TargetSplits is a pace planner for Concept2 erg tests and races. You set a target time or distance, break it into segments, and adjust the effort for each one by swiping or typing. It shows the time, distance, average split and watts for every segment, and draws the pace profile so you can see the shape of the plan before you sit down to row it. It’s free, it needs no account, and it loads instantly on a phone next to the erg — which is where it gets used.

Why it exists

Rowers work out the split they need to hold for a 2k, a 5k or a 30-minute piece more often than almost any other calculation in the sport, and the existing calculators were dated, fiddly on a phone and stopped at the average. The average isn’t the plan: nobody rows a 2k flat. I wanted one tool that did the single job well and then helped with the part the others ignored, which is how to distribute the effort.

How it works

Enter what you’re rowing: a distance with a target time, or a time with a target distance.
Choose how many segments to split it into — quarters for a 2k, five-hundreds for a 5k, whatever you think in.
Adjust each segment. Swipe or type a split or a wattage and the others rebalance so the overall target still holds. The table and the pace profile update as you go.
Row it. The plan is on your phone; the numbers are what you need to see on the monitor.

There’s a separate split calculator for the plain conversion — split to watts, watts to split, time to distance — when that’s all you need.

Results

3,700 users in under three months from launch in 2024, with no marketing beyond the rowing community passing it around.
Still no marketing budget. Growth is word of mouth from coaches and squads sharing a plan.

Design

One calculation, front and centre, with results updating as you type or swipe.
Mobile first, because it gets used next to an erg.
No accounts, no dependencies, loads instantly.

How it was built

TargetSplits started as a personal challenge to improve on the traditional tools and, at the same time, to see how far AI-assisted code generation could take a small, well-defined product. The answer was: most of the way to launch, with the remaining effort going into the interaction design — making swipe-to-adjust feel right on a phone took far longer than the arithmetic.

Elsewhere

TargetSplits pace planner and the split calculator
Related: Fantasy Rowing and WinterRowingLeague, for when the erg season turns into the racing season.

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