Nightpenny vs Sleep++.

David Smith's minimalist Apple Watch sleep tracker. Paid up front, clean, one purpose — record how long you slept.

Comparisons can be lazy — "we're better at everything, switch today" — and that's not useful to anyone trying to pick the right app for their actual problem. This page tries to be specific: where Sleep++ is the right choice, where Nightpenny is, and what data each app reads.

Side by side

What Sleep++ does well

Sleep++ has been one of the cleanest Apple Watch sleep apps since the platform was new. David Smith ships indie iOS work with a particular discipline — do one thing, do it well, don't bolt on. Sleep++ records how long you slept and a basic stage breakdown, and then it gets out of the way. No dashboards, no scores, no streaks, no upgrade nudges every time you open it.

The data lives in HealthKit, where any other app can read it. Sleep++ respects the platform — same posture Nightpenny tries to take. If you want a sleep recorder with zero ambition past "show me what happened," Sleep++ is hard to beat: a single €1.99 purchase, no subscription, no upsell loop.

What Nightpenny adds

Nightpenny and Sleep++ start from the same place — read HealthKit, respect the user, no cloud sync of sleep data — and then go in different directions. Sleep++ stays minimal. Nightpenny adds the math layer that turns the data into something you can act on:

• A 14-night balance instead of a daily number. Sleep++ tells you you slept 6h 30m last night. Nightpenny tells you you're −4h 12m over the past two weeks — and that the trend over the last seven is "accruing." Different question, different answer.
• The Sunday ritual. A weekly three-minute review where the app proposes specific earlier bedtimes for the week ahead, written into your iOS Calendar. Sleep++ doesn't schedule for you; Nightpenny does.
• The Forecast heatmap. A 7-day × 24-hour grid showing when you've historically run low — useful for noticing that your Tuesday afternoons are objectively worse, not just your imagination.
• The methodology page. The exact recovery formula, the citations to Van Dongen 2003 and Borbély 1982, the deliberate simplifications. If you want to know why the math is what it is, the methodology spells it out.

The depth comes with a subscription past the free install. Sleep++ is one €1.99 purchase and you're done forever; Nightpenny Pro is $6.99/mo or $59.99/yr after the free 14-night ledger. If “pay once, never think about it again” is your principle, Sleep++ wins on that axis alone.

Which one to pick

Use Sleep++ if you want the simplest possible sleep recorder, you trust your own judgement about whether the trend is good or bad, and you'd rather have less UI than more. The one-time €1.99 makes it the cheapest serious sleep app on the App Store over any horizon longer than a few months.

Use Nightpenny if the data alone hasn't been enough — you've been looking at sleep duration for months and still aren't sure whether you're in trouble or fine. The balance answers that question, and the Sunday ritual converts the answer into a plan.

Both apps read the same HealthKit data. You can run both without conflict; the only question is which one you'll actually open during your Sunday morning coffee.

Try Nightpenny for free

Install is free and includes the full 14-night ledger, your first Sunday ritual, manual entry, and a weekly advice card from Pennie. No card needed to try the whole thing. Cancel from iOS Settings if it isn't for you.

See the methodology for the recovery-discount formula and citations, or the glossary for the terms used on this page. Other comparisons: Nightpenny vs Apple Sleep Tracking, Nightpenny vs Sleep Cycle.