Calculators
What a bet you type in is worth: what to stake on the other side, what a parlay of it pays, and what it converts to in cash. For markets you supply yourself, not ones the site found.
The screen, annotated
Every column, and what its number actually means.
The subtitle, and the boundary of the whole screen. Nothing here looks at live prices: you type the odds, the server does the arithmetic in Decimal and hands the number back. To have the site FIND prices instead, the page points you at the Hedge Finder under Edges and the Promo Optimizer and Boosts & Insurance under Promotions.
Takes a promo amount, the decimal price of the bet you put it on, the decimal price of the opposite side elsewhere, and any commission on that hedge. Returns the hedge stake that makes both outcomes pay the same, and what you are left holding either way.
Two modes that answer opposite questions. Bonus bet: how much cash a stake-not-returned free bet converts into. Qualifying bet: how much your own money it costs to unlock a promo. The first number is a profit, the second is a cost, and the screen colours them accordingly — green Guaranteed profit against orange Qualifying loss.
The guaranteed profit as a percentage of the promo's face value. A $100 bonus bet showing 70.97% is worth $70.97 in cash once hedged, which is the only figure worth comparing one promo against another with.
Multiplies the decimal price of every leg you enter (2 to 12) and shows the combined odds, the potential return on your stake, and an expected-value line. It prices legs you type. It does not search for them — the Parlay Builder under Edges, which shares the name, is the one that finds +EV combinations on the live board.
The product of each leg's implied chance, taken from the price you typed. A book's price carries its margin, so this is the chance the BOOK is charging you for, not the chance the parlay actually has. Nothing on this screen removes a margin from anything.
Type the same id on two legs and the result turns orange with "Correlated legs": multiplying probabilities is only valid for independent selections, and two legs from one game are not independent. Leave it blank on same-game legs and no warning appears, because the screen has no way to know.
Two or three decimal prices in, plus either a fixed total stake or a target profit, and it returns what to put on each side. This is the sizing arithmetic behind the Arbitrage board, unhooked from the board so you can run it on a pair of prices you found yourself.
One line per side: the price, the stake, and what that stake returns if that side wins. The returns match across sides by construction, which is what makes the profit guaranteed. Stakes are whole cents, so the guaranteed figure is the honest post-rounding minimum.
1/2.10 + 1/2.05 style arithmetic: under 1 is an arbitrage, at or over 1 is a normal market with the books' margin in it. The plan still renders below the warning so you can see the size of the loss, and the Guaranteed profit hero turns red.
The three controls that matter
Ignore everything else on a first read.
The three pills under the title
They are not filters, they are three separate calculators, and the one you want depends on what you already have. A promo you must spend: Bonus Bet Converter. Legs you want a combined price for: Parlay Builder. Two prices on opposite sides and a total to split: Arb Stake Sizing.
Hedge commission (0–1), and A / B commission
Prefilled from your saved exchange commission, which ships at 0.02. That is right when the hedge sits on an exchange charging a fee on net winnings, and wrong at every sportsbook — set it to 0 there. The server applies it as d_eff = 1 + (d - 1)(1 - c). So leaving it at 0.02 changes both the stake you are told to place and the profit you are told to expect.
Fixed total stake / Target profit
Which end of the arb sizer you pin. Fixed total stake answers "I have $1,000, split it". Target profit answers "I want $50 locked, what does that cost". The second is the honest way to learn that a thin edge needs more money than you have. Everything else on the screen can be left at its default on a first read.
A worked example
From a real row to a placed bet, including the stake.
Both branches land on the same number on purpose — that is what the hedge stake is solved for, and it is why the profit is guaranteed rather than likely. The 70.97% is the interesting part. The same $100 bonus bet placed at 2.00 and hedged at 2.00 converts at exactly 50%, because half of what a bonus bet pays is the stake you never get back. Longer odds on the promo leg convert better, which is why the advice is always to put a bonus bet on a price you would not otherwise take. Place the promo leg first and confirm it before you place the hedge: the hedge is ordinary cash and the whole plan depends on the promo having been accepted at the price you typed.
When it goes wrong
The price moved, a leg was voided, the row vanished. What to actually do.
"calculation failed" in red under the Calculate button, or "decimal odds must be > 1". You typed −110, or +150, or 110.
Every odds input on this screen is DECIMAL odds, and the server rejects anything at or below 1 rather than guessing. −110 is 1.91, +150 is 2.50, +200 is 3.00, and even money is 2.00. The display format you chose in Settings applies to results, not to what you type here — so a page showing you American odds everywhere still wants decimal in these boxes. If the number is above 1 and it still fails, check the commission fields: they take 0 to 0.99, so an exchange's 2% is 0.02 and not 2.
The arb sizer says "Not an arbitrage — the inverse sum is 1.0043, which is ≥ 1" and the guaranteed profit is red.
Believe it and do not place. The two prices together cost more than they can return; the plan shown below the warning is what that costs you on every outcome, not a plan to execute. Before giving up, check the two commission fields — a stale 0.02 on a sportsbook leg is enough to push a genuinely thin pair over the line. If the prices are right and the sum is still over 1, this is a normal market. The amount over 1 is the books' combined margin. Finding pairs where it goes under 1 is what the Arbitrage board does all day.
"Expected value" on the Parlay Builder reads 0.00%, and it keeps reading 0.00% whatever odds you enter.
That is the honest output, not a bug, and it is worth understanding rather than ignoring. The screen sends no fair probability, so the server falls back to each leg's own implied chance — 1 divided by the price you typed. Multiply those together and multiply the same prices together for the payout, and the two cancel exactly: EV is zero for every input, by algebra. Read it as "no opinion supplied". Get a real edge figure from the +EV board or the Parlay Builder under Edges — both measure a price against a fair price, rather than against itself.
Common mistakes
The specific ways people lose money with this tool.
Leaving the commission box at its prefilled 0.02 when the hedge is at an ordinary sportsbook.
Every number on the result panel is wrong in the same direction. On the example above, 0.02 turns a $129.03 hedge into $129.95 and a $70.97 conversion into $70.05. You overstake the hedge, your two outcomes stop matching, and you hand back $0.92 per $100 of bonus — $9.20 on a $1,000 promo, for nothing.
Set it to 0 unless the hedge really sits on an exchange that charges a fee on net winnings. Check the box every time rather than trusting the default — it loads from your saved preference, so it is sticky. When it does belong there, enter the rate as a fraction: 2% is 0.02.
Reading the Parlay Builder's "Expected value" as this parlay's edge, and taking 0.00% to mean the parlay is a fair bet.
You conclude a parlay breaks even when the number could not have said anything else — from this screen it is 0.00% for every input. The parlay you then place carries every leg's margin compounded: four legs at a 4.8% hold are roughly a 17% expected loss, sold to you by a row that read zero.
Use this tab for what it computes: the combined price, and the return on your stake. Get the edge from a tool that has a fair price to compare against — the +EV board, or the Parlay Builder under Edges, which only combines legs that are already +EV, one per event.
Expecting a fair price out of these calculators — typing a book's two prices in and treating what comes back as what the bet is worth.
Nothing on this screen removes a book's margin, so a number that looks like a probability is really the book's charge. A 4.8%-hold market read this way makes every bet look about 2.4% worse than it is on the side you want. Every conclusion from that comparison is off by the margin you forgot to subtract.
Get fair prices from the Odds Board and the +EV board, which de-vig for you. Know what they do: the default method is multiplicative — each side's implied chance divided by the sum of both, so both sides give up the same PROPORTION of the margin. Real books do not load margin evenly; they load more onto the longshot. So on a lopsided pair the multiplicative fair price is wrong in a predictable direction: too much probability left with the longshot, too little with the favourite. That flatters exactly the long prices a beginner is most tempted by. Power and Shin correct for that and are selectable on the grid when a market is lopsided enough to matter.