Free Betting Tools

Calculators for serious bettors

Five professional-grade calculators built for bettors who treat sports betting as a craft. No sign-up required, just open and use.

Arbitrage Calculator

Split a stake across both sides

When two sportsbooks price the same game differently enough that the implied probabilities total under 100%, a correctly split stake covers every outcome. This calculator finds the exact stake on each side, 2-way and 3-way markets, and shows the margin before execution risk.

American Decimal Fractional 2-way & 3-way Auto-stakes
Calculate arb stakes
Side A odds+150
Side B odds-120
Total stake$200
Stake A$77.42
Stake B$122.58
Guaranteed profit+$16.13
Parlay Calculator

Multi-leg payout calculator

Add 2 to 12 legs, mix any odds formats, and instantly see the combined odds, exact payout, and true win probability. Includes a warning when parlays become lottery tickets.

2-12 legs Mixed formats Win probability
Build a parlay
Odds Converter

Convert any odds format

Enter a number in any format (American, decimal, fractional, or implied probability) and see it instantly converted to all others. Includes a reference table of 15 common lines.

American Decimal Fractional Implied %
Convert odds
Hedge Calculator

Lock in profit or cut losses

Already have a bet running and want to hedge? Find the exact amount to bet on the other side to guarantee profit (or minimize loss). Supports free bet hedges and three strategic modes.

Equal profit Break even Free bet mode Custom
Calculate hedge
EV & Kelly Calculator

Bet sizing with an edge

Input your estimated win probability and the book's offered odds. The calculator shows expected value per $100 wagered, your edge percentage, and Full / Half / Quarter Kelly bet sizes with dollar amounts.

Expected value Kelly criterion Edge % Bankroll sizing
Find your edge

How sharp bettors use these tools

Professional sports bettors don't wing it, they quantify every decision. These calculators make that accessible.

01

Convert odds to understand true probability

Before evaluating any bet, convert the odds to implied probability. If you think a team has a 55% chance of winning but the odds imply 52%, you have a 3% edge.

02

Size bets proportionally with Kelly

The Kelly Criterion tells you what percentage of your bankroll to bet based on your edge. Betting too much relative to edge destroys bankrolls. Kelly keeps you in the game long-term.

03

Test two books for an arbitrage

When the combined implied probability from two books totals under 100%, the prices form a theoretical arbitrage. The calculator returns the exact stake split, but the math is only the first half; both bets still have to be accepted at those prices.

04

Size a hedge on an open ticket

If a parlay leg or futures bet is still live, an opposing bet reduces the exposure. The hedge calculator shows the stake for a given target, whether that leaves a gain depends entirely on the two prices involved.

Learn the concepts behind the tools

Calculators are only as powerful as your understanding of the underlying strategy.

Guide

How to Calculate Parlay Odds

The formula, the American-to-decimal conversions, and worked 2-leg and 3-leg examples.

Reference

Parlay Odds Chart: 2 to 12 Legs

Combined price, implied probability and payout for every leg count at −110 and at even money.

Guide

Can You Arbitrage Bet on One Sportsbook?

Why one book almost never prices both sides under 100%, and how arbitrage differs from a middle or a hedge.

Guide

How Often Do Arbitrage Opportunities Occur?

What controls the frequency, how long they last, and why no universal daily number is reliable.

Guide

NHL Puck Line Explained

What ±1.5 means, how overtime settles it, and how puck-line prices relate to the moneyline.

Guide

Sports Betting Arbitrage: Complete Guide

How arbs form, how to find them, which books to use, and how to manage your accounts for longevity.

Guide

What is Closing Line Value? The Pro's Performance Metric

Why CLV predicts long-term profitability better than your win/loss record, and how to track it.

Platform

How Nebula Insights Works

Line movement tracking, opening-to-closing history and multi-book odds comparison, plus what CLV and arbitrage actually mean.