Speed of Sound & Distance Calculator

Calculate temperature-adjusted speed of sound in air or other media, and determine distance from lightning-to-thunder delays or sonar echo reflections.

Acoustic Parameters

Count seconds between seeing lightning flash and hearing thunder.
Calculated Distance 1.07 miles
1,717 m
1.72 km (5,633 ft) from sound origin
Speed of Sound (c) Mach 1.00
343.4 m/s
1,236 km/h · 768.2 mph · 1,127 ft/s

Distance & Velocity Reference

Metric Distance: 1,717.1 m (1.72 km)
Imperial Distance: 5,633.4 ft (1.07 miles)
Rule of Thumb (Air 20°C): ~3 seconds per km (~5 sec per mile)
Acoustic Velocity in Knots: 667.6 knots
Wavelength at 1 kHz (λ = c/f): 34.34 cm (13.52 in)

Comparative Speed in Other Media

Air (20°C / 68°F): 343.4 m/s (768 mph)
Fresh Water (20°C): 1,482 m/s (3,315 mph)
Sea Water (20°C, 3.5%): 1,522 m/s (3,405 mph)
Pyrex Glass: 5,640 m/s (12,616 mph)
Structural Steel: 5,960 m/s (13,332 mph)

About this tool

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