Most online bookmakers have a bet calculator built into their bet slip, which means most punters never learn how the numbers actually work. That is a problem: if you cannot calculate a return by hand, you cannot spot when a bookmaker's calculator (or a badly explained system bet) is quietly short-changing you, and you cannot compare prices across bookies quickly. This guide explains the maths behind the most common UK horse racing bet types — each-way bets, Lucky 15s, Lucky 63s and accumulators — with fully worked examples using real numbers. Every calculation below can be checked with pen and paper.
View Today's Free AI PredictionsBritish bookmakers quote fractional odds such as 5/1. To work out a return you need the decimal equivalent: add 1 to the fraction. So 5/1 becomes 6.0, 3/1 becomes 4.0, and evens (1/1) becomes 2.0. A £1 win bet at 5/1 returns £1 × 6.0 = £6 — your £1 stake back plus £5 profit. Once every price in a bet is in decimal form, returns are simply stake × decimal odds, multiplied across every leg of a multiple. That single rule is the foundation of every calculation in this guide.
An each-way bet is two bets in one: a win bet and a place bet, at equal stakes. The place bet pays at a fraction of the win odds — usually 1/4 for most handicaps or 1/5 for non-handicaps and most big-field races. The place fraction varies by race type and field size, so always check the terms before you bet. See our full each-way betting guide for the complete breakdown of place terms.
A place-only bet uses the same maths but with no win part. A £2 place-only bet at 5/1 with 1/5 place odds pays: £2 × 5 × 0.2 = £2 profit, plus £2 stake back = £4 return. Your stake doubles when the horse places. The formula for any place bet is: stake × (win odds × place fraction) + stake.
An accumulator (acca) combines multiple selections into one bet; all must win. Returns are stake × decimal odds of every leg multiplied together. Because odds multiply rather than add, returns grow quickly — and so does the risk of a single loser wiping the bet out.
Decimal odds: 3.0, 4.0, 5.0, 6.0. Return = £2 × 3 × 4 × 5 × 6 = £720 from a £2 stake (£718 profit). Note how the £2 stake is multiplied through every leg — that is why the return is so much larger than the £2 × (3 + 4 + 5 + 6) = £36 you would get by adding the odds instead.
A Lucky 15 is a system bet covering 4 selections in 15 separate bets: 4 singles, 6 doubles, 4 trebles and 1 four-fold. Unlike an accumulator, it pays out even if only one selection wins — a single winner at 3/1 or bigger often recovers most of the stake. For the full rundown of the bet's structure, bonuses and quirks, see what is a Lucky 15?
At 2/1 every single returns £3, every double £9, every treble £27, and the four-fold £81:
With only one winner at 2/1 you get £3 back — a £12 loss, but far better than an accumulator, which would return £0. If your four selections carry different prices, calculate each line separately: a single pays stake × (odds + 1), a double pays stake × (odds₁ + 1) × (odds₂ + 1), and so on.
A Lucky 63 covers 6 selections in 63 bets: 6 singles, 15 doubles, 20 trebles, 15 four-folds, 6 five-folds and 1 six-fold. The combinations follow Pascal's triangle: for n selections there are C(n,2) doubles, C(n,3) trebles, and so on. With 10p per line the total stake is £6.30.
| Bet type | Selections | Number of bets | Total stake (£1/line) |
|---|---|---|---|
| Single | 1 | 1 | £1 |
| Double | 2 | 1 | £1 |
| Treble | 3 | 1 | £1 |
| Four-fold accumulator | 4 | 1 | £1 |
| Each-way single | 1 | 2 | £2 |
| Yankee | 4 | 11 | £11 |
| Lucky 15 | 4 | 15 | £15 |
| Canadian (Super Yankee) | 5 | 26 | £26 |
| Lucky 31 | 5 | 31 | £31 |
| Heinz | 6 | 57 | £57 |
| Lucky 63 | 6 | 63 | £63 |
HorsePicker's daily AI predictions cover every UK and Irish meeting, and they work with any of the bet types above. Many of our users build a Lucky 15 from the four highest-confidence selections, or place each-way singles on the strongest-rated runners at each meeting. There is no signup wall and no subscription — see today's free predictions or read our daily predictions guide to see how the confidence ratings map to staking. Whatever you build, run the maths above before you place the bet so you know exactly what each outcome returns.
Split the bet into a win part and a place part. For a £1 each-way bet at 5/1 with 1/5 place odds: the win part returns £1 × (5 + 1) = £6, and the place part returns £1 × (5 × 0.2 + 1) = £2. If the horse wins you get £8 back from a £2 total stake; if it only places you get £2 back (break even).
They are the place fraction: the place part of the bet pays a fraction of the win odds. At 1/5 odds, a 5/1 winner pays 5/1 × 1/5 = 1/1 (evens) for the place part. At 1/4 odds, an 8/1 winner pays 8/1 × 1/4 = 2/1 for the place part. Bookmakers use 1/4 for most handicaps and 1/5 for non-handicaps and most big-field races.
A Lucky 15 covers 4 selections in 15 bets: 4 singles, 6 doubles, 4 trebles and 1 four-fold accumulator. With a £1 per-line stake the total stake is £15. If all four selections win at 2/1, the full return is £255 — see the worked example in this guide.
A Lucky 63 covers 6 selections in 63 bets: 6 singles, 15 doubles, 20 trebles, 15 four-folds, 6 five-folds and 1 six-fold accumulator. With a 10p per-line stake the total stake is £6.30.
Convert every fractional price to decimal odds (a/b becomes 1 + a/b) and multiply them together, then multiply by your stake. A £2 four-fold of 2/1, 3/1, 4/1 and 5/1 returns £2 × 3 × 4 × 5 × 6 = £720.