Convert from button measure to gigameter

Unit Definition (button measure)
The button measure is a unit of distance equal to 1/40 inch (0.635 millimeter), used to measure the thickness of buttons.

Unit Definition (gigameter)
The Gigameter (or Gigametre) a metric unit of distance equal to one million kilometers or about 621,371.2 miles. It is seldom used, but this unit would be a good yardstick for the inner Solar System: the distance from the earth to the sun is about 149.60 gigameters.