Tohands
Reinventing the calculator for India's small businesses
Product Designer • 3-4 Months • Seed
Designing a connected calculator that turns everyday calculations into digital business records.
Every calculation a shopkeeper makes eventually becomes a transaction they need to record. Why are those still two separate tasks?
That question became the starting point for this project.
At a glance
Role
Product Designer
Industry
FinTech · Hardware
Product
Smart Connected Calculator
Users
Shopkeepers & Small Business Owners
Focus
Product Strategy · UX Research · Industrial Design · Hardware UX
The story
For millions of small businesses, the calculator is still one of the most frequently used tools.
But once the calculation is done, the real work begins.
The number has to be remembered, written down in a register or entered into a bookkeeping app before the next customer arrives.
That extra step has been part of the workflow for decades.
It feels normal simply because everyone has learned to live with it.
Instead of redesigning the calculator, I wanted to redesign what happened immediately after pressing "=".
The problem
After observing how small retailers handled day-to-day transactions, one thing kept coming up.
The calculator was never the problem.
The gap between calculating and recording was.
Every transaction looked something like this.
It was repetitive, easy to forget and interrupted the natural flow of running a business.
The opportunity wasn't to build a smarter calculator.
It was to remove the second step completely.
The idea
Instead of asking
"How can we make calculators smarter?"
we started asking
"What if every calculation could already be a transaction?"
That shifted the project from designing hardware to redesigning a business workflow.
The solution
The entire experience came down to adding just two buttons.
Cash In
Cash Out
Once a calculation is complete, the user simply classifies whether money is coming in or going out.
That's it.
The transaction is automatically recorded and synced with the companion app.
No rewriting.
No switching apps.
No trying to remember numbers a few minutes later.
Sometimes the biggest improvement isn't adding more functionality.
It's removing unnecessary work.
Connected experience
The calculator becomes the place where transactions begin.
The mobile app becomes the place where the business is managed.
Every recorded transaction syncs automatically, allowing business owners to:
View transaction history
Track cash flow
Monitor income and expenses
Maintain digital records without additional effort
Instead of replacing existing behaviour, the product quietly builds on top of it.
Experience evolution
The workflow becomes shorter while still feeling familiar.
Designing the hardware
The interaction changed.
The calculator didn't need to.
The physical design stayed intentionally familiar so existing users wouldn't feel like they were learning a new device.
The focus was on:
Clear keypad hierarchy
Comfortable everyday use
Familiar layout
Space for two new actions without increasing complexity
Innovation came from behaviour, not novelty.
Process
The project evolved through quick cycles of understanding, sketching and testing.
Each iteration moved closer to a solution that felt new without asking people to behave differently.
What I learned
Working on this project changed how I think about innovation.
I realised people rarely need completely new tools.
More often, they need existing workflows to get out of their way.
The best ideas don't always come from adding features.
Sometimes they come from removing a step people stopped questioning years ago.
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