Tau Ceti is about 12 light‑years away from Earth.

In kilometers, that’s roughly 12×9.46×1012≈1.1×101412\times 9.46\times 10^{12}\approx 1.1\times 10^{14}12×9.46×1012≈1.1×1014 km (about a hundred trillion kilometers), so even traveling at the speed of light it would take around 12 years to get there.