A +1.5 spread is commonly seen in baseball betting, the standard runline  for MLB. This spread means the underdog must win outright or lose by exactly one run to cover the spread. Alternatively, a -1.5 spread means that the favorite must win by at least two runs. Many baseball games are decided by fewer than two runs.

This Share. When betting on an MLB run line, +1.5 means that the underdog team must either win the game outright or lose the game by one run or less in order for the bet to be successful. With a run line, also called against the spread,  the spread is almost always 1.5 runs.