HomeVector IconsWhich Icons Are Easier to Identify Quickly: Solid or Outline?

Which Icons Are Easier to Identify Quickly: Solid or Outline?

Icons are now an essential component of every website or application’s user interface (UI) design. The use of icons can be used to improve the visual appeal of any mobile app or website while also clearly communicating to users the essence and purpose of any given product or action. The primary goal of using an icon on a website or mobile application is to direct users to the appropriate location. Because of this, UI designers carefully consider both the overall feel that each icon conveys as well as its design and appearance. For example, every web designer must take the user experience into account when deciding whether to use solid or outline icons.

Research [based on the research study “Filled-in vs. Outline Icons: The Impact of Icon Style on Usability”] has shown that the main difference between the two icon styles is not just a matter of personal preference. It also shows that choosing the best icon for a website or application is not just a matter of weighing ease of recognition against other factors. When using an outline or solid icons, it is equally important to take the user’s ability to quickly recognize the icons, navigate an app or website, or choose the appropriate option into account.

Icons: Solid or Outline

Functions of icons: 

Regarding the usefulness of solid or outline icons, web designers may have varying opinions. Since empty icons are created of outlines instead of solid colors, many web designers think they are more difficult to recognize. But it’s also true that outline icons give users a sense of comfort. Therefore, it is crucial to take both the icons’ purposes and appearance into account. Whether an icon is correctly recognizable or not also depends on its form, color, and functions.

One particular kind of icon is the functional icon. These symbols are frequently seen in public locations such as hotels, shopping centers, airports, and train stations. Visitors are given directions using these icons. Among the most frequently used UI design components are icons. In addition to serving a number of other purposes, these elements can be used to carry out various kinds of actions or to provide descriptions.

The text and icons work together to communicate a message. When Free Vector icons from a list are removed, it is difficult to tell what data is still present. Users may find it difficult to concentrate on the options offered on a line if there are no icons present, which may even lead to visual confusion.

Characteristic Cues:

Users recognize icons by using characteristic cues. The icon loses its ability to be recognized if distinguishing cues are obscured or absent. An example of a characteristic cue is the tail of a remark bubble icon. It’s just a circle without it, that’s all. A lock icon’s identifying feature is its keyhole. It makes the icon appear more like a bag without it. A cog icon’s defining feature is its set of teeth. It appears to be a doughnut in its absence.

Over a third of all failures involved the lock icon, which was used in the study but did not have a keyhole. Without it, the icon would resemble a bag, purse, or even a pot, so the keyhole is a crucial characteristic cue. Users rely on these characteristic cues to recognize icons. When using icons, make sure they include all of the distinguishing features that users require to identify them. Consider adding extra characterizing cues to an icon if it could be mistaken for another object.

When Outline Icons Perform Quicker:

The cues must also be relevant or simple to notice in addition to having characteristic cues. In outline styles rather than solid styles, certain icons’ characteristic cues can occasionally stand out more. According to the study, the comment bubble, trash can, and key icons were the three that people could recognize more quickly in outline style. On the outside edges of the shape, these icons have obliquely visible identifying cues.

This makes those cues more obvious when written in an outline style. The comment bubble tail is more noticeable as outlines rather than solids because it is easier to see them. With a solid design, it is difficult to see the trash can lid; however, with an outline, it is easier to see. The jagged edges are easier to see in an outline style but the key teeth are subtle.

Use an outline style when a shape’s edges include a modest distinctive signal for an icon. As a result, cues become more noticeable and are recognized more quickly. It’s essential to follow a recognizable style while selecting all free vector icons. Try to pick a group of icons with conspicuous characteristic signals with stronger edges that point outward rather than combining solid and outline styles.

For example, you can tell the difference when you contrast the comment, trash can, and key icons with those that have more obvious indications. The more obvious indications stand out and are simpler to pick up on.

When Solid Icons Perform Quicker:

Most icons are representations of actual, tangible items. These things are substantial however, they just appear to be silhouetted. Icons being seen as outlines is not a true picture of how most people view things. It is easier to distinguish solid icons because of this. The users may still identify outline icons in spite of this. But if the shape outlines of the icon are too close together, it will take them more time to do so.

The thumb, scissors, phone, and tools icons were considered to be easier to distinguish in a clear manner by the study’s participants. This is due to the fact that all of these icons’ outline styles have a small inner separation on their cues, which causes visual noise.

When representing things with a small inner gap, solid icons work well. The icon is easier to recognize because of the silhouette form’s straightforward shape.

When Icon Style Makes No Difference:

The study discovered icons that could be easily identified in either style. For example, the recognition times for the flag, shopping cart, and star icons were all comparable. This proves that the outline design of these icons didn’t impede user performance. The reason is because of their broad inner spacing, which lowers visual noise. The more noise that is produced by the inner space, which hinders identification, the narrower it is.

Style of Icon for Button Selection:

It’s usual practice to emphasize the active button on a tab bar with a solid icon, while the remaining buttons stay in outline form. However, this design approach is regressive and should be reversed. Users want faster identification times for alternatives they haven’t yet found, not for those they have already chosen.

The active button doesn’t need to have a solid icon. It matters more than the inactive buttons have sturdy icons. Instead of using a solid icon, highlight the active button by using an outline icon. It provides a more obvious style and color change that highlights the chosen button.


When constructing an icon, solid styling is favored over hollow/outline styling since it is believed that solid icons are more recognized than outline icons. This notion may be valid in some cases. For example, solid icons are more effective if you want a higher recognition rate, since these icons may boost the users’ ‘task speed’. However, if there are slight distinctive indicators, the ’empty symbols’ become immediately discernible. When choosing the proper style for different sorts of icons, keep the following considerations in mind.

  • Solid icons are easier to notice unless their indications are obscure and sufficiently prominent.
  • Use solid icons instead of the outline version of the inner gap is too small.
  • Outline icons with wide inner spacing are more identifiable.
  • Icons are made up of identifying cues that must be visible and noticeable.
  • If the solid version contains modest distinctive indications on the edges, use outline icons.
Bhushan Verma
Bhushan Verma
Optimizing life and web-pages. Either you will find me immersed in the world of images and vectors or watching cricket.
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