Is 400 nits bright enough for a laptop screen?

400 nits is fine indoors and in open shade, but not enough for direct sun. For that you want 1,000-plus nits to stay readable. Most laptops sit around 300-400 nits, which handles a bright room or a shaded balcony. A cloudy day wants 400-600; full sun starts near 1,000. A MacBook Air tops out around 500 nits and physically can't go higher. A MacBook Pro 14" or 16" reaches about 1,600 nits. But macOS caps your everyday brightness near half that and holds the brighter range in reserve. MacBrightness opens that cap on the keys you already press, $5 one-time, and the free Splitscreen Mode lets you see it first.