Free tools
Free calculators for sports bettors
Work out a return, size a stake with Kelly, convert odds, measure the bookmaker’s margin, check your ROI or see how far luck swings results. Free, no sign-up, and nothing you type leaves your browser.
Bet calculator
Work out the return of any single, parlay or system bet (Trixie, Yankee, Lucky 15…), with losing and void legs, and the chance implied by the odds.
Open the toolVariance simulator
Simulate thousands of bettors with your odds and win rate to see how far luck alone swings results, how long losing runs last and what the margin does.
Open the toolKelly calculator
The stake the Kelly criterion suggests from the odds, your own win probability and your bankroll, in full, half and quarter Kelly. No edge, no stake.
Open the toolOdds converter
Convert betting odds between decimal, fractional and American formats and get the implied probability of any price, instantly and for free.
Open the toolMargin calculator
Enter the odds of every outcome of a market to get the bookmaker’s margin, the payout rate and the fair odds once the margin is taken out.
Open the toolROI calculator
Enter what you staked and what came back to get your net result, ROI and average stake, with a plain-language reading of what the numbers mean.
Open the toolLatest guides
Getting started
How to Track Your Sports Bets: The Complete Guide
Why tracking your bets changes how you see your results, what to record for each bet, and the easiest ways to do it: notebook, spreadsheet or app.
Tools
Bet Tracker App: How to Choose the Right One
What a bet tracker app should do, the criteria that matter (how bets get in, bookmakers, stats, privacy, export, price) and a checklist to compare apps.
Tools
Sports Betting Spreadsheet: Free Template and How to Use It
Download a free bet tracking spreadsheet for Excel or Google Sheets, with ROI and bankroll formulas and charts built in, and see when an app saves you time.
Your betting stats, finally clear.
Start tracking your bets today and see where you really stand.
