How the light speed distance formula works
Light moves at a constant speed in a vacuum, so the distance it covers is simply its speed multiplied by the travel time. This is the same idea as distance = speed × time you learned in school, just with a very big speed.
distance = speed of light × time
c = 299,792.458 km/s = 186,282 miles/s
Worked example
How far does light travel in one hour? Multiply 299,792 km/s by 3,600 seconds: 299,792 × 3,600 = 1.079 billion km (about 671 million miles), also known as one light-hour.
Frequently asked questions
How far does light travel in one second?
About 299,792 kilometers (186,282 miles) in a vacuum, fast enough to circle Earth about 7.5 times in a single second.
How far does light travel in one year?
About 9.46 trillion kilometers (5.88 trillion miles). This distance is called one light-year.
What is the speed of light?
Exactly 299,792,458 meters per second, or about 186,282 miles per second (roughly 671 million miles per hour).
How far does light travel in one minute?
About 17.99 million kilometers (11.18 million miles), known as one light-minute.
How is light-travel distance calculated?
Multiply the speed of light by the time: distance = c × time. One hour equals 299,792 × 3,600 ≈ 1.079 billion km.
How far is a light-year in miles?
About 5.88 trillion miles, the distance light covers in a year at 186,282 miles per second.