Fix your sleep timing and reduce eye strain in 7 days.
Most people’s screens delay sleep without them realizing it.
Automatically adjusts your screen and shows exactly what’s affecting your sleep—and how to fix it.
In 7 days you’ll get:
- Your circadian score
- The main issue affecting your sleep
- A clear next step to improve it
See real changes in your sleep timing within one week.
What you’ll see in 7 days
A clear weekly report that turns screen-light habits into one practical next step.
Blue light at night can affect evening comfort
Your display emits peak blue light around 450 nm, so evening screen sessions can feel harsh without warmer color controls.
Evening Wind-Down
Warmer evening display settings reduce harsh blue-heavy light during late work sessions.
Next-Day Screen Habits
Consistent screen-light routines make it easier to keep late-night work from carrying into tomorrow.
Eye Strain & Headaches
PWM flicker from display dimming and harsh blue wavelengths can contribute to screen discomfort, especially at night.
Three steps to calmer screen light
CircadianShield runs quietly in your menu bar and adapts your display automatically.
Install
Download CircadianShield and drag it to your Applications folder. No account required.
Set Your Location
Choose from 130+ city presets or let CircadianShield auto-detect your coordinates for precise solar tracking.
It Just Works
Your display color temperature adjusts automatically as the sun moves. Warm at night, bright in the morning.
Everything your display routine needs
Built on documented light-exposure standards, not just a color tint slider.
Solar-Based Filtering
Tracks your sun's real elevation through 11 twilight phases with smooth sigmoid transitions between 1800K and 6500K.
Morning Boost
A 6500K morning boost synced to civil dawn gives your display a brighter, daytime feel when your day starts.
20-20-20 Break Timer
Every 20 minutes, look at something 20 feet away for 20 seconds. Smart pause during video calls and full-screen apps.
Light Exposure Score
An A–F grade based on your screen-light patterns and timing. Track evening-light exposure and routine changes over time.
Ambient Soundscapes
Six nature themes: ocean, rain, forest, creek, wind, night crickets, generated mathematically on-device and synced to solar phases.
Evening Light Tracking
Tracks post-sunset melanopic exposure and optional morning sunlight logs so you can review screen-light habits over time.
Light Dashboard
Daily scores, 7/30/90-day trend charts, screen-time history, and light-exposure logs stored locally.
11 Display Modes
Auto, Movie, Reading, Coding, Presentation, Gaming, Biohacker, Sunglasses, Dark, Custom, and Disabled. One click in the menu bar.
Per-App Profiles
Color-accurate mode for Photoshop, cinema mode for Netflix, coding mode for Xcode. Each app gets the right filter.
PWM Flicker Reduction
Software dimming overlay reduces reliance on hardware backlight dimming for a smoother low-brightness experience.
Smart Automation
Auto-disable in fullscreen, flow detection that defers breaks, inactivity pause, video call detection, and DST smoothing.
100% On-Device
No cloud, no accounts, no telemetry. Solar calculations, settings, light logs, and soundscapes all run locally on your Mac.
Built on melanopic EDI & CIE S 026
CircadianShield uses the CIE S 026:2018 standard to estimate melanopic equivalent daylight illuminance for screen-light tracking. Not just "blue light filtering."
Read the ScienceNight Shift vs f.lux vs Circadian Shield
See why a simple color tint is not enough for precise evening screen-light control.
| Feature | Night Shift | f.lux | Circadian Shield |
|---|---|---|---|
| Color temperature shift | Basic slider | Automatic | 11 specialized modes |
| Light-exposure standard (CIE S 026) | No | Partial | Full implementation |
| Light dashboard | No | No | Light score + trends |
| Evening light tracking | No | No | Post-sunset logs |
| Soundscapes | No | No | 6 solar-synced themes |
| Per-app control | No | Limited | Per-app profiles |
| Deep enough warmth | No (common complaint) | Partial | Down to 1800K |
| Active development | Minimal | Stagnant | Active (2026) |
Read more: Why Night Shift Isn't Warm Enough (And What Actually Works)
Available on your devices
Tune your screen light today
Now available on macOS and Windows. 14-day free trial with full Pro features, no credit card required.