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.

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Arbitrage Calculator

Guaranteed-profit betting

When different sportsbooks price the same game differently, you can bet both sides for a guaranteed return. This calculator finds the exact stake on each side to lock in risk-free profit — supporting 2-way and 3-way markets.

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
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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
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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
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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
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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

Scan for arbitrage across books

When the combined implied probability from two books drops below 100%, an arbitrage exists. Use the arb calculator to find exact stakes and lock in profit with no risk.

04

Hedge winning tickets strategically

If a parlay leg or futures bet is close to winning, hedging guarantees you collect something. The hedge calculator shows exactly how much to bet on the other side.

Learn the concepts behind the tools

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

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, CLV measurement, arbitrage detection, and odds comparison — all in one platform.