The Problem
Before a run, I wanted to quickly work out my target pace – if I’m running 5km, what pace do I need to hit a certain time? Back in 2016, there weren’t as many quick tools for this sort of calculation, especially not on your wrist.
I needed something I could check before heading out, without pulling out my phone.
What It Did
Pace Calculator was a simple utility for runners on the Pebble watch:
- Calculate target pace based on distance and time
- Calculate distance based on pace and time
- Calculate running time based on distance and pace
- Work out expected start or end times for your run
- Support for both kilometres and miles
It was a planning tool rather than a tracker – useful for working out your numbers before a run, not during it.
Technical Details
Built in C for Pebble OS. The calculations themselves were straightforward, but the interface needed to be simple enough to use quickly while you’re getting ready for a run.
The app achieved 657 installs on the Pebble platform.
The Android Wear Version
Unlike Health Sync where I got caught in feature creep, Pace Calculator was simple enough that I successfully ported it to Android Wear 2.0 and published it on the Google Play Store.
The core functionality remained identical to the Pebble version:
- Calculate target pace before a run or jog in kilometres or miles
- Calculate distance based on running time and pace
- Calculate running time based on distance and pace
- Work out expected start or end time for your run
The Android version added interface improvements suited to the platform:
- Navigation drawer optimised for circular watches
- Ambient mode support for always-on display
- Time split calculations
- Better settings management and onboarding
I eventually delisted it as more comprehensive running apps with built-in pace calculators became standard, making a standalone calculator redundant.
The lesson from Health Sync stuck: keep the scope focused, ship the core functionality, then add features incrementally rather than all at once.
Why I Built It
I was running regularly and wanted a quick way to plan my paces without pulling out my phone. The watch was already on my wrist, so it made sense to have the calculator there too.
The Pebble version is preserved in the Rebble app store.
