Why We Use the Fibonacci Scale in Our Product Design Squad
One of the most useful tools we’ve adopted in our product design squad is the Fibonacci scale for effort estimation. At first glance, it might seem like something that belongs more in a maths class than a design planning session. But once you start using it, it becomes a powerful way to drive clarity, alignment, and better planning across the team.
So what is it?
The Fibonacci scale is a sequence of numbers: 0, 1, 2, 3, 5, 8, 13, 21… You get the idea, each number is the sum of the two before it. In the context of product design, we use these numbers not as exact time estimates, but as a way to size up how complex or effort-heavy a task is.
Why it works (especially for design)
Design work is tricky to estimate. Some things are quick fixes, others are loaded with unknowns. The Fibonacci scale acknowledges this uncertainty. As the numbers get bigger, the gaps between them grow—because when things get complex, it’s hard to be precise. This forces us to stop and think: Do we really understand what’s involved here? If not, it’s probably not a “3”, it’s maybe an “8” or even a “13.”
We’re not estimating time, we’re estimating effort
This is key. A “3” doesn’t mean three hours or three days. It just means this task feels like a medium lift compared to a “1” (super quick) or a “13” (something big, with lots of dependencies). It’s about relative effort. And because it’s based on feeling and experience, not math, it encourages conversation.
How we use it in practice
Every week, when we look at our backlog, we run through the tasks and stories as a squad. Each person gets a chance to weigh in. Sometimes we vote silently, then discuss. Other times we just talk it through.
It’s not about being perfect. It’s about surfacing assumptions, spotting blockers early, and making sure we’re aligned before we commit. And once we’ve got a good rhythm, we can look back and see how accurate we’ve been—which makes future estimates even better.
A tool for alignment, not control
For me, the biggest win has been how this scale creates shared understanding. When a designer estimates something as an “8” and a dev thinks it’s a “2”, that’s a flag for a conversation. Maybe there’s a hidden complexity in the design. Maybe the tech is simpler than we thought. Either way, we’re not guessing in silos anymore—we’re planning as a team.
We’ve also started using a Miro template for this. It’s quick to set up and makes it easier to visualise effort and priorities. If your team is already in Miro for design work, it’s a smooth add-on to your rituals.
Whether you’re running agile sprints or just looking for a more thoughtful way to plan design work, give the Fibonacci scale a try. You don’t need to be a mathematician, just a team willing to have open conversations about effort and complexity.
