Betting analytics glossary
What is ROI in Sports Betting?
ROI is the finance-world return metric everyone borrows into betting, then everyone uses to mean something slightly different. The clean definition, and the two other numbers it’s constantly confused with, in one page.
The short definition
Return on Investment (ROI) is total net profit divided by the capital you invested, expressed as a percentage. In plain finance terms: how much did the money you put to work actually earn you.
Where this gets muddy in betting is the word “invested”. Two schools of thought coexist: some sites use ROI to mean profit divided by total stake (which is really yield), others reserve ROI for profit divided by bankroll deployed (which is closer to ROC). Neither usage is objectively wrong. Both are common. The important habit is to check what a source means before comparing two ROI figures.
The formula
ROI % = (Profit ÷ Capital Invested) × 100Profit is net (returns minus stakes). Capital invested is whichever denominator the source uses:
- Stake-based ROI: denominator = sum of every stake ever placed. Numerically identical to yield.
- Bankroll-based ROI: denominator = the amount of money you actually deployed as a bankroll (the pot you were staking from). Numerically identical to ROC.
Worked example
You start with a 100u bankroll. Over a season you place 300 bets at an average stake of 1.5u each, so total stake = 450u. Net profit = 27u.
- Stake-based ROI (a.k.a. yield): 27 ÷ 450 = 6.0%
- Bankroll-based ROI (a.k.a. ROC): 27 ÷ 100 = 27%
Same 27u profit. Same season. Two headline numbers that differ by 4.5x depending on which denominator the writer picked. Both are “correct” ROIs. Neither is lying. This is why the distinction matters when comparing tipsters.
Which denominator should you use?
Depends on the question you’re trying to answer.
- “How good is my staking system per bet?” Stake-based. Removes bankroll size from the picture and lets you compare bettors with wildly different bankroll scales.
- “How productively is my money working?” Bankroll-based. Answers the actual finance question about return on capital deployed, which is what a professional would care about if they were choosing between putting money into betting versus somewhere else.
- “How confident should I be in my edge?” Neither of these on its own. Look at Closing Line Value (CLV). Yield-flavoured ROI takes thousands of bets to become statistically meaningful; CLV gives signal in dozens.
Where ROI gets dishonest
Two common patterns to be sceptical of:
- Silent switching of the denominator. A tipster reports 27% “ROI” on a landing page and it turns out they meant bankroll-based, but you assumed stake-based when you compared them against someone quoting 6% yield. The two are the same bettor. Always verify.
- Variable stake sizes with a bankroll-based ROI headline.A tipster who stakes bigger on the confident picks can push their bankroll-based ROI up sharply while their per-bet edge (yield) is mediocre. Sometimes this is legitimate Kelly staking; sometimes it’s cherry-picking loud winners with big stakes and quiet losers with small ones.
The three numbers, side by side
- Yield: profit ÷ total stake. Per-bet-normalised. The tipster industry’s default.
- ROI (stake-based): mathematically identical to yield. Common on European sites.
- ROI (bankroll-based): mathematically identical to ROC. Common on US sites and in finance-flavoured writeups.
- ROC: profit ÷ bankroll deployed. The true money-on-money return.