The original blue-light filter — free software that warms your screen’s color temperature after sunset and shifts back to daylight in the morning, based on your location.
Our take
f.lux predates macOS’s built-in Night Shift by years and is often the app people mean when they say “blue light filter.” It sets your location once, then automatically warms the display after sunset and returns it to normal in the morning, with manual lighting-profile presets available too. No Mac App Store version — Apple’s sandboxing rules have historically blocked this kind of low-level color control from being App Store-distributable, per the developer. Free for macOS, Windows, and Linux.
- Price
- Free
- License
- Proprietary
- Requires
- macOS; specific minimum version not published on the developer’s site.
- Get it via
- Direct
- Developer
- f.lux Software LLC
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What it does
Location-based scheduling
Set your location once and f.lux automatically warms the display at sunset and restores it at sunrise.
Manual lighting profiles
Tell f.lux what kind of indoor lighting you have for a more accurate warm-color match.
Per-app disabling
Temporarily disable the effect for color-sensitive work like photo or video editing.
f.luxometer
A companion tool for measuring the actual spectral output of your display and other light sources.
The deal
- Free for macOS
- Also free for Windows (personal use) and Linux
- Corporate/site licenses available separately for Windows
Worth knowing: Founded by Michael and Lorna Herf, per the company’s own site. No Mac App Store version — distributed only as a direct download. Addresses the same problem as macOS Night Shift using a similar low-level display API; most people use one or the other rather than both together.
f.lux — questions people ask
Is f.lux free?
Yes — free for macOS, and also free for Windows (personal use) and Linux.
How is f.lux different from Night Shift?
They solve the same problem with a similar approach; f.lux predates Night Shift and adds location-based scheduling, lighting profiles, and per-app disabling that Night Shift doesn’t offer.
Is f.lux free?
Yes — f.lux is free.
Does f.lux work alongside a notch app like Alcove?
Yes — f.lux lives in the menu bar, so it runs happily alongside any Dynamic Island hub or notch app.
Where can I download f.lux?
f.lux is available via Direct.
Reviews
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Listing hand-verified September 18, 2026 from the developer's site and public sources.
Also in display & night mode
Iris
$15 one-time (per major version), 7-day free trialA blue-light filter and screen dimmer with PWM-free brightness control and 9 built-in presets — one-time $15 purchase after a free trial.
Shifty
FreeA free, open-source menu bar app that adds power-user controls to macOS Night Shift — per-app and per-website exceptions, custom schedules, and a quick-toggle slider.
NightTone
Free, with a Lifetime Access unlock via in-app purchase ($4.99 or $9.99, Mac App Store)A blue-light filter with adjustable warm color palettes, sunset-to-sunrise auto-scheduling, and multi-monitor support — free, with a one-time unlock for extra options.
Night Shift Keeper
Free to try; $12.99 one-time to unlock Always OnKeeps macOS’s built-in Night Shift running around the clock instead of resetting at midnight or after sleep — free to try, $12.99 one-time to unlock Always On.