Lightning Distance Calculator
Calculate how far away lightning struck using the flash-to-thunder delay
See the flash → Start timer → Hear thunder → Stop timer
// How It Works
Light travels at ~300,000 km/s (essentially instant). Sound travels at ~343 m/s at 20°C. The delay between flash and thunder tells you the distance.
// Temperature Effect
Sound speed = 331.3 + 0.606 × T(°C) m/s. At 0°C: ~331 m/s. At 30°C: ~349 m/s. Warmer air = faster sound = slightly shorter calculated distance.
// 30/30 Rule
If the flash-to-bang time is 30 seconds or less (~10 km), seek shelter immediately. Stay sheltered for 30 minutes after the last thunder.
// Safety Tips
Avoid open fields, tall trees, and water during storms. Get inside a building or hard-topped vehicle. Crouch low if caught outside — don't lie flat.
// How to Use Online Lightning Distance Calculator
- Enter or paste your source data into the tool input.
- Click the primary action button to run Online Lightning Distance Calculator.
- Review the output, then copy or export your result.
// FAQ: What does Online Lightning Distance Calculator do?
Online Lightning Distance Calculator helps you calculate how far away lightning struck using the flash-to-thunder delay in your browser with instant results.
// FAQ: How do I use Online Lightning Distance Calculator?
Paste or type your input, choose the needed action, and copy the generated output when the result is ready.
// FAQ: Is my data safe when using Online Lightning Distance Calculator?
Yes. Processing runs in your browser session for this page, so your content is not uploaded by this tool workflow.
// FAQ: Can I use Online Lightning Distance Calculator on mobile devices?
Yes. Online Lightning Distance Calculator works on modern mobile browsers, so you can run it from phones and tablets.