Best Odds Guaranteed (BOG): how it works on horse racing

Best Odds Guaranteed (BOG) is a bookmaker promotion on horse racing bets that pays the better of two prices: the odds you took or the Starting Price (SP) at the off. If the horse wins, a £10 bet at 5/1 that goes off at 7/1 returns £80 instead of £60.

BOG applies to bets placed before the off and only within one bookmaker; it is not a search for the best price across the market. The comparison concerns the price taken and the SP used to settle your eligible bet.

What is BOG for, and what does it not give you?

BOG protects an eligible early bet against missing out on a higher SP, while preserving the price taken if the odds shorten. It changes the return on a winning bet, not whether your selection wins.

With an ordinary fixed odds bet, a later price drift does not by itself increase your return. BOG adds a comparison at settlement: if the SP is higher, the promotion uses that higher price. If the SP is lower, the original price remains the basis for settlement, subject to the applicable rules.

That protection is narrower than the name might suggest. It does not turn a losing selection into a winner or automatically compensate for the bookmaker margin. Its value depends on the original odds, subsequent price movements and eligibility.

TNT Sports’ BOG guide, updated 30 June 2026, describes the comparison as the price taken versus the SP at the same bookmaker. Shopping around before placing a bet is therefore a separate task from using BOG.

How does BOG work with the Starting Price?

BOG compares the price taken with the official SP, which is a market price at the off derived from a sample of bookmakers for British horse racing—not simply the last price you happened to see on screen.

Under the SPRC rules for returning the SP (thesprc.org), the list of prices is divided into two halves. The SP is the shortest price in the half containing the longest prices. Here, “shortest” means lower odds and “longest” means higher odds. This is distinct from Betfair Starting Price or Tote settlement.

There are three practical scenarios:

• The price drifts. A higher SP increases the return on an eligible winning bet.
• The price shortens. The price taken is retained. There is no extra return compared with an ordinary fixed odds bet placed at that same price.
• A non-runner changes the settlement rules. The comparison may no longer work as in a straightforward race. The specific exception is covered below.

The distinction between the first two scenarios matters when assessing the promotion. A protected price is useful, but it is not necessarily an additional payment that a fixed odds bet would have missed.

How do you calculate a BOG payout?

For an eligible winning bet without deductions, multiply the stake by the higher of the two decimal prices. Returns include the stake; profit is the return minus the stake.

For the opening example, the calculation is:

• BOG return: £10 × 8.000 = £80.
• Profit after subtracting the stake: £70.
• Return at the price taken: £10 × 6.000 = £60.
• Additional return from BOG: +£20.

Use the odds converter to convert fractional prices such as 5/1 and 8/13 into decimal odds. The values here are 5/1 = 6.000 and 8/13 = 1.615. If the notation is unfamiliar, see how to read fractional odds.

Every row below assumes a winning £10 bet eligible for BOG, with no deductions or special exclusions. The decimal value for 8/13 is rounded, and its return is shown to the nearest penny.

Schematic: BOG payout for a £10 bet at 5/1 with SP 7/1Teaching diagram from our calculation: £10 at 5/1 returns £80 at SP 7/1 and £60 at SP 4/1 (BOG never pays below the taken price).

The final row separates two different comparisons. BOG preserves a £16.15 return, but the ordinary fixed odds bet would also return £16.15. The +£1.15 difference exists only against a bet struck at SP, returning £15. It is not an extra payment over the original fixed odds bet.

The same principle on another price pair: £100 at 4/5 that goes off at 11/10 returns £210 with BOG rather than £180 at the price taken (our calculation, not a quote from the Betfred terms). The corresponding decimal prices are 1.800 and 2.100. The principle is unchanged; the larger stake does not create a different kind of promotion.

Where and when does BOG apply?

BOG applies only when your account, timing and bet type meet the bookmaker’s terms. Check whether participation requires an opt-in before assuming that a bet qualifies; Sporting Life’s BOG guide says some bookmakers require one.

Betfred provides a specific timing example. Its Horse Racing Best Odds Guaranteed Promotion terms, on betfred.com, apply to bets placed after 08:00 on the day of the race. Terms as of 25 October 2026. This is one operator’s rule, not a universal BOG starting time.

Among the exclusions in those terms:

• Win bets and Each-Way bets on Super Extra Place Races.
• Lucky 15, Lucky 31 and Lucky 63.
• Ante post bets.
• Tote or Pari-Mutuel bets.
• bets paid with free bet funds, specials-market bets and boosts.

A Rule 4 deduction also changes the calculation: it is taken from winnings when a horse is withdrawn after the bet has been placed. It applies to the winnings portion, so multiplying the entire decimal price by a reduction factor is not the correct method. Betfred’s terms compare the relevant prices after the Rule 4 deduction and pay the bigger price. The simple payout table above does not model that adjustment.

For a non-runner, Betfred states that BOG does not apply if withdrawals cause the race to revert to SP-only settlement. That is an eligibility exception rather than an ordinary price movement.

A practical checking order is: confirm access to the promotion, check any opt-in requirement, check the qualifying time and bet type, then read the deduction and withdrawal rules. This keeps eligibility separate from the arithmetic.

Our calculation: when can BOG cover the margin?

Under these assumptions, BOG produces an expected +£0.07 per £10 bet (+0.7%) at a 5% margin, with q = 30% and d = 20%. The decisive assumption is q·d: reducing q from 30% to 15% flips the sign, producing −£0.215 per £10 (−2.15%).

This is a calculation of expected net profit, not the result of an individual bet or evidence of a profitable strategy. It compares the expected benefit of price improvements with an assumed margin.

The starting decimal price is 6.000, and the calculation assigns the win probability:

p = (1 − m) / 6.000

Here, m is the assumed margin. The implied probability calculator can help interpret the probability associated with odds, but a 5% margin assumption does not establish any particular horse’s true chance.

The remaining variables are:

• q: the share of cases where SP exceeds the price taken. For the payout benefit, the relevant frequency is among winners.
• d: the average relative increase in decimal odds when that drift occurs.
• EV: expected net profit per unit staked.

The calculation uses:

EV without BOG = −m

EV with BOG = −m + q·d·(1 − m)

Break-even: q·d ≥ m / (1 − m)

At a 5% margin, the break-even threshold is 5.26%. The base case has q·d = 6%, placing it above that threshold.

Without BOG, the base calculation gives −£0.50 per £10 (−5%). These are averages under the stated probabilities, not amounts that each bet will win or lose. The sensitivity results keep fractions of a penny because they are expected values, not individual settlements.

A meaningful personal calculation needs comparable records: the price taken, SP, result and whether BOG actually applied. A few memorable drifting winners are not enough. Nor can the drift frequency across all selections automatically stand in for its frequency among winners; the formula requires a suitable relationship between those observations.

Also keep d consistent: it is a relative increase in decimal odds, not the raw difference between two prices.

Under these assumptions, BOG covers the margin only when price rises are sufficiently frequent and large. If prices usually shorten before the off, it does not cover the margin. Sporting Life’s BOG guide says odds generally shorten as race time approaches, so the favourable base case should not be treated as typical without supporting observations.

What are the limits and common mistakes?

The main mistake is treating BOG as an unconditional bonus rather than a settlement promotion with specific eligibility rules. It should also be kept separate from other betting mechanisms.

Cash Out closes a bet before the finish, whereas BOG improves the price used for settlement. TNT Sports makes this distinction in its BOG guide.

A profit boost is a different promotion again. The profit boost calculator is for calculating an increase to the profit portion; BOG instead requires a comparison between the price taken and SP. Do not substitute one calculation for the other.

There are practical restrictions beyond the payout formula. Sporting Life reports that early bets may face limits, so the presence of BOG does not mean any desired stake will be accepted. Betfred’s terms also allow the bonus element to be voided in cases of collusion.

TNT Sports describes BOG as mainly a horse racing feature. Some bookmakers also offer it on greyhounds, and, according to TNT Sports’ October 2026 review, it does not apply to football.

Finally, terms can change. The dated operator example explains the mechanism; it does not confirm that the same offer is available to your account today.