Units to risk or units to win: how -150 and +150 differ in a record

A unit can mean the amount you risk or the amount you want to win. At -150, one unit risked wins 0.667 units, and one unit to win risks 1.5 units. On the same results the two conventions give different totals, and sometimes opposite signs, so a record in units is only readable once you know which one it uses.

The unit size calculator converts between a risked unit and a unit to win at any price.

The two conventions

Risk one unit. Every bet costs 1 unit if it loses. A win pays the price: 0.667 at -150, 1.5 at +150, 0.909 at -110. This is the convention behind most flat-staking records.

Win one unit. Every bet pays 1 unit if it wins. A loss costs the amount needed to win that unit: 1.5 at -150, 0.667 at +150, 1.1 at -110. Some people use it because it makes favourites and underdogs pay equally.

Converting a stake

From risk R to win W at decimal price d: W = R × (d − 1). From win W to risk: R = W ÷ (d − 1). At -150, d = 1.667 and d − 1 = 0.667. A bet to win 1 unit therefore risks 1 ÷ 0.667 = 1.5. At +150, d − 1 = 1.5, so to win 1 unit you risk 0.667.

Ten bets at -150, seven winners

Risk-one convention: 7 × 0.667 − 3 × 1 = +1.67 units on 10 units staked. Win-one convention: 7 × 1 − 3 × 1.5 = +2.5 units on 15 units staked. The totals differ, but 1.67 ÷ 10 and 2.5 ÷ 15 are both 16.7%. When every bet is at one price, the return on the amount staked is the same either way, and only the unit changes. It is when prices are mixed that the conventions part ways.

Which does a published record use

Without a stated convention, you cannot tell. A line such as "+12 units" from a pick service could be a sum of risked units, a sum of to-win units, or neither, if stakes were varied by confidence. A readable record states its convention, lists the price on each bet and does not move the definition of a unit partway through. The article on what a unit is gives the basic definition, and units and comparable records covers why the denominator has to stay fixed.

What to use for your own log

• Pick one convention and write it at the start of the log.
• Record the actual stake in money as well as in units, so the record can be rebuilt under the other convention if needed.
• If you follow someone else's picks, check what their unit means before you set your own. Their unit is a fraction of their money, not yours, and your unit is chosen from your bankroll as in the unit-from-bankroll article.

Why to-win staking can push stakes up

Staking to win a unit raises the amount at risk on heavy favourites. At -400 you risk 4 units to win 1, and one loss wipes out four wins. The convention hides that the bankroll exposure of each bet is not equal. A log that tracks risk per bet shows it, and a log that tracks only the to-win unit does not.

Convert it. Enter a price and a stake in the unit size calculator to see the amount risked and the amount won under each convention.