A sports betting strategy that can win over time rests on two things you control: betting only when your estimate of a result beats the price, and staking a fixed, small share of your bankroll so a losing run does not end you. Everything else on this page, from line shopping to the Kelly criterion, is a way of doing one of those two things, and the staking systems that promise more (Martingale, Fibonacci, Labouchere) change when you win and lose, never the expected value of a bet.<\/p>\n\n\n\n
A price is a probability. At -110 the book is asking you to risk $110 to win $100, which implies a 52.38% chance (110 divided by 210). Post -110 on both sides of a game and the two add up to 104.76%. That extra 4.76% is the margin the book keeps, and it is why a bettor who picks winners exactly half the time at -110 loses about $4.55 for every $100 risked.<\/p>\n\n\n\n
So the break-even line at -110 is 52.38%, not 50%. Our guide to how betting odds work<\/a> has the conversion for every format.<\/p>\n\n\n\n Two books can price the same side differently. Take a -105 instead of a -110 and your break-even drops from 52.38% to 51.22%. Over 500 bets that is the difference between needing 262 winners and needing 257.<\/p>\n\n\n\n Half a point on a spread works the same way. A -3 that becomes -2.5 turns a three-point win from a push into a winner. You can follow current NFL lines on our NFL predictions<\/a> hub, and the point spread guide<\/a> explains how spreads grade.<\/p>\n\n\n\n Value betting means one thing: your estimate of a result is higher than the probability the price implies. The expected value of a $100 bet is your chance of winning times the profit, minus your chance of losing times the stake.<\/p>\n\n\n\n A worked example. A team is +150, which implies 40.0%. If your own estimate is 45%, the bet is worth 0.45 x $150 minus 0.55 x $100, or +$12.50 per $100. If your estimate is 40%, it is worth nothing, and below that it loses. The hard part is the estimate, and a strategy that cannot say where its 45% came from is guessing.<\/p>\n\n\n\n A unit is a fixed share of your bankroll, set once. At 1%, a $1,000 bankroll bets $10 a unit, and a run of 10 straight losses costs $100, a tenth of the roll. At 10% a unit, the same run takes the whole thing. Our guide to betting units<\/a> shows how to record results in units, so a $50 bettor and a $500 bettor can compare records.<\/p>\n\n\n\n Flat staking, the same unit on every bet, is the plain version. At $10 a unit and -110, no single loss costs more than $10 and every win pays $9.09, so one loss undoes one win and 91 cents more.<\/p>\n\n\n\n Kelly sizes each bet by your edge. The share of bankroll to bet is (b x p – q) \/ b, where b is the profit per $1 staked, p is your chance of winning and q is your chance of losing.<\/p>\n\n\n\n At +150 with a 45% estimate, b is 1.5, and Kelly says (1.5 x 0.45 – 0.55) \/ 1.5 = 8.3% of the bankroll. At -110 with a 55% estimate, it says 5.5%. Those are large bets for a number you estimated yourself, and half Kelly (4.2% and 2.75% here) halves each of them. If p is too high, full Kelly overbets, and an estimate at or below the break-even gives zero or a negative number: no bet.<\/p>\n\n\n\n A two-leg parlay of -110 bets pays about +264. Two fair coin flips would pay +300, so the book’s margin compounds with every leg. The two-leg ticket implies 27.4% against a true 25% for two 50% legs. At three legs the parlay pays about +596 against a fair +700.<\/p>\n\n\n\n A parlay is not a bad bet when every leg carries an edge, since the edges compound too. Without an edge on each leg, it multiplies the margin. The teaser bet guide<\/a> covers the related bet that moves the spread in exchange for a lower payout.<\/p>\n\n\n\n Arbitrage means backing both sides at different books when the two prices add up to less than 100%. Take +110 on one side (47.62%) and +105 on the other (48.78%): together 96.4%. Stake $100 on the +110 side, which returns $210, and $102.44 on the +105 side, which also returns $210. You have staked $202.44 and collect $210 either way, a profit of $7.56, or 3.7%. A price that moves before the second bet is placed turns the arb into an ordinary bet.<\/p>\n\n\n\n A hedge bets the other side of a position you already hold. Say you hold $100 on a team at +1000 to win a title, and it reaches the final with the opponent priced at -130. A bet of $621.74 on the opponent returns $1,100, so whoever wins, you finish $378.26 ahead. You give up the chance at $1,000 profit for a certain $378.26. Our hedge bet guide<\/a> works through more cases, and matched betting<\/a> applies the same arithmetic to sportsbook promotions.<\/p>\n\n\n\n Martingale doubles the stake after every loss. From $10, six straight losses cost $630 ($10, $20, $40, $80, $160 and $320), and the seventh bet must be $640 to win back $10. At 50% per bet, the chance of six straight losses is 1 in 64, or 1.6%. At -110 it is worse: a win after one loss nets $8.18, not the $10 the system promises, because the winning bet pays less than it risks.<\/p>\n\n\n\n The reverse systems press winners instead. The 1-3-2-6 system bets 1, 3, 2 and then 6 units after each win and resets after a loss. At even money, four straight wins make 12 units; a loss on the fourth bet leaves you at zero, and a loss on the first costs one unit.<\/p>\n\n\n\n Fibonacci and Labouchere are slower versions of Martingale. Fibonacci moves one step up the sequence 1, 1, 2, 3, 5, 8, 13 after a loss and two steps back after a win. Labouchere writes a line such as 1-2-3, bets the sum of the two ends (4 units), crosses both off after a win and adds the lost amount to the end after a loss; finishing the line wins its total, 6 units. None of the three changes the chance of any single bet. Each only rearranges when the losses arrive, and a long enough losing run beats all of them.<\/p>\n\n\n\n A handicap gives one side a head start in points or goals so the market is closer to even. A favorite at -3.5 must win by four or more; the underdog at +3.5 covers with any loss by three or fewer, or a win. In soccer a quarter-ball line such as -0.25 splits the stake: half on -0.5 and half on 0, so a draw loses half and returns half.<\/p>\n\n\n\n The strategy question is the same as with any price: is your chance of covering higher than the price implies? Our guide to handicapping in betting<\/a> covers the formats, and the beginners’ guide<\/a> starts from the first bet. If you pay for picks, check the record first in our handicapper site reviews<\/a>: a pick service at -110 has to hit 52.38% just to break even, before its fee.<\/p>\n\n","protected":false},"excerpt":{"rendered":" A sports betting strategy that can win over time rests on two things you control: betting only when your estimate of a<\/p>\n","protected":false},"author":34,"featured_media":210418,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false},"expert-betting-guide-category":[1226],"expert-betting-guide-tag":[],"class_list":["post-96803","expert-betting-guide","type-expert-betting-guide","status-publish","has-post-thumbnail","hentry","expert-betting-guide-category-uncategorized","resize-featured-image"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.scoresandstats.com\/es\/wp-json\/wp\/v2\/expert-betting-guide\/96803","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.scoresandstats.com\/es\/wp-json\/wp\/v2\/expert-betting-guide"}],"about":[{"href":"https:\/\/www.scoresandstats.com\/es\/wp-json\/wp\/v2\/types\/expert-betting-guide"}],"author":[{"embeddable":true,"href":"https:\/\/www.scoresandstats.com\/es\/wp-json\/wp\/v2\/users\/34"}],"replies":[{"embeddable":true,"href":"https:\/\/www.scoresandstats.com\/es\/wp-json\/wp\/v2\/comments?post=96803"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.scoresandstats.com\/es\/wp-json\/wp\/v2\/media\/210418"}],"wp:attachment":[{"href":"https:\/\/www.scoresandstats.com\/es\/wp-json\/wp\/v2\/media?parent=96803"}],"wp:term":[{"taxonomy":"expert-betting-guide-category","embeddable":true,"href":"https:\/\/www.scoresandstats.com\/es\/wp-json\/wp\/v2\/expert-betting-guide-category?post=96803"},{"taxonomy":"expert-betting-guide-tag","embeddable":true,"href":"https:\/\/www.scoresandstats.com\/es\/wp-json\/wp\/v2\/expert-betting-guide-tag?post=96803"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Shop for the line on every bet<\/h2>\n\n\n\n
Bet only when the price is wrong in your favor<\/h2>\n\n\n\n
Size every bet as a unit of your bankroll<\/h2>\n\n\n\n
The Kelly criterion, if you trust your numbers<\/h2>\n\n\n\n
Parlays pay less than their odds suggest<\/h2>\n\n\n\n
Arbitrage and hedging lock in a result<\/h2>\n\n\n\n
Staking systems do not change the odds<\/h2>\n\n\n\n
Handicap and spread bets are a price in points<\/h2>\n\n\n\n