Layout device for railing rail members

A layout measuring device for railing rail members, comprising:

• a ruler having an upper surface, a lower surface, a first end at a second end, a width and a longitudinal length between the first end and the second end,
• wherein the ruler has a plurality of spacing guides on the upper surface including a first spacing guide and a second spacing guide adjacent to the first spacing guide along the longitudinal length,
• wherein the first and the second spacing guides each include a placement marker and a numerical scale that each extend in a longitudinal direction,
• wherein the placement marker has a first end and a second end with a length therebetween adapted to approximate a lateral length of a rail member,
• wherein the numerical scale has a first end and a second end,
• wherein one of a) the second end of the placement member is in contact with the first end of the numerical scale or b) the first end of the placement marker is in contact with the second end of the numerical scale;
• and
• an arm adapted for equalizing a length between a first one of the rail members and a first post and a last one of the rail members and a second post, the arm being operatively connected to the first end of the ruler, and having an arm ruler extendable and retractable from the first end of the ruler, the arm including a distal end adapted to be placed at an end of the first post, the arm ruler having an arm numerical scale.