Odds Calculator
Type any American price once and read all four languages at once — decimal, fractional, implied probability and payout — plus dedicated calculators for parlays, hedging and arbitrage — every one free, no sign-up, formula printed on the page.
Positive (+) = profit per $100 staked · Negative (−) = stake needed to profit $100. Everything computes live in your browser.
The four specialist calculators
Why a dedicated page for arithmetic
Because betting sites bury calculators behind logins, preload them with promotions, or price the "advanced" versions behind subscriptions. The math itself is public domain: three formulas cover the entire board, and every tool on this site runs them in plain sight — inputs, outputs and the formula on the page, checkable by hand. If a calculator will not show you its formula, that is not sophistication; it is a paywall with better manners.
The math each tool does, in one line each
Converter: decimal = 1 + odds/100 (positive) or 1 + 100/|odds| (negative); implied probability = 1 ÷ decimal. Parlay: multiply every leg's decimal price together — the product is the combined price. Hedge: stake on the other side = original stake × original decimal ÷ current decimal. Arbitrage: if the two sides' implied probabilities sum under 100%, a margin exists — split the stake proportionally to lock it. Every calculator shows its inputs, outputs and formula, so nothing is a black box; the learn page unpacks each idea in plain language.
Understanding what you are actually looking at, in one table
| You want to… | Start here |
|---|---|
| Read a price in plain probability | Implied probability — the concept behind every number |
| Bundle several bets into one ticket | Parlay calculator — the product rule, priced honestly |
| Protect a ticket that is one win from cashing | Hedge calculator — the exit math |
| Check whether two books disagree usefully | Arbitrage calculator — the margin test |
| Decode any board quickly | The conversion table — bookmark it |
Frequently asked questions
How do I convert American odds to decimal?
Positive odds: divide by 100 and add 1 (+150 → 2.50). Negative odds: divide 100 by the absolute value and add 1 (−200 → 1.50) — or type the price above.
What does +150 actually pay?
A $100 bet profits $150 and returns $250. The converter shows the profit for $100 at any price.
Is everything really free?
Yes. The calculators run in your browser — no account, no paywall, no "pro tier" hiding the formula.