Tesler's law: complexity never disappears, it only moves
Florent Dabernat
September 8, 2026
3 min read
In this article
Every application holds a share of complexity that cannot be removed. The only real question: who carries it, the user or the designer? This is Tesler's law.
Formulated by interface pioneer Larry Tesler, this law of conservation of complexity states that a process has an incompressible complexity. You can move it, hide it, absorb it, but not make it vanish.
The principle
Filling an address, handling an exception, choosing an option: these steps carry an irreducible complexity. If the interface does not take it on, the user endures it. Simplifying is not erasing complexity, it is deciding where it goes.
What it implies in design
- Absorb it product-side. Good design handles complexity behind the scenes to offer simplicity up front.
- Smart defaults. Pre-filling, guessing, suggesting: all complexity the user does not have to carry.
- Invisible work pays off. What looks simple on screen often took a large design effort.
Complexity never disappears. The real work is deciding who bears it: you or the user.
The trade-off to own
The question is never "how to remove complexity" but "who should bear it". Every shortcut offered to the user is extra work owned on the design side. It is a choice, and it is the right one.
In practice
Spot, in each journey, where the complexity sits, then ask whether it is really the user's to carry. The designer's role is precisely to take on that load so the experience stays smooth on the surface.
Frequently asked questions
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What is Tesler's law?
- The law of conservation of complexity: every process has an irreducible complexity that can be moved but never removed.
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So you can never simplify?
- You can, but simplifying for the user means moving complexity toward the product and the designer. Perceived simplicity has a cost, owned behind the scenes.
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How do I apply this principle?
- Identify a journey's incompressible complexity, then absorb as much as possible on the interface side: defaults, automation, handling of edge cases.