Light Travel Time Calculator

Enter Parameters

How to Use Light Travel Time Calculator:

1. Enter the distance value.
2. Select the appropriate unit (ly, pc, AU, km).
3. Click “Calculate” to compute the travel time with steps.
4. Use “Copy Result” to copy results to clipboard (requires HTTPS).

Important Notes:

• Speed of light \( c = 299792458 \) m/s in vacuum.
• Conversions: 1 ly ≈ 9.461 × 10¹⁵ m, 1 pc ≈ 3.086 × 10¹⁶ m, 1 AU ≈ 1.496 × 10¹¹ m.
• Time output in seconds and years for astronomical scales.
• Assumes vacuum; actual light travel in media is slower.
• Clipboard access requires HTTPS. If copying fails, copy manually.

Light Travel Time Examples:

1. 1 Light-Year:
   Distance=1, Unit=ly
   Time ≈ 3.156 × 10⁷ seconds (1 year)
2. Distance to Proxima Centauri (4.24 ly):
   Distance=4.24, Unit=ly
   Time ≈ 1.339 × 10⁸ seconds (≈4.24 years)
3. Earth to Sun (1 AU):
   Distance=1, Unit=AU
   Time ≈ 499 seconds (≈8.32 minutes)