How much am I losing?

Hi,

New to sportsbetting and this forum.
Can someone please explain/outline to me roughly what percentage of my investment I would lose in the long run putting random bets on the moneyline on favourites?
Would this differ between sports?
Would the result be different if I were to bet underdogs?
Would the result be different if I bet the point spread?

Any answers really appreciated as I asked this question on the sbr forum and got no reply... Maybe it's really obvious but I cant figure it out.. I know bookmakers charge about 4.5% vig but Im not sure how that applies to the moneyline.. I Also read that bookmakers often take more bets on one side to increase there profit margin.. Though Im not entirely sure that the bookmakers profit is tied to my loss rate..

Impossible to answer since different books will be offering different lines. -330 / +260 one place is obviously a different commission than a sports book that has -320 / +270 on the same game. A google search for 'no-vig calculator' will tell you how to calculate it yourself for whatever the line is.

I have posted 2 links here for you. The first link is the Wizard's money line house edge calculator. The 2nd link gives you the formula to figure it out for yourself. Books often do accept more money on the favorite and adjust the line to make the favorite a worse bet than it should be. In the long run you would gain by betting just underdogs but you wouldn't come close to overcoming the vig; you would just reduce your loss by a little bit. To the books that little bit they gain adds up to a lot over time. Against a traditional spread you would have to win 52.4% of your bets to break even. You would lose slightly more than the vig if you randomly bet the favorite. Most of the time the books use a formula for the money line which is based on the spread. Some Vegas books have cried that they've taken a very bad beating when the favorite wins the Superbowl and they have accepted a lot more money on the favorite. But I don't feel too sorry for them.

https://wizardofodds.com/games/sports-betting/straight-bet-calculator/

http://derekbets.com/2010/09/21/how-do-money-line-odds-work-part-ii/