How a Cup of Coffee Led to the Pursuit of the Best Travel Currency Converter

Clean Shaven Apps
Published in
3 min readApr 13, 2017


The coffee scale that I bought at a steal while I was in Hong Kong.

When I was in Hong Kong last October, I bought a coffee weighing scale for HK$98 from a cafe. While I was at it, I bought a cup of filter coffee for HK$78.

I remember weighing scales that can weigh to a precision of 0.1g don’t come cheap, and it was bargain that I was able to get one at HK$98 (US$12.60).

After making payment, I started thinking about my cup of coffee. More specifically, how much that cup of coffee had cost me.

HK$98 was a steal for the scale, but HK$78 for a cup of coffee?

After performing some arithmetic in my head, I was shocked.

I knew buying fancy coffee outside is expensive, but I had never paid anything near US$10 for a cup of black coffee anywhere in my life.¹

I’m terrible at mental arithmetic, and I find it such a hassle to take my iPhone out to perform a currency conversion. Moreover, I always find it embarrassing to hold up the cashier while I mess around with my phone.

The first mockup of Elk on Apple Watch that I came up with, one day after I came back from my trip to Hong Kong.

I just assumed that a cup of black coffee couldn’t have cost more than US$5–6 anywhere in the world.

That US$10 coffee had such a profound impact on me.

I was determined to find a way to quickly figure out how much something cost in my own currency when I’m travelling — without digging into my pocket, unlocking my phone, launching an app, or punching in numbers.

Sure there are plenty of currency converters out there, but they were either showing too much information, too cumbersome to input quickly (imagine dictating the value to your Apple Watch while the cashier and the rest of the queue stares at you). None of them appealed to me visually.

The instant launch apps and the Digital Crown access introduced in watchOS 3 seemed like perfect fit for the problem I was trying to solve.

A second iteration of the initial design of the Apple Watch app.

Five months, three trips, 3,777 Slack messages and many iterations later, we think we got it.

Today, we’re launching Elk. We think it’s the best way to figure out how much things cost while you’re travelling, really quickly.

It’s free to download. An in-app purchase is required to unlock all currencies. A 14-day free trial is available so you can test it on your own trips.

While we think our Apple Watch app is the fastest way to figure out how much things cost on your trips, we know not everyone has an Apple Watch.

If you only have an iPhone, you’ll find Elk to work admirably as well on it. The iPhone app is an entirely different beast, and deserves a separate story on its own.

In the meantime, we hope you’ll never get a shock at how much you’re paying for your coffee, ever again.

  1. After that experience, I learnt that filter coffee almost always cost about US$10 in Hong Kong. Perhaps manpower is really expensive in Hong Kong, and filter coffee is after all a time-consuming coffee to make. An Americano or Long Black, on the other hand, cost about half the price of filter coffee. ↩︎



Clean Shaven Apps

I make apps. I started with Due. Then Dispatch, Clips, Timers, Alive, pico and most recently, Elk.