Best Free Online Developer Tools to Use in 2026
A practical, opinionated list of the best free online developer tools worth using in 2026, organized by category so you can find what you need fast.
Aug 08, 2026
Sunrise/Sunset Calculator
Calculate sunrise, sunset, dawn, dusk, and civil/nautical/astronomical twilight times for any location and date worldwide.
Sunrise & Sunset
Enter coordinates to calculate sunrise and sunset times
- Enter coordinates — Input latitude and longitude for your location, or click "Use My Location" for automatic detection.
- Select date — Choose the date you want to calculate sunrise and sunset times for.
- Set timezone — Enter your UTC offset (e.g., -5 for Eastern Time, +1 for Central European Time).
- View results — See sunrise, sunset, solar noon, day length, and all three twilight phases.
Twilight Definitions
Civil Twilight
The sun is 0–6° below the horizon. Brightest twilight phase. Most outdoor activities can continue without artificial light. The horizon is clearly visible.
Nautical Twilight
The sun is 6–12° below the horizon. The horizon is still visible but blurred. Sailors can use the horizon for navigation at sea. General outlines of objects are visible.
Astronomical Twilight
The sun is 12–18° below the horizon. The sky is dark enough for astronomical observations. Faint celestial objects become visible. After this, true night begins.
Golden Hour & Blue Hour
The "Golden Hour" is the first hour after sunrise and last hour before sunset, when sunlight appears warm and diffused. The "Blue Hour" occurs during civil twilight when the sky takes on a deep blue hue.
How accurate are these calculations?
The calculator uses the NOAA solar position algorithm, which is accurate to within a few minutes for most locations. Actual times may vary due to local topography (mountains, buildings) and atmospheric conditions.
What is the 0.833° correction?
Sunrise and sunset are defined as the moment when the upper limb of the sun appears or disappears at the horizon. The 0.833° accounts for the sun's apparent radius (0.267°) and average atmospheric refraction (0.566°).
What causes polar night and midnight sun?
At latitudes above 66.5° (Arctic/Antarctic circles), the sun may not rise or set for extended periods. This is due to the Earth's axial tilt of 23.5° relative to its orbital plane.
How do I find my latitude and longitude?
You can use the "Use My Location" button for automatic detection. Alternatively, you can search for your city on Google Maps or similar services to find the coordinates.
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