Jakob's Law

Users spend most of their time on other sites. This means they prefer your site to work the same way as all the other sites they already know.

Overview

Jakob's Law captures a simple but often-resisted truth: users come to your product carrying mental models built from every other product they've used. When your interface works the way they expect from those experiences, they can focus on their task rather than on learning a new system. When it doesn't, every deviation is a moment of friction — small individually, but compounding across every interaction.

This doesn't mean all interfaces should look identical. It means convention should be the default, and departure from convention should be a deliberate choice made because it provides clear value that outweighs the learning cost. Most of the time, that bar is higher than designers assume — because the cost of a novel pattern is borne by the user, not the designer.

Takeaways

01
Align with established UX conventions wherever possible — users' mental models are built from thousands of hours on other products, and those models transfer directly to yours.
02
Deviating from convention requires a compelling reason: the benefit of the novel approach must clearly outweigh the cognitive cost of unlearning familiar patterns.
03
When changing a widely-used convention, allow a transition period — abrupt changes to familiar patterns cause disproportionate frustration even when the new pattern is objectively better.

How to Apply This

Use familiar patterns for familiar actions.
Search top-right or top-left. Logo top-left links home. Primary action top-right of a modal. These aren't creative constraints — they're patterns users have already internalised from hundreds of other products, and using them means zero learning cost for every new user.
Let conventions handle navigation.
Users have strong expectations about how navigation should behave. Hamburger menus, breadcrumbs, sticky headers — these patterns are known precisely because users have encountered them hundreds of times elsewhere. Novel navigation systems need to justify their cost explicitly.
When you must break convention, signal it clearly.
If your interface works differently from the norm, acknowledge it. Tooltips, onboarding flows, and clear UI affordances can bridge the gap between user expectations and your actual design — reducing the cost of the departure without abandoning it.

Common Misconception

Jakob's Law is not an argument against design innovation. It's an argument for understanding which conventions are load-bearing — deeply encoded in user mental models — before choosing to break them. New conventions can be established, but the cost of establishing them is real and should be factored into the decision.

Origin

Jakob's Law was coined by Jakob Nielsen, co-founder of the Nielsen Norman Group and one of the most influential researchers in usability. Nielsen formulated the law based on extensive research into user behaviour and mental models, observing that users consistently apply expectations built from previously used interfaces when encountering new ones. The insight has since become foundational in interaction design and is one of the most cited principles in usability engineering.

FAQ

What is Jakob's Law?: Jakob's Law states that users spend most of their time on interfaces other than yours, which means they arrive with pre-built mental models from those other products. Interfaces that match those expectations are perceived as easier to use — not because they are objectively simpler, but because they require no new learning.
Does Jakob's Law mean all websites should look the same?: No. It means that when you deviate from convention, you're asking users to invest cognitive effort in learning your novel pattern before they can focus on their actual task. That cost is real. The law says to make that tradeoff deliberately, not to avoid all differentiation — visual and brand differentiation can coexist with functional convention.
How do mental models relate to Jakob's Law?: A mental model is a user's internal understanding of how a system works, built from prior experience. Jakob's Law says that users import their mental models from other products into yours. When your interface matches those models, interaction feels intuitive. When it doesn't, users must update their models — a cognitively expensive process that most will resist.
When is it acceptable to break convention?: When the departure provides measurable, clear benefit that justifies the learning cost — and when you have the resources to help users make the transition. Platforms with large, engaged user bases can establish new conventions (as Apple and Google do regularly). For most products, breaking convention on core flows is a high-risk move that requires strong evidence to justify.