LapPacer for iPhone

Opening LapPacer on your iPhone runs its own independent pacing session — separate from, and not connected to, whatever the Apple Watch app is doing (see the Watch Instructions for that), with no Health dependency of its own. It's a simpler display than the watch app's: a continuously climbing pace-projection number, rather than the watch's ahead/behind-target distance gap.

Getting Started

The first time you open the app, a splash screen explains how it works and links to this site. Tap Continue to reach Setup. A Back button on Setup returns you to the splash screen if you want to re-read it.

Setup

• Lengths — the total number of pool lengths for the whole set.
• Segments — splits the lengths into that many equal repeats, each with its own target pace. The counter resets to 0 at the start of each segment. Lengths must always be evenly divisible by the segment count, so the app automatically snaps both values to valid combinations as you adjust them.
• Minutes / Seconds — the desired/target total time for the entire set.
• Secs / Length — your target pace, in seconds per length. This is simply Minutes/Seconds divided by Lengths, so it updates on its own whenever you change either of those. You can also adjust it directly, and Minutes/Seconds will be recalculated to match — handy when you know the pace you want to hold but not the total time it works out to. Adjusting it steps to whole seconds (a set working out to 9.6 goes to 10, not 10.6), and the length count is never changed.
• Want a pace between whole seconds? Adjust Seconds instead and watch Secs / Length follow. Adding or removing one second of total time spreads across every length, so how finely it moves depends on your set: over 10 lengths each second shifts the pace by a tenth (9.6 → 9.7), while over 72 lengths it takes about seven seconds to move the pace by a tenth. Use Secs / Length to get close, then Seconds to fine-tune.
• Countdown (sec) — how long the "Get Ready" countdown runs before the length counter starts. Set it to 0 to skip the countdown entirely.

Tap any +/− button to adjust a value, and hold to change it continuously.

Starting a Set

Tap Start. Your settings are saved on your phone and loaded automatically next time. The "Get Ready" countdown appears in yellow, giving you time to get in position. Once it reaches zero, the pace number begins climbing.

Reading the Display

While you swim, the number on screen climbs steadily in real time, following your target pace exactly — regardless of which length you're actually on. It's a live projection of the length you should be finishing if you're swimming exactly on pace, not a count of the lengths you've actually completed. It's always shown in the same bright green, to one decimal place (e.g. 5.8) — every time you touch the wall, glance at it and compare both parts to the length you just finished:

• Whole number lower than the length you just finished — you're ahead of pace. The target hasn't caught up to how far you've actually swum.
• Whole number higher than the length you just finished — you're behind pace. The target has already moved past where you are.
• The decimal — exactly how close the target is to ticking over to the next whole number. A low decimal (close to .0) means there's still room before it does; a high one (close to .9) means it's about to, which shifts the gap between you and it — closing it if you're ahead, widening it if you're behind.

No math required mid-swim — just glance at the number and compare it to the length you touched.

The iPhone app rotates automatically — turn your phone sideways and the display rotates with it, no manual tapping required. The watch app's display doesn't rotate at all, since it's meant to be read on your wrist rather than propped up at an angle. Landscape also gives the number more room to stay full-size with the extra decimal digit.

Stopping a Set

Press and hold the display for about a second to stop the current set and return to Setup. There's no on-screen reset button while a set is running — this keeps the whole screen dedicated to the pace number. A reset button does appear on the finished screen after a set completes normally.

Finishing

When the final segment completes, the display shows the total lengths completed and the total time for the set, both in green.