The graphics on these pages note New Horizons' distance from Earth, the Sun and Pluto in AU, or Astronomical Units. One AU is the average distance between the Sun and Earth, about 93 million miles or 149.6 million kilometers.
Heliocentric Velocity
The current position graphic also notes the spacecraft's heliocentric velocity - its speed with respect to the Sun - in kilometers per second. One kilometer per second is equivalent to 0.62 miles per second, or 2,237 miles per hour.