What is ROI in betting?
ROI, or return on investment, is a bettor's net profit divided by the total amount staked, shown as a percentage, and it measures how efficiently bets have turned stakes into profit.
Profit alone tells you little. Somebody who made $500 from $2,000 in bets did far better than somebody who made $500 from $50,000. ROI puts both on the same scale.
ROI = net profit ÷ total staked × 100
US bettors and apps mostly say ROI. European tipsters tend to say yield for the same calculation.
Example
Over a season you place 200 bets at $10 each.
- Total staked: $2,000
- Total returned: $2,120
- Net profit: $120
- ROI: 120 ÷ 2,000 = +6%
For every $100 you put through the bookie, you made $6. That may sound small. Over a large number of bets it’s a very good result, because the bookie’s margin means the average bettor sits somewhere below zero.
Watch out
Two meanings. Some people divide profit by their starting bankroll instead of by total stakes. With a $500 bankroll, the same $120 becomes “24% ROI”. It’s a legitimate number, and it measures something different: growth of the pot. When a tipster quotes ROI, ask which one it is.
Sample size. A +20% ROI over 30 bets is noise. Over 1,000 bets it would be extraordinary. I ignore anything under 300 bets at odds around evens, and I want 1,000 or more at long odds.
Odds that nobody could get. ROI worked out from prices that vanished seconds after the tip went out is fiction. Records should use odds that were widely available.
Cherry-picked windows. “+35% ROI this month” says nothing about the other eleven.
A high win rate doesn’t mean a good ROI either. You can win 70% of your bets at short odds and lose money, which I explain in why hit rate is misleading.