Jakob's Law
People spend most of their time on other products, so they expect yours to work the way those do.
Definition
Jakob Nielsen's observation that users build expectations from the cumulative experience of every other interface they use. Meeting those expectations is nearly free; violating them charges the user a learning cost that your product has to be worth.
Craft convention. True because the industry converged on it. Breaking it costs familiarity, not correctness.
On this page
Why it holds anyway
Conventions are a shared cache. A logo at the top left that returns home, a cart icon at the top right, an underlined blue link, a hamburger on mobile: none of these are intrinsically correct, but they are known. Reusing them means the user spends their attention on your content instead of on your chrome.
The cost of breaking a convention is not the moment of confusion. It is the ongoing tax on every subsequent interaction until the new model is learned, multiplied by the users who leave before learning it.
Conventions worth keeping unless you have a strong reason
- Logo top left, linking to the home page.
- Primary navigation across the top on desktop, bottom on mobile apps.
- Search represented by a magnifier, positioned top right or in a prominent bar.
- Cart or account in the top right corner.
- Form labels above inputs, errors below the field they belong to.
- Primary action on the right in a horizontal button pair on the web, following platform order in native dialogs.
- Underline or clear color difference for inline links.
When to break it
Break a convention when the convention is genuinely bad for your task and you can afford to teach the new model. Professional tools do this constantly: Figma's canvas, a code editor's command palette and a DAW's timeline all violate general web conventions and are correct to.
The test is whether the user's task is frequent enough to amortise learning. A convention break in a tool someone uses eight hours a day is an investment. The same break on a checkout page someone visits twice a year is a leak.
In practice
Do
- Be conventional in navigation, forms and checkout. Be distinctive in content, voice and the parts that are genuinely your product.
- Test convention breaks with people who have never seen your product, not with your team.
- Adopt platform conventions for platform surfaces: date pickers, share sheets, back behaviour.
Do not
- Rename standard actions for brand voice. 'Add to bag' is fine. 'Acquire' is not.
- Invent a new scroll behaviour on a content page.
- Confuse visual distinctiveness with structural novelty. You can look unlike everyone else while behaving like everyone else.
In practice
Ecommerce cart placement
RetailMoving the cart out of the top right corner reliably produces support tickets and abandoned sessions, even when the new placement is objectively more visible. The expectation is stronger than the salience.
Command palettes
Developer toolsThe Cmd+K palette started as a convention break in code editors, spread across professional tools, and is now itself a convention for that class of product. Conventions are local to a category, not global.
Sources
Where a source establishes something narrower than the popular reading of it, the note says so.
Jakob's Law of Internet User Experience
J. Nielsen, Nielsen Norman Group, 2000
Originally stated in the context of web design conventions.
Criteria for optimal web design (designing for usability)
M. Bernard, Software Usability Research Laboratory, 2003
Empirical work on where users expect common web elements to be located.
Continue from here
Each link says what the connection is, so you can tell a principle from an alternative from a thing people mix this up with.
Applies when you are designing
Why this works
The reasoning this entry rests on.
- Status Quo BiasCognitive bias
- Mental ModelsMental model
Convention is valuable because it matches a model people already hold.
- Mere Exposure EffectPsychology
Applied through
Where this shows up as a concrete interface decision.
- Design Brief to Wireframe DirectionAI workflow
- Design System AdoptionDesign system
- NavigationPattern
- Competitive AnalysisResearch method
Check your work
Review passes that test whether this was done properly.
- Ecommerce ChecklistChecklist
- Web UX ChecklistChecklist
Short definition
The one-paragraph version, for when that is all you need.
- Design PatternTerm
- Mental ModelTerm
Related concept
Connected closely enough to change how you apply this.
- Consistency and StandardsHeuristic
- Match Between System and the Real WorldHeuristic
- Recognition Over RecallHeuristic