Must a FAB be bottom right?

It's the default for right thumbs, though bottom centre exists; above all, never cover content.

Should iOS apps use FABs?

FABs aren't an iOS convention; prefer nav bar or tab bar buttons.

Floating Action Button

⚙️ Engineering & Technology By CampusDown Wiki Editorial Team Last updated October 27, 2026 Views 5

A floating action button is a round button that floats above content and stays put while scrolling, triggering one key action such as composing a new item.

Contents

1. Why a floating button
2. Common problems
3. Using it well
4. FAQ
5. References

Why a floating button

Material Design (Google, n.d.) created the FAB for a screen's most important action, like composing mail. One-handed thumbs reach the lower area easily (Bergstrom-Lehtovirta & Oulasvirta, 2014), hence bottom right, and larger closer targets are faster (Fitts's law; Fitts, 1954). Size it generously beyond touch target size minimums.

Common problems

Icon-only FABs rely on conventions (Norman, 1999); '+' is familiar but unusual icons are not, hence the labelled extended FAB. Hiding it on scroll frees space but creates a hidden affordance (Gaver, 1991). FABs also often cover the last list item or bottom navigation.

Using it well

Use one FAB per screen and pad list ends by its height. Float it above bottom tabs. Speed-dial items must also meet thumb sizes (Parhi et al., 2006). Give icons accessible names and check WCAG 2.2 (W3C, 2023) 2.5.8 and 2.4.11.

FAQ

Must a FAB be bottom right?: It's the default for right thumbs, though bottom centre exists; above all, never cover content.
Should iOS apps use FABs?: FABs aren't an iOS convention; prefer nav bar or tab bar buttons.

Sources reviewed: 2026-10-27

References

Google. (n.d.). Floating action button (FAB). Material Design 3. One primary action per screen.
Bergstrom-Lehtovirta, J., & Oulasvirta, A. (2014). Modeling the functional area of the thumb on mobile touchscreen surfaces. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (pp. 1991–2000). ACM. Thumb reach supports bottom placement.
Fitts, P. M. (1954). The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 47(6), 381–391. Larger, closer targets are faster.
Parhi, P., Karlson, A. K., & Bederson, B. B. (2006). Target size study for one-handed thumb use on small touchscreen devices. In Proceedings of MobileHCI 2006 (pp. 203–210). ACM. Thumb target sizes.
Norman, D. A. (1999). Affordance, conventions, and design. Interactions, 6(3), 38–43. Conventions and perceived affordance.
Gaver, W. W. (1991). Technology affordances. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (pp. 79–84). ACM. Hidden affordances.
World Wide Web Consortium. (2023). Web Content Accessibility Guidelines (WCAG) 2.2. Criteria 2.5.8 and 2.4.11.

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This article was last updated on October 27, 2026. It is based on widely recognized original works and textbooks; when citing it in a paper, please check the original sources listed in the references.