When it comes to rockets, size matters, and Elon Musk and Jeff Bezos know it. The two billionaire entrepreneurs both own their own spaceflight companies.

Musk's SpaceX is currently using its large Falcon 9 rocket to fly large payloads to orbit for NASA and companies around the world, while Bezos's Blue Origin is testing out its New Shepard rocket designed to fly humans on suborbital flights to the edge of space.

Bezos and Musk have a friendly rivalry when it comes to spaceflight, having sniped at one another on Twitter about their wide and varied space accomplishments. So, at the end of the day, whose rocket is really the biggest?

When it comes to size, there's really no contest. SpaceX's Falcon 9 is a full 170 feet taller than Blue Origin's New Shepard. The Falcon 9 stands at 230 feet tall, and New Shepard comes in at a mere 60 feet.

That said, NASA dwarfs them both.

The Saturn V rocket that brought people to the moon for the first time stands at 363 feet tall, more than 100 feet taller than the Falcon 9 or SpaceX's next large rocket, the Falcon Heavy, set to fly its first test in January 2018.

Blue Origin's three-stage New Glenn rocket, when it's built, should rival the Saturn V. That rocket is expected to stretch to about 313 feet high.

But look, we don't want to get into some petty rocket-measuring contest.

Both Bezos and Musk's rockets have their places in the industry.

The truth is, the Falcon 9 and the New Shepard do two very different things. The New Shepard is designed to ferry paying customers to about 100 kilometers above the Earth before they come back down under parachutes safely within a capsule.

The Falcon 9, on the other hand brings large payloads to orbit and could one day fly humans up to the International Space Station, if all goes as planned.

That said, both the Falcon 9 and the New Shepard are designed for reusability, coming back down to Earth after flying payloads to orbit or on a suborbital journey.

As a general rule, a larger rocket like the Falcon 9 will take you farther into space, insert you into orbit, and get whatever you're trying to send into the vast unknown there with more aplomb.

That's not to say small rockets don't have their place in the industry (and in our hearts) however.

Smaller launchers, like Blue Origin's New Shepard, can be a better fit for people trying to send little payloads to orbit or the edge of space.

You don't want to waste all that fuel you'd need to launch a large rocket on something that can be launched with something smaller, right?

Really, at the end of the day, the size of a rocket is always less important than how you use it.