How does macOS scaling work, and what are HiDPI and LoDPI?

macOS scaling lets you choose how large text and windows appear while still using the display’s physical pixels. HiDPI and LoDPI describe how much detail macOS renders for that desktop size. Understanding the difference helps you choose comfortable scaling without confusing desktop space with image sharpness.

A smaller desktop size makes things larger. HiDPI gives macOS more pixels to draw those things.

If you just want to adjust your screen, start with making text larger or adding intermediate HiDPI resolutions. Read on to understand why those choices work.

Why are there several different resolutions?

A display’s resolution can mean different things depending on what you are measuring. Keep these three sizes separate:

The desktop uses coordinates called points. A point is a logical unit, not necessarily one physical pixel; positions can include fractions of a point. A desktop described as 2560 × 1440 therefore does not tell you, on its own, how many pixels were used to render it.

There is also the output signal sent over the cable. In the examples below, the monitor receives its native resolution and does not resize the image again. Other signal timings, monitor processing, mirroring or streaming can introduce another scaling step. Display Information helps you distinguish the active desktop mode from connection information.

What changes between LoDPI and HiDPI?

LoDPI and HiDPI are the ordinary and high-resolution rendering modes in BetterDisplay’s mode lists. At the same logical desktop size, LoDPI uses one rendering pixel per point along each axis; HiDPI uses two.

HiDPI gives text, curves and suitable high-resolution images more detail without changing the logical desktop size. At that same size on the same screen, switching to HiDPI is not inherently a request for larger text.

Apple’s high-resolution explanation describes this separation of points and pixels. Apps can draw text and vector shapes at the higher resolution; a low-resolution bitmap does not gain real detail merely by being enlarged.

How can a 4K screen show a 5K rendered desktop?

Consider a 3840 × 2160 monitor. Two useful HiDPI desktop sizes illustrate the difference:

• 1920 × 1080 HiDPI renders at 3840 × 2160. The rendered pixels can map directly to the panel’s pixels, giving you a larger interface without a final resize.
• 2560 × 1440 HiDPI renders at 5120 × 2880. macOS then reduces that image to 3840 × 2160, giving you more desktop space and smaller interface elements.

The second choice is commonly called fractional scaling: the rendered image and physical pixel grid do not match one for one. The backing scale remains 2×; it is the final resize that introduces a fractional relationship. Apple’s backing-scale documentation distinguishes that rendering scale from physical resolution.

This does not require the monitor to accept a 5K signal. The 5K image is the rendering surface; the output can remain 4K. Likewise, a screenshot or recording showing 5K dimensions is not proof of a 5K signal over the cable.

2560 × 1440 HiDPI is a useful starting point for many 27-inch or 32-inch 4K displays, but the right size depends on your eyesight, viewing distance and work. It is not a universal optimum.

Is HiDPI useful on a QHD or other lower-density display?

It can be, especially when the native desktop makes text too small. On a 2560 × 1440 QHD panel, a 1920 × 1080 HiDPI desktop renders at 3840 × 2160 and is reduced to the panel’s grid. The interface becomes larger while retaining more desktop space than a 1280 × 720 HiDPI mode would provide.

A 24-inch QHD screen packs the same pixels into a smaller area than a 27-inch QHD screen. That higher density can make intermediate HiDPI scaling particularly useful, although your preferred size remains a personal choice.

There is a different tradeoff if you keep 2560 × 1440 as the logical desktop on that QHD panel. HiDPI renders at 5120 × 2880, then reduces the image to 2560 × 1440. This is supersampling: drawing at a higher resolution before reducing the result.

Supersampling can change the smoothness of text and edges. Some people prefer the result; others find it softer than native LoDPI. It cannot reveal all the detail that the same rendered desktop would show on a physical 5K panel. Higher-resolution captures may still be useful, provided the capture tool retains those pixels.

More rendering pixels can improve the image you start with. The panel’s physical pixels still set the limit on the detail you can see.

If the result remains poor, check text clarity after enabling HiDPI. Monitor sharpening, picture modes and chroma subsampling can matter alongside scaling.

Why can text look different from Windows or Linux?

Operating systems and applications make different choices about font shapes and smoothing. One relevant difference is subpixel antialiasing, which uses an LCD’s red, green and blue subpixels to adjust letter edges. It can improve perceived horizontal text detail on suitable panels; it does not literally triple the display’s full-color resolution.

macOS stopped using its system subpixel antialiasing in macOS Mojave. It still smooths text using grayscale antialiasing. WebKit’s engineering record documents that change. On a low-density display, the difference can be more noticeable because there are fewer physical pixels available to describe each letter.

Subpixel treatment depends on the panel’s subpixel layout and final pixel alignment. Resizing the completed image can disrupt that alignment. This explains a technical difficulty with combining subpixel text and fractional scaling; it does not establish Apple’s motives for removing the feature.

Neither platform is simply “vector-based” or “bitmap-based”: macOS also draws vector text and shapes before composing the final pixel image. Results on Windows and Linux likewise depend on the application, font settings and scaling path. Choose the result that is easiest for you to read, rather than expecting one rendering method to look identical everywhere.

Does HiDPI cost more performance?

At the same logical size, a 2× HiDPI image contains four times as many pixels as LoDPI. An individual image buffer with the same pixel format consequently needs four times the storage. The total memory use and speed of the desktop depend on much more than that one buffer.

More rendering pixels and a final resize can increase graphics work. The effect varies with your Mac, applications, desktop size and capture workload; four times the pixels does not mean every app runs four times slower. Apple also notes that scaled resolutions may affect performance.

If a 3D app or recorder struggles, compare a smaller HiDPI desktop or adjust the app’s own rendering resolution. See HiDPI performance troubleshooting for practical comparisons.

What do flexible scaling and custom resolutions add?

BetterDisplay’s flexible scaling generates a fine-grained range of scaled desktop sizes matching the display’s aspect ratio. Instead of accepting a few widely spaced choices, you can use the resolution slider to find a size between them.

Custom scaled resolutions let you request specific desktop dimensions instead. Enter the intended logical size; BetterDisplay prepares HiDPI and LoDPI variants where possible. You do not need to double the dimensions yourself to request HiDPI.

Both use macOS’s native scaling path on eligible displays. They add choices; they do not introduce a separate font renderer or sharpen an identical mode that was already available. For setup, Apply and activation requirements, licensing and platform differences, follow System Configuration and Flexible Scaling or the shorter add HiDPI resolutions answer.

How should I choose a mode?

1. Choose a logical desktop size that makes text comfortable at your normal viewing distance. Smaller dimensions make the interface larger; larger dimensions fit more content.
2. Check that the active mode is HiDPI when you want high-resolution rendering. The same width and height can exist in both classes.
3. Compare nearby sizes using ordinary text and your own applications. If exact pixels matter, also compare a mode whose rendering dimensions match the panel.
4. Check performance and any needed refresh rate or HDR support before settling on the mode.

The best choice balances readable text, useful desktop space and reliable performance on your setup.

Put these concepts into practice with the fully scalable HiDPI desktop tutorial.