Accessibility tools abound in most operating systems, all the better to help users with vision or hearing impairments. One of the best is the magnifier, which literally throws a digital magnifying glass on the screen to help those with eyesight problems combat what seems to be an ever-decreasing type size. Bifocals can only do so much.

Here's how to magnify things in every operating system you may use.

Windows 10 Magnifier

You can launch the built-in Windows Magnifier application by clicking the Windows key () > Settings > Ease of Access > Magnifier. Or search for "magnifier" using Cortana. The tiny app will launch, floating on your screen as a little magnifying glass.

There is a quicker shortcut, however: hit the Windows key and the plus sign ( and ) together, and the Magnifier box appears. Another tap of the will magnify things instantly; click and the minus sign () to zoom back out. Keep hitting and the or to zoom in and out repeatedly.

When you're looking at the on-screen interface pictured at right, click the or buttons to zoom in or out. Use the Views menu to switch between magnifying the whole screen, making only sections of the screen larger (Lens), or seeing a blown-up shot of wherever the cursor is below (Docked). Shortcut options: hit Ctrl+Alt+F for full screen, Ctrl+Alt+L for the Lens, Ctrl+Alt+D for the Docked magnifier, or Ctrl+Alt+Spacebar to temporarily see the whole display when you are zoomed in.

Ctrl+Alt+I will invert colors on whatever you have magnified—or not magnified; colors can still be inverted to look like a film negative, even if nothing is magnified.

Click the gear icon () to access magnifier tool options—change how much you zoom in and out incrementally (25, 50, 100, etc., all the way up to 400 percent). Ctrl+Alt+R will quickly get into the resize options. In the Control Panel, you can set magnifier to start with Windows 10 so it's always available.

The best way to use Magnifier for most people is likely the floating Lens option. With that turned on, click the to see options like inverting all the colors in the lens area, or changing the lens size—the taller and wider it is, the more of the screen it will take up.

When you're done, click the dimmed, floating magnifying glass icon, and the X to exit; or hit +Esc. Magnifier will disappear until you need it again.

macOS Zoom

In macOS Sierra, the Zoom pane is in the Accessibility System Preferences—go to the Apple Menu () > System Preferences > Accessibility > Zoom.

This is the place to activate keyboard shortcuts, like Option+Command+[equal sign] to auto-zoom, Option+Command+[minus sign] to zoom out, and Option+Command+8 to toggle zoom on and off entirely. You can also set the Zoom style: zoom the whole screen or zoom in a window (Apple calls it Picture-in-Picture).

Activate modifier keys, like holding the Control Key (or the Option or Command keys; you pick) so you can drag two fingers up on a trackpad to zoom, or two fingers down to zoom out (or using a mouse wheel).

If you click the Options button in the Zoom preferences, the Magnification bar will show you the increments for enlargement options to follow the cursor as it moves, and the option to invert colors in the picture-in-picture view. Click the "Tiled along edge" option and the magnifier is docked to the side of the screen, similar to how Windows does it at the top of the screen. You can also set up the temporary zoom—hold down the Control+Option keys.

If you have a MacBook with the Touch Bar, you can zoom here too via the same Zoom accessibility settings; just enable "Touch Bar Zoom." Hold a single finger on the Touch Bar for it to appear on the screen, then hold the Command key and pinch two fingers open or closed along the Touch Bar to zoom in/out.

Android Magnification

On an Android device running Jelly Bean or later, go to Settings > Accessibility > Vision > Magnification Gestures (which could vary depending on the smartphone provider).

With that option turned on, you get easy screen magnification with a triple tap. The triple-tap won't work on the keyboard or navigation bar, so pick a somewhat blank area of the screen. When your screen is zoomed in, you can see an outline around it. Use two (or more) fingers to pan around and see different parts. You can move your two fingers apart to zoom in, or pinch to zoom back. Another triple tap and you're back to the regular screen.

If you only need to zoom for a moment, triple-tap but hold your finger down on the last tap. You can pan around with that one finger. Upon removing the finger tip from the glass, the screen pops back to normal.

Note that launching a new app while you're zoomed will deactivate the magnification, so you have to triple-tap again to re-zoom. And maybe worst of all, by turning this on, your single-taps on things—to launch apps, etc.—may be slightly delayed as the phone needs to hesitate a bit to see if your finger is going for the triple before it jumps the gun.

iOS Zoom vs. Magnifier

On iOS, there are several options, one called Zoom, the other called Magnifier. They are not the same thing. Each is found in Settings > General > Accessibility. Turn them on or off with a quick toggle of a switch.

Zoom is all about zooming in on things on your screen. To activate, you must perfect the triple/double-tap—that's tapping three fingers simultaneously, twice, on the screen.

If it's on, there is always a little zoom controller icon on your screen (unless you turn off "show controller"); when the zoom windows is active, the controller is like a little on-screen joystick that lets you move the window around. Or you can tap and hold the tiny holder area on the bottom of the zoom window.

Magnifier is an entirely different beast. It's an actual digital magnifying glass for inspecting things in the real world. Turn it it, and tap the Home button three times. It automatically starts the rear camera, but with a prominent slider bar at the bottom. For more, check out this guide.