The nap timer built for N2 sleep
Power nap like a sleep researcher.
The timer starts when you fall asleep.
The only nap app optimized for the N2 power nap zone — the sleep stage that restores alertness, sharpens memory, and never leaves you groggy.
Coming soon App Store20 minutes of the right sleep
changes everything.
N2 is the second stage of sleep — the one that makes naps actually work. It's where your brain fires sleep spindles that consolidate memory, restore alertness, and sharpen learning. Stay in it and you wake up sharp. Slip past it into deep sleep and you wake up worse than before.
Nap Smart. Wake Refreshed.
N2nap is designed around one goal: maximize the time you spend in N2 sleep. It detects sleep onset, times your nap from there, and wakes you before you slip into deep sleep — so every session lands in the window where naps actually pay off.
N2nap ensures you get the full restorative sleep you set out for.
The science
The science behind N2nap isn't theoretical — it's built on decades of sleep research. Here's what the data says about naps, timing, and why the N2 window matters.
A meta-analysis of 1,427 effect sizes found sleep spindle activity during N2 is one of the strongest predictors of memory benefit.
Spindle-memory meta-analysis, 2023of ~30-minute naps end in deep sleep — vs. only 6.3% at 10 minutes. The N2-to-N3 boundary is narrow, and timing from onset is how you stay on the right side of it.
Cousins et al. 2023, SLEEPof sleep inertia when waking from N2. Naps that stay in N1 + N2 produce minimal grogginess — the fog comes from N3.
Hilditch et al. 2017In the NASA nap study, pilots who got ~26 minutes of actual sleep — almost entirely N2 — showed a 34% improvement in performance and 54% improvement in alertness. Those 26 minutes were measured from sleep onset, not from when the pilots closed their eyes. N2nap uses the same approach.
Rosekind et al. 1995, NASA Technical Memorandum 108839
No subscription. No account.
No data leaves your device.
N2nap is built on a simple principle: a nap app shouldn't need your email, your credit card every month, or your data on a server.
Full nap timer with all presets, sleep onset detection, haptic wake, history, and Apple Health sync.
$0An adaptive preset that learns your ideal nap length over time. Stay tuned.
coming soonFrequently asked questions
N2nap monitors your heart rate trend and wrist movement using Apple Watch sensors. When it detects the sustained stillness and heart rate drop associated with sleep onset, it starts your nap countdown. The approach is calibrated to be conservative — it's better to start the countdown slightly early than to miss onset entirely.
Apple Watch Series 4 or later, running watchOS 10 or newer.
No — and we won't claim otherwise. Consumer wearables can't reliably distinguish between specific sleep stages in real time. What N2nap does is detect sleep onset accurately, then use research-backed durations to keep your nap in the zone where N2 sleep occurs and deep sleep hasn't started. That's a more honest and more reliable approach.
N2nap has a configurable time-in-bed limit (default 45 minutes). If you don't fall asleep within that window, the session ends and the app provides troubleshooting tips. No nap data is recorded.
A regular timer counts from when you press Start. If you take 12 minutes to fall asleep with a 20-minute timer, you get 8 minutes of actual sleep. N2nap counts from when you fall asleep, so you get the full 20 minutes regardless of how long it takes to drift off.
No. N2nap is completely free. No subscription, no recurring charges, no ads.
On your devices only. N2nap has no server, no cloud sync, and no account system. Nap data syncs between your Apple Watch and iPhone locally. If you enable Apple Health integration, naps are also written to Apple Health on your device.
Deep dives
Sleep science, nap research, and the thinking behind N2nap.
Napping may keep your brain younger — here's the study
A study of nearly 380,000 people found that habitual napping is linked to larger brain volume. Here's what the research actually shows — and what it doesn't.
Read article →Why waking from deep sleep feels terrible
That post-nap grogginess has a name: sleep inertia. Here's what causes it, how long it lasts, and how to avoid it.
Read article →The real reason 20-minute naps don't work
You've heard the advice: take a 20-minute power nap. But most people measure it wrong. Here's the one variable that changes everything.
Read article →NASA nap study: what it actually measured
Everyone cites the NASA nap study. Almost nobody gets it right. Here's what the protocol actually looked like — and why it matters for how you nap.
Coming soonYour body knows how to nap. Now your watch does too.
Free download. No account required.
Coming soon App Store