Free betting tools
Fast, free calculators — no signup required. Built on the same engine that powers Bankroll Guardian.
NFL teaser calculator
Enter your spreads to see the teased lines, whether each leg crosses the key numbers 3 and 7, and the win rate every leg needs to break even. A two-team six-pointer at −120 needs about 73.9% per leg — this shows why.
Open tool →Round robin calculator
Enter your picks to see how many parlays you're creating, your real total stake, and what you take home at every hit count — including the ones where winning half your picks still loses money.
Open tool →Parlay calculator
Enter each leg in American odds to get the combined price, payout and profit — plus a risk read: how often the parlay actually hits, the stacked vig you're paying, and which legs are the weak links.
Open tool →Odds converter & chart
Convert between American, decimal and fractional odds, see the implied win probability — plus a full betting odds chart of every common price.
Open tool →Bet calculator
Enter American odds and your stake to see the profit, total payout and implied win probability.
Open tool →Expected value (EV) calculator
Enter the odds and the win probability you believe to see whether a bet is positive expected value.
Open tool →No-vig & hold calculator
Enter both sides of a market to see the bookmaker’s hold and the fair, no-vig odds and probabilities.
Open tool →Closing Line Value (CLV) calculator
Compare the price you got to the closing line to see your CLV — the clearest sign of a long-term edge.
Open tool →Hedge calculator
Size a hedge bet on the opposite outcome so your profit is the same whichever way it lands.
Open tool →Arbitrage calculator
Enter both sides’ odds from different books to see if there’s an arb, and exactly how to split your stake for the same profit either way.
Open tool →Bankroll calculator
Enter your bankroll to get your unit size, compare 0.5%–10% staking plans side by side, and see how many consecutive losses each one survives before halving your bankroll.
Open tool →Kelly criterion calculator
Enter the odds, your estimated win probability and your bankroll to get the Kelly-optimal stake — full, half or quarter.
Open tool →Each way calculator
An each-way bet is two bets, so a £10 each way costs £20. Enter your price and place terms to see all three outcomes — and the price your selection needs before a place-only finish even breaks even.
Open tool →Dutching calculator
Back several outcomes for an identical return whichever wins. Shows the exact stake for each, and whether the prices you found sum to under 100% — because Dutching makes the result certain, not profitable.
Open tool →Break-even win rate calculator
Every price carries a win rate you must clear before making a penny — 52.38% at −110, not 50%. Shows the break-even rate, the ROI your win rate actually produces, and the rate needed for a target ROI.
Open tool →Middling calculator
A line move can leave you holding both sides at different numbers, with a band of results that wins both bets. Shows which results those are, what each band pays, and how often the middle must land — which turns out to be exactly the book's hold.
Open tool →Half point calculator
Books sell half points at a flat rate; football does not produce margins at a flat rate. Crossing 3 is worth about ten times crossing 9. Priced from a margin model fitted to 6,223 NFL games rather than a rule of thumb.
Open tool →Sample size calculator
Up over forty bets — good or lucky? Shows what your record actually establishes, and how many bets would settle it. Proving a 55% win rate at −110 takes about 2,200; a modest edge and a hot streak look identical for far longer than anyone expects.
Open tool →Trixie calculator
Three selections in 4 bets: 3 doubles and a treble. No singles, so you need at least two winners to see anything back. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Patent calculator
A Trixie plus the 3 singles — 7 bets. One winner returns something, which is what you are paying the extra 3 stakes for. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Yankee calculator
Four selections in 11 bets: 6 doubles, 4 trebles and a fourfold. Two winners is the minimum that pays. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Lucky 15 calculator
A Yankee plus the 4 singles — 15 bets. The most popular of the family, because a single winner still returns something. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Canadian calculator
Five selections in 26 bets: every double, treble, fourfold and the fivefold. Also sold as a Super Yankee. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Lucky 31 calculator
A Canadian plus the 5 singles — 31 bets. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Heinz calculator
Six selections in 57 bets — named for the 57 varieties. Every combination from doubles upward. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Lucky 63 calculator
A Heinz plus the 6 singles — 63 bets. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Super Heinz calculator
Seven selections in 120 bets. At this size the stake multiplies fast: £1 a line is £120. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Goliath calculator
Eight selections in 247 bets, the largest of the standard multiples. £1 a line is £247 before a single race is run. Enter your prices to see the real total stake and what comes back at every number of winners.
Open tool →Stop calculating by hand
Bankroll Guardian tracks every bet and shows your P&L, ROI, CLV and where you’re leaking — free to start.