# How big is the universe in km?

The diameter of the observable universe is about

The observable universe has a diameter of approximately 46.5 billion light years, or 4.40 x 10^23 km.

Observable Universe as a source

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It's quite big

The universe has a mass of approximately 46 billion light years, or billions of light years. One light year is equivalent to 9.461e+12, so that number is even uncountable. Similarly, 46 billion light years is equivalent to 4.35193601739e+23, so that number is sort of countable. I hope you got the idea.

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The observable universe is approximately 93 billion light-years in diameter, which is roughly 8.8×10^26 kilometers.

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