Betting calculators that do the maths for you
13 free calculators for +EV, arbs, middles, dutching and every common promo: 2nd/3rd racing refunds, bonus bet conversion, boosts and multi savers. No account needed.
Promos & bonus bets
Work out what a promo is worth and how to turn a bonus bet into cash.
2nd / 3rd racing promos
Value a bonus-back-if-2nd/3rd, boost or pump from Betfair prices.
Bonus bet converter (exchange)
Lay stake and cash kept when you hedge a bonus bet on a horse at Betfair.
Bonus bet converter (cross-book)
Turn a bonus bet into cash by backing the other side at another bookie.
Odds boost
Is the boost +EV? And the lay that locks it in.
Money back if it loses
Value a refund-if-it-loses offer, paid as cash or a bonus bet.
Multi / SGM saver
Refund if one leg fails: what the saver adds to the multi.
+EV, arbs & middles
Find the edge, split the stakes and see every outcome before you bet.
+EV calculator
Strip the margin off a sharp market and see the edge in your price.
Arb calculator
Split one stake across bookies so every outcome pays the same.
Middles
Two lines, one window where both sides win.
Dutching
Back several runners in one race for the same return.
Lay / hedge
Hedge a bookie bet at the exchange, with commission.
Staking & odds
Size the bet and read the price any way it's written.
Betting involves risk. Bookmakers can restrict or close accounts and void bets, automation can fail, prices move, and a positive expected value (+EV) bet can still lose. Promotions carry each bookmaker's own terms. There is no guarantee of profit. See responsible gambling for limits and support.
By the B337 team. Last updated .