | SD (Standard Definition) | Older computers, TVs |
| 320 x 240 | Low Resolution | Very old displays, video conferencing |
As you can see, HD represents a major jump up from the SD resolutions of the past. The 1280 x 720 pixel count provides over 6x as many pixels as a 640 x 480 display resulting in a dramatically sharper, more detailed image.
720p HD first became popular in the late 2000s as LCD TVs and displaysreplaced earlier CRT and plasma technologies. Since then, TV and computer resolutions have continued advancing to 4K, 5K, 8K and beyond.
How Video Content Scales on Different Resolutions
The resolution of video content also matters in determining image quality. Here’s how different video resolutions typically scale on various display resolutions:
| Video Resolution | 720p Display | 1080p Display | 4K Display |
|---|---|---|---|
| 720p | 1:1 Pixel Mapping | Upscaled | Upscaled |
| 1080p | Downscaled | 1:1 Pixel Mapping | Upscaled |
| 4K | Downscaled | Downscaled | 1:1 Pixel Mapping |
| 8K | Downscaled | Downscaled | Downscaled |
As you can see, the best image quality results when the video resolution matches the display resolution. Otherwise the video will be scaled up or down as needed. Upscaling leads to a softening of image quality while downscaling can result in lost details.
Optimizing Video Resolution
To get the maximum sharpness and detail from your display, try to watch video content that matches your display’s native resolution. For example, 1080p video on a 1080p screen or 4K video on a 4K screen.
Lower resolution video like 720p will still look decent, but won’t be quite as detailed. And very high resolution 8K video will exceed what most displays can even show currently.
How Display Resolution Affects Gaming
Display resolution also impacts gaming graphics and performance. Here are some key considerations:
- Higher resolution displays allow games to render at higher graphical settings and resolutions for improved visuals.
- Gaming at resolutions above 1080p such as 1440p or 4K requires more powerful GPU hardware for smooth high frame rates.
- Competitive online games often favor lower resolutions like 1080p for maximum high FPS gameplay.
- Higher resolution displays allow you to better appreciate detailed game graphics and environments for immersive single-player gaming.
- Console games are usually optimized for common HD and 4K TV resolutions like 1080p and 4K.
Ultimately, choose a display resolution appropriate for the types of games you play and hardware you use. Faster GPUs allow you to better leverage higher resolutions like 1440p or 4K for gaming.
Improving Display Resolution on a Mac
If your Mac’s display resolution seems too low or pixelated, here are some tips to improve it:
- Adjust resolution scaling settings in System Preferences > Displays to make text/icons larger.
- Upgrade your Mac to a model with a higher-res Retina display.
- Use an external display that has higher native resolution than your Mac’s built-in display.
- Choose “More Space” or “Scaled” resolution modes for higher effective resolutions.
- Close unneeded apps and windows to maximize screen space for your main workflow.
- Zoom in on documents and apps when you need larger, more readable elements.
Finally, keep in mind that increasing resolution alone doesn’t guarantee image quality. Factors like display size, viewing distance, and pixel density also affect sharpness and clarity.
Conclusion
In summary, HD, Retina, and 4K refer to displays with progressively higher resolutions and pixel densities for sharper, clearer visuals. An HD display provides a base level of 720p resolution and image quality. Retina improves that to 220+ PPI for indistinguishable pixels. And 4K boosts total resolution to around 4000 pixels wide.
Higher resolutions enable you to view and edit more content clearly. And they make images, video, and games look more detailed and lifelike. So when choosing a Mac or display, aim for the highest resolution that fits your visual needs and budget.
