Comparison
Sundown vs f.lux: Which Mac Blue Light Filter Is Better?
One blocks 40%. The other blocks 97%. Here’s the full comparison.
Feature
Sundown
f.lux
Filtering depth
500K (97% blocked)500K (97% blocked)
~1900K (40% blocked)
Last updated
June 2026June 2026
June 2023
Flicker protection
Flicker-free gammaFlicker-free gamma
App size
398KB398KB
~20MB
Brightness control
F1/F2 keysF1/F2 keys
Scheduling
Auto-sunset + customAuto-sunset + custom
Basic
Anti-dithering
Apple SiliconApple Silicon
Price
$4.99/mo (7-day free trial)$4.99/mo (7-day free trial)
Free
f.lux blocks 40%. Sundown blocks 97%.
f.lux was groundbreaking in 2009. But it hasn’t been meaningfully updated since 2023. Sundown is native macOS, built for Apple Silicon, with flicker-free dimming and 97% blue light blocking at 500K.
97%
Blue light blocked at 500K
58%
More melatonin produced
7 min
Faster to fall asleep
Sources: Burkhart & Phelps 2009, Heo et al 2017, Esaki et al 2016
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